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  • The influence of out-of-band modes in system inversion
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): K. Maes, G. Lombaert

    Model-based system inversion is a technique which allows reconstructing the forces applied to a structure and the corresponding system response using data obtained from a limited number of sensors and a dynamic model of the structure. Very often, modally reduced order models are used in system inversion, hereby reducing the number of modes to reduce the computational cost. This paper shows that the model order reduction can lead to large estimation errors in model-based system inversion. These errors are due to the disregarded quasi-static contribution of the out-of-band modes. Existing techniques for quasi-static correction cannot be straightforwardly adopted in the state-space models which are commonly applied in recursive system inversion. This paper therefore presents a novel computationally efficient approach where the quasi-static contribution of the disregarded modes is accounted for in the state-space model by means of dummy modes. The presented approach is validated using data obtained from a full-scale experiment on a footbridge. The results show that the proposed correction of the model significantly increases the estimation accuracy, as can be seen from the significant reduction in the error on the estimated forces.





  • 1 The Practice of Pediatric Anesthesia
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Charles J. Coté, Jerrold Lerman, Brian J. Anderson

    The basic principles of the practice of pediatric anesthesia can be applied regardless of the circumstances; they provide the foundation for safe anesthesia. Preoperative evaluation and management of both the child and caregivers is important. The benefits and risks of the anesthetic procedure must be presented in clear, easily understood terms. The child's medical record should be examined for pertinent information before induction of anesthesia. Anesthesiologists must fully understand the proposed surgical, medical or investigative procedure to facilitate the planning of an appropriate level of monitoring and selection of anesthetic drugs and technique. Ongoing communication between the anesthesiologist and surgeon is important if the anesthesiologist is to anticipate potential changes in a child's physiologic status due to surgical manipulations, and deal with them immediately, appropriately, and effectively. The most important aspect of basic monitoring consists of using the senses of sight, hearing, and touch to integrate all the data provided by patient observations and the monitors. The anesthesiologist's responsibility to a child does not end at completion of surgery but continues into PACU. Follow-up after anaesthesia determines patient level of satisfaction and identifies any complications that may have occurred.





  • 2 Growth and Development
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Bruno Marciniak

    Growth is the quantitative increase in physical development of the body, whereas maturation includes the genetic and biologic development of the child; both phenomena advance during pregnancy and continue after birth. All organ systems undergo maturation changes and most are complete within the first few years of life. Normal physiological variables in infancy and childhood are quite different from adults. Physical growth can be assessed by changes in weight, height and head circumference. These can be readily plotted over time to determine disparities between normalcy and those indicating disease onset or other effects compromising growth. Cerebral immaturity and plasticity impacts on sensitivity to drugs, pain responses, behaviour and increases potential harm from apoptosis with anesthesia. The heart undergoes transition from fetal to adult circulation during the first few weeks of life. Undiagnosed congenital defects are not uncommon. Respiratory anatomy and mechanics affect propensity to apnea, airway maintenance, artificial ventilation modalities, uptake of inhalational agents and endotracheal tube sizes. Metabolic rate and oxygen requirements decrease with age. This physiology influences diverse aspects that include the rate of desaturation during apnea, hypoglycaemia during starvation, cardiac output, drug metabolism, fluid requirements and heat production or loss. It is incumbent upon the anesthesiologist to understand the developmental changes that occur in the neonate and infant over time, and how these changes affect physiologic responses to diseases, drug pharmacokinetics and pharmacodynamics.





  • 4 Preoperative Evaluation, Premedication, and Induction of Anesthesia
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Elizabeth A. Ghazal, Marissa G. Vadi, Linda J. Mason, Charles J. Coté

    Adequate preparation of children for anesthesia allows optimization of medical conditions and leads to decreased morbidity. The medical history and laboratory testing obtained preoperatively aid the anesthesiologist in determining readiness for the planned surgery. Preparedness begins with adherence to a preoperative fasting schedule for elective surgery, selecting appropriate premedication, formulating an anesthetic plan and anticipating postoperative concerns. There are a variety of techniques for inducing general anesthesia. The technique used depends on a number of factors including the child's developmental age, understanding and ability to cooperate, previous experiences, the presence of a parent and the interaction of these factors with the child's underlying medical or surgical conditions. This chapter discusses special problems encountered in the pediatric population that require additional considerations from anesthesiologists. The preoperative period can be a stressful time for the fearful child and for those with autism spectrum disorders thus requiring the anesthesiologist to tailor the approach to meet the child's needs. Other challenges that pediatric patients present include respiratory system conditions such as obstructive sleep apnea syndrome, bronchopulmonary dysplasia, difficult airway, upper respiratory tract infections and apnea in former preterm infants. Additional conditions that are discussed include diabetes, seizure disorders, and sickle cell disease. Finally, the detection of a cardiac murmur, anemia or a fever before elective surgery will present a dilemma whether to proceed. The preoperative visit is an essential component of identifying the pediatric patient's needs and devising a plan that leads to a superior patient experience, a decrease in the number of cancellations and improved outcomes.





  • 5 Ethical Issues in Pediatric Anesthesiology
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): David B. Waisel

    Bioethics for pediatric patient centers on seeking, respecting and incorporating preferences from children of varying ages and maturity while incorporating the preferences of surrogate decisions makers, most often the parents. Operationalizing these practices requires understanding the following social, ethical, and legal concepts: (1) How age enables giving assent and consent; (2) The best interest standard in determining what care is acceptable for a child unable to communicate; and (3) Assent in determining the extent of authority given to children's preferences, particularly as they near the age of majority. These concepts help guide decision making about prickly issues for minors, such as confidentially, pregnancy, abortion, emergency care, end-of-life care, and when parents are too impaired to give informed consent.





  • 6 Pharmacogenomics
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Vidya Chidambaran, Senthilkumar Sadhasivam

    Pharmacogenomics is a rapidly evolving and novel science that has the potential to revolutionize the way we deliver anesthesia and analgesia to pediatric and adult patients. It allows for personalization of drug delivery tailored to an individual’s genetics and their consequent influence on drug metabolism, exposure and effects. In this chapter, we present some historical perspectives and basics of pharmacogenomics. Early discoveries in this field are tied to anesthesia, such as cholinesterase deficiency and malignant hyperthermia. We discuss developmental pharmacogenetics with relevance especially for the youngest pediatric patients, and then extensively describe the role of genetic variants of the phase I and II liver enzymes on the pharmacokinetics of commonly used drugs in anesthesia and analgesia. Particular attention is devoted to the CYP2D6 genetic variants which have recent implications in opioid analgesia, leading to regulations for codeine use in children less than 18 years old. Genetics affecting drug effects (pharmacodynamics) and perioperative outcomes like postoperative nausea are also described. The goal of understanding genomics is clinical translation to improve patient outcomes; costs and insurance coverage of genetic tests, limitations of research studies and interpretations of results and patient implications are deterrents to this goal. By integrating genomic data into electronic health records, creation of decision support systems and empowering anesthesia providers with information about pharmacogenomics, implications, and availability of current online sources, precision medicine is potentially poised to make anesthesia delivery safer and more efficient, although this is still a work in progress.





  • 7 Pharmacokinetics and Pharmacology of Drugs Used in Children
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Brian J. Anderson, Jerrold Lerman, Charles J. Coté

    The pharmacokinetics (PK) and pharmacodynamics (PD) of most medications in children especially neonates, differ from those in adults. Children exhibit different PK and PD from adults because of their immature renal and hepatic function, different body composition, altered protein binding, distinct disease spectrum, diverse behavior, and dissimilar receptor patterns. PK differences necessitate modification of the dose and the interval between doses to achieve the desired concentration associated with a clinical response and to avoid toxicity. In addition, some medications may displace bilirubin from its protein binding sites and possibly predispose to kernicterus in premature neonates. Drug effect may be influenced by altered capacity of the end organ, such as the heart or bronchial smooth muscle, to respond to medications in children compared with adults. In this chapter we discuss basic pharmacologic principles as they relate to drugs commonly used by anesthesiologists.





  • 8 Total Intravenous Anesthesia and Target-Controlled Infusion
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Brian J. Anderson, James Houghton

    Total intravenous anesthesia (TIVA) is the use of intravenous agents for induction and maintenance of anesthesia. The most frequently used agent is propofol. Propofol effect is usually augmented with an opioid (e.g., remifentanil). Although it is possible to implement TIVA using pumps with the infusion rate controlled manually, the advent of pumps programed with pharmacokinetic information has facilitated use. The use of published pharmacokinetic parameter sets (referred to as models and often described by the principle author) allows the pump to determine infusion rates to maintain a certain plasma concentration (Cp) or effect site concentration (Ce). Covariate knowledge (e.g., weight, age) allows individualization of dose. There are limited data in the neonatal and infant populations. Common indications for TIVA techniques include children at risk for malignant hyperthermia, procedures with a high risk of postoperative nausea and vomiting, brief radiologic or painful procedures when rapid recovery is needed and frequent repeated anesthesia. However, use is spreading to other fields. Fears that children may develop propofol infusion syndrome during routine anesthesia have not eventuated.





  • 9 Fluid Management
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Craig D. McClain, Michael L. McManus

    Fluid and electrolyte disturbances are common among children and fluid management is critical to the successful care of a wide range of pediatric conditions. This chapter outlines the basic anatomy and physiology of fluid compartments, their developmental maturation, and a general approach to fluid administration. Clinical assessment of hydration states, perioperative fluid management, and the care of common pathophysiologic states are discussed in detail. Specific attention is given to acid–base balance and to disorders of sodium, potassium, and water homeostasis.





  • 10 Essentials of Hematology
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Trevor L. Adams, Gregory J. Latham, Michael J. Eisses, M.A. Bender, Charles M. Haberkern

    Pediatric hematologic diseases, while relatively uncommon, pose significant morbidity and mortality. These children commonly undergo a host of diagnostic or therapeutic surgeries and procedures that require anesthesia. A sound understanding of hematological physiology across all age groups is required to safely anesthetize these children. In addition, the complexity of treatment options for many hematologic disorders have expanded, including hematopoietic stem cell transplant, which highlights the need to collaborate perioperatively with the child's hematologist, surgeon, or oncologist for optimal care.





  • 12 Strategies for Blood Product Management, Reducing Transfusions, and Massive Blood Transfusion
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Charles J. Coté, Eric F. Grabowski, Christopher P. Stowell

    This chapter presents a review of all blood components, the storage and processing of blood products, specific indications for administration of platelets, fresh frozen plasma, cryoprecipitate, factor concentrates, albumin, dextrans, starches, and gels. Basic estimations are detailed of the circulating blood volume, formulas for correcting anemia, thrombocytopenia, or other factor deficiencies are detailed. Indications are presented for leukocyte-reduction, risk for cytomegalovirus transmission, children at risk for transfusion-associated graft-versus-host disease, as well as the indications for and risks associated with blood product irradiation. The chapter offers considerable detail regarding massive blood transfusion from the perspective of the pediatric patient, particularly infants, with a comprehensive discussion of potential complications such as dilutional thrombocytopenia, dilutional coagulopathy, factor deficiency, acute hypocalcemia (citrate toxicity), hyperkalemia, changes in acid-base balance, and the potential adverse effects of hypothermia. Associated issues are also discussed such as transfusion associated circulatory overload (TACO) and transfusion-related acute lung injury (TRALI). The chapter describes the risks for infectious disease transmission and the remarkable overall safety of blood transfusion in the age of modern blood banking. New threats from endemic infections such as Dengue, Chikungunya, malaria, the Zika virus and the technical and logistical limitations for screening for such rare pathogens are considered. Additionally, a comprehensive discussion is presented of methods to reduce patient exposure to allogenic blood components, such as presurgical administration of erythropoietin, preoperative blood donation programs, intraoperative blood recovery, autotransfusion, controlled hypotension techniques, and normovolemic hemodilution and the associated risks.





  • 13 Essentials of Pulmonology
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Paul G. Firth, T. Bernard Kinane

    Pulmonary complications are a major cause of perioperative morbidity in the pediatric population. Although preexisting pulmonary pathologic processes in children can present significant challenges to anesthetic delivery, a thorough assessment of the problem combined with meticulous anesthetic management allows most children to undergo surgical interventions without long-term adverse sequelae. Asthma, cystic fibrosis and sickle cell disease continue to pose challenges during anesthesiology. Consultation with a pediatric pulmonologist is indicated when appropriate for specific problems as outlined in this chapter; a team approach may markedly improve operative and postoperative outcomes.





  • 14 The Pediatric Airway
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): John E. Fiadjoe, Ronald S. Litman, Julia F. Serber, Paul A. Stricker, Charles J. Coté

    This chapter reviews the developmental anatomy and physiology of the pediatric upper airway as it relates to the practice of pediatric anesthesia. Differences between the pediatric and adult airways are important determinants of anesthetic techniques. Knowledge of normal developmental anatomy and physiologic function is required to understand and manage both the normal and the pathologic airways of infants and children. Techniques of mask ventilation, oral and nasal airway placement, use of supraglottic devices, and tracheal intubation are reviewed for normal and anatomically abnormal pediatric patients.





  • 15 Anesthesia for Thoracic Surgery
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Gregory B. Hammer

    Anesthesiologists caring for infants and children who require a thoracic surgical procedure face many challenges. In particular, the airway equipment needed requires special skills and understanding of the limited space available in the airway for proper placement of special tracheal tubes. A working knowledge of respiratory physiology and anatomy in infants and children is also required for the planning and execution of appropriate intraoperative care. The appropriate airway device and its size in a particular child depend on the pathology being managed, physiological changes, the child's age and size and the surgical technique used. Specialized techniques such as anesthesia for thoracoscopy or video assisted thoracic surgery (VATS), one lung ventilation and anesthesia related issues, the use of bronchial blockers, Univent tubes, double lumen tubes, and consideration of specific lesions such as subglottic stenosis, pulmonary sequestration lesions, bronchogenic cysts, cystic adenomatoid malformation, congenital lobar emphysema, congenital diaphragmatic hernia, tracheoesophageal fistula and esophageal atresia are discussed. The pathophysiology and management strategies for anterior mediastinal masses, including an algorithm for evaluation of these masses, are also presented.





  • 16 Essentials of Cardiology
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Wanda C. Miller-Hance, Ralph Gertler

    Congenital heart disease (CHD) is the most common birth defect affecting approximately 1% of live births. Although CHD is the leading cause of neonatal mortality, advances over the last several decades including significant contributions related to anesthesia care, now allow for survival of most affected infants. The wide spectrum of congenital cardiovascular anomalies and the various types of acquired heart disease in the pediatric age group presents a challenge to the clinician who does not specialize in the care of these children. Even for those with a focus or interest in cardiovascular disease, the range of structural defects, myocardial disorders, and other conditions, and the varied associated hemodynamic perturbations can be overwhelming. The ability to provide optimal perioperative care to affected children heavily relies on a clear understanding of the basic pathophysiology of the congenital anomalies and acquired diseases, familiarity with the commonly used diagnostic modalities in cardiology and their clinical applications, and medical and surgical treatment options available to affected individuals. In this chapter, we present essential concepts in cardiology to enhance the overall knowledge of the practicing anesthesiologist in pediatric cardiovascular disease.





  • 17 Anesthesia for Children Undergoing Heart Surgery
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Angus McEwan, Vasco Laginha Rolo

    This chapter outlines anesthesia for cardiac surgery in children. These children require a thorough preoperative evaluation and an assessment of a number of perioperative challenges including cyanosis, intracardiac shunting and impaired hemostasis. The anesthetic management during cardiopulmonary bypass focuses on monitoring, induction and maintenance of anesthesia and the institution of and separation from bypass. Depending on which heart defect is present, the variables and drugs that control both systemic and pulmonary vascular resistances during anesthesia are detailed. In addition, a review of the drugs used in pediatric cardiac anesthesia, the use of regional anesthesia in these children, fast-tracking, cardiopulmonary bypass and the stress response to cardiac surgery are discussed. The anesthetic considerations for specific cardiac defects including left-to-right shunts, right-to-left shunts and aortic stenosis are presented. Finally, the considerations for transport and transfer of these children after surgery to the pediatric intensive care unit are outlined.





  • 18 Cardiac Physiology and Pharmacology
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Annette Y. Schure, James A. DiNardo

    This chapter describes important features of the fetal circulation, essential changes at birth and other age-specific developments of the cardiovascular system. The incidence, prevalence and basic pathophysiological principles of congenital heart defects are presented. Several special situations are discussed in more detail: the exercise physiology of patients with repaired congenital heart disease, the Fontan physiology and the transplanted heart. Indications and practical considerations for the use of various vasoactive and antiarrhythmic drugs are reviewed.





  • 19 Cardiopulmonary Bypass and Management
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Ralph Gertler, Erin A. Gottlieb, Dean B. Andropoulos

    Cardiopulmonary bypass (CPB) is an imminent element of today's cardiac surgery. Major differences not only exist in setup and materials, but also in management strategies. The phases of CPB are similar to the adult, but the effects on the body and the physiological disturbances are far more pertinent. Hemodilution is the major hematologic disturbance that leads to coagulation deficiencies and challenges the oxygen transport capacities of the body. Hemodilution and the membrane oxygenator itself change the pharmacokinetics and pharmacodynamics of most anesthetics in use. Physiological limits are permanently reached during pediatric cardiac surgery and are most obvious during the care of Jehova's Witness patients. Lower body temperatures than in adults are routinely used which influences acid base management. Special techniques applied are deep hypothermic circulatory arrest and selective cerebral perfusion which enable a broad spectrum of today's congenital cardiac surgery. Despite technical advances widespread effects on the body systems remain and these changes can prolong the postoperative course and endanger a primarily successful repair.





  • 23 Anesthesia for Noncardiac Surgery in Children With Congenital Heart Disease
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Wanda C. Miller-Hance

    The last several decades have seen remarkable advances in medical and surgical care of children with congenital heart disease (CHD). This progress has resulted in decreased morbidity and overall improvements in long-term clinical outcomes. As survival rates continue to improve, an escalating number of affected children will present for noncardiac surgery or other procedures unrelated to their heart disease. The care of these children is becoming more common in all diagnostic and surgical venues. The challenges of caring for children with CHD for noncardiac surgery are magnified by the wide range of defects, each with specific physiologic perturbations, hemodynamic consequences, and severity of disease. This is further complicated by the variety of medical and surgical strategies available for management of these conditions. Optimal anesthesia care requires a thorough understanding of the underlying cardiovascular anatomic abnormalities, pathophysiologic consequences of the malformation, functional status, residua, sequelae, and expected long-term outcome, in addition to the planned procedure and potential complications. In this chapter, general principles of anesthesia practice are reviewed, as they pertain to the care of children with CHD during noncardiac surgery. Unique perioperative considerations and issues applicable to high-risk patient groups are also addressed.





  • 24 Essentials of Neurology and Neuromuscular Disorders
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Peter M. Crean, Sandya Tirupathi

    Despite the increasing safety of anesthesia, perioperative cardiopulmonary resuscitation in infants and children remains a common event. Successful resuscitation to spontaneous circulation requires early recognition and coordination of a team of practitioners to function effectively to deliver best practice CPR. Additionally, the perioperative and operative environment adds further challenges to delivery of effective CPR. Vigilance and following best evidence practice remain critical for the prevention and mitigation of critical events in the perioperative setting.





  • 25 Surgery, Anesthesia, and the Immature Brain
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Andreas W. Loepke, Andrew J. Davidson

    Millions of children are exposed to general anesthetics every year to undergo surgical operations and painful interventions worldwide. Research in animals has raised substantial concerns regarding the effects of anesthetic exposure on the developing brain and several epidemiological studies have addressed this important clinical concern. This chapter assesses available animal studies into the effects of commonly used anesthetics on brain structure and cognitive function and their relevance to clinical pediatric anesthesia practice as well as the current clinical evidence. Studies were identified using searches of medical databases, queries of recent review articles, and personal records. The number of laboratory studies into anesthetic neurotoxicity has increased dramatically in the past 10 years, demonstrating compelling evidence for both brain structural abnormalities as well as impaired long-term cognitive outcomes following prolonged exposure to anesthetics early in life. In humans, several epidemiological studies have associated anesthesia for surgery early in life with subsequent neurobehavioral abnormalities, while others, including the interim results of a randomized controlled trial as well as a recent ambi-directional study, have not found any effect of inhaled anesthetic exposure in infancy on subsequent cognition. However, the potentially most susceptible age as well as the phenomenon's underlying mechanisms are not well described. Accordingly, given the serious implications for public health, further research, both in animals and in humans, is urgently needed to better define human applicability of animal data and to devise potential mitigating strategies.





  • 26 Pediatric Neurosurgical Anesthesia
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Craig D. McClain, Sulpicio G. Soriano

    Children who require neurosurgical procedures present unique challenges to pediatric anesthesiologists. In addition to common concerns of anesthetizing children, anesthesiologists must pay special attention to the effects of anesthesia on the developing central nervous system of children. An understanding of normal neurodevelopment throughout childhood is essential to effectively care for children with neurologic and neurosurgical disease. Further, a thorough understanding of the pathophysiology of a variety of central nervous systems processes is incumbent upon the anesthesiologist caring for children with such diseases. Practitioners must account for both normal and abnormal variants of intracranial pressure, cerebral blood flow, cerebral perfusion pressure and cerebrovascular autoregulation. Special attention must be paid to basic aspects of pediatric anesthetic practice when caring for children with central nervous system pathology. Such aspects include preoperative evaluation, premedication, monitoring, airway management, positioning, fluid management, and emergence. Patients undergoing a variety of neurosurgical procedures may be at particular risk for venous air emboli and caregivers must understand the pathophysiology, monitoring, and treatment of this potentially catastrophic event. Finally, anesthesiologists must have a strong grasp of the anesthetic implications as they relate to a wide variety of neurosurgical procedures performed on children. These include craniotomy, brain biopsy, revascularization procedures, shunt surgery, endoscopic procedures, and care of neurotrauma. Many of these procedures may need to be performed in potentially hostile, off site locations such as the diagnostic radiology, interventional radiology or intraoperative MRI suite.





  • 27 Essentials of Endocrinology
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Elliot J. Krane, Erinn T. Rhodes, Rebecca E. Claure, Echo Rowe, Joseph I. Wolfsdorf

    This chapter presents the most up to date recommendations regarding the perioperative management of children with diabetes. All the commonly used insulin preparations are discussed along with their pharmacokinetic and pharmacodynamic profiles. The chapter is loaded with detailed decision algorithms for all expected surgical/anesthesia related issues such as intraoperative insulin infusions. In particular methods for accurately estimating the need for additional insulin and what type of insulin is recommended as it relates to current hyperglycemic values and the child’s normal daily insulin requirements (“correction factor” calculation). Diabetes insipidus, the syndrome of inappropriate antidiuretic hormone secretion, thyroid disorders, thyroid crisis, hypercalcemia, hypocalcemia, adrenal insufficiency, steroid replacement therapy, and management strategies for pheochromocytoma are also presented. All aspects are presented from the perspective of pediatric specialists and pediatric anesthesiologists to achieve the most cogent recommendations.





  • 28 Essentials of Nephrology
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Delbert R. Wigfall, John W. Foreman, Warwick A. Ames

    The basic functions of the kidney are to maintain fluid and electrolyte homeostasis and metabolism. Renal disease requires the practitioner to be vigilant about fluid homeostasis, acid-base balance, electrolyte management, choice of anesthetics, and potential complications. This requires a thorough understanding of the excretory and fluid homeostatic functions of the kidney, particularly in the neonate and younger child. If not managed assiduously, perioperative renal dysfunction can deteriorate into renal failure or multiorgan system failure resulting in significant morbidity or mortality. The anesthesia provider must understand renal physiology, appropriate preoperative preparation, intraoperative management, and postoperative care of the child with renal disease.





  • 29 General Abdominal and Urologic Surgery
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Tom G. Hansen, Steen W. Henneberg, Jerrold Lerman







  • 31 Organ Transplantation
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Franklyn P. Cladis, Brian Blasiole, Martin B. Anixter, James Gordon Cain, Peter J. Davis

    End organ failure in children frequently ends in the need for organ transplantation. Improvements in surgical techniques coupled with advancements in the understanding of immunosuppression have increased patient survival and patient quality of life. This chapter deals with the anesthetic management of these challenging patients as well as describing morbidity and mortality statistics associated with these surgical procedures and underlying disease states.





  • 32 Orthopedic and Spine Surgery
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Niall C. Wilton, Brian J. Anderson

    Anesthesia for orthopedic and spine surgery provides a multitude of challenges. Children often present with concomitant diseases that affect cardiovascular and respiratory function. Operating times can be protracted, particularly for scoliosis surgery. Many of these procedures involve children already severely compromised by muscle weakness and impaired respiratory function. Improvement in monitoring of spinal cord function help minimize neurological risk. Significant blood loss can occur that requires strategies for blood product management and transfusion reduction. Major trauma causing orthopedic injuries invariably involves other organ systems that may adversely interact with or compromise anesthesia management. The risks of pulmonary aspiration of gastric contents and the requisite fasting times, after even minor trauma involving an isolated forearm fracture, continue to be debated. Fat embolus is uncommon in children with long-bone fractures but should be considered in any child with hypoxia and altered consciousness in the perioperative period. Tumor surgery may be complicated by chemotherapy, altered drug disposition, or bone grafting considerations akin to those for plastic and reconstructive surgery and complex postoperative pain management may be required. Positioning children on the operating table involves care, especially for those with limb deformities and contractures. Patients with a variety of syndromes also require other orthopedic procedures to assist in minimizing the impact of those syndromes on their quality of life. These syndromes present their own unique anesthetic challenges. The anesthesiologist's role facilitating surgery and providing optimal postoperative care, particularly pain management, should not be underestimated.





  • 33 Otorhinolaryngologic Procedures
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Raafat S. Hannallah, Karen A. Brown, Susan T. Verghese

    Providing safe anesthesia for pediatric otolaryngological procedures requires complete understanding of the pathophysiology of the diseases being treated. Not only does the surgeon share the airway with the anesthesiologist, but the ability of the surgeon to safely and successfully complete the planned procedure depends on an airway that is well anesthetized (e.g., without coughing, laryngeal spasm or other reflex responses) and secure. Although it is the primary responsibility of the anesthesiologist to monitor the child's vital signs, the surgeon needs to understand that in many situations the procedure may have to be interrupted to verify that ventilation and oxygenation are not compromised. Drugs administered during surgery, such as anti-emetics and opioids, may profoundly impact the course of the perioperative period. This chapter reviews all the common anesthetic related issues for children undergoing otolaryngological procedures with particular emphasis on children with obstructive sleep apnea, management of subglottic stenosis, diagnostic laryngoscopy and bronchoscopy, epiglottitis, laryngeal papillomatosis, tracheostomy, laryngeal reconstruction and others.





  • 34 Ophthalmology
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Joseph R. Tobin, R. Grey Weaver

    Anesthesia assessment, induction, maintenance and recovery may be complex for ophthalmology procedures. Not only is the ophthalmologic procedure a major consideration, but the concurrent medical conditions associated with the ophthalmologic disorder may hold implications for airway management and cardiorespiratory challenges. Premature infants often need anesthesia for all ophthalmologic procedures and complications of prematurity may manifest themselves. Careful planning and communication with the ophthalmologist increases the likelihood for an uncomplicated anesthetic and postoperative recovery period. We review the physiology and specific conditions that require careful consideration when planning anesthesia for these children.





  • 35 Plastic and Reconstructive Surgery
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Paul A. Stricker, John E. Fiadjoe, Jerrold Lerman

    A wide variety of plastic surgical procedures are performed in infants and children of all ages. Children presenting for plastic surgery present with a specific set of management challenges that are determined by the surgical procedure performed (e.g., blood loss management in craniosynostosis surgery) and the associated comorbidities (e.g., difficult airway management for mandibular distraction surgery). An optimal and nuanced approach to management is facilitated by an understanding of both the procedures performed and underlying diseases. Presented in this chapter are a selection of key plastic/reconstructive procedures, associated diagnoses and their relevance to care, and management pearls.





  • 36 Burn Injuries
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Erik S. Shank, Charles J. Coté, J.A. Jeevendra Martyn

    Pediatric burn injuries present unique challenges to the anesthesiologist. These include alterations in physiology and pharmacology, as well as technical challenges with airway management, vascular access, pain management, and physiological monitoring. This chapter uses a systems approach to discuss the unique pathophysiology of the burn patient, the pharmacological alterations, and addresses some special circumstances including the management of inhalational injuries, electrical burns, carbon monoxide poisoning, and cyanide poisoning. Post-operative pain management, opioid sparing techniques, and regional anesthesia for the burn patient are also discussed.





  • 37 The Extremely Premature Infant (Micropremie) and Common Neonatal Emergencies
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): James P. Spaeth, Jennifer E. Lam

    The preterm infant, defined as birth before 37 weeks gestation, provides unique medical and surgical challenges to health care providers due to a myriad of anatomical underdevelopments and physiologic derangements. The physiology of prematurity as it relates to anesthesia is of particular importance when preparing for surgery. Anatomic differences of the premature airway and altered respiratory mechanics, such as a smaller airway diameter, increased oxygen consumption, bronchopulmonary dysplasia and apnea place these infants at risk for rapid and profound desaturation and hypoventilation during anesthesia. The immature heart has not had time to develop sufficient muscle fibers for optimal contractility. In addition, persistent pulmonary hypertension of the newborn may develop when right-to-left shunting of blood occurs through a patent ductus arteriosus and/or a patent foramen ovale due to failure of the pulmonary vascular resistance to drop at birth. These factors may combine and lead to significant cardiovascular collapse during surgery. Premature infants are susceptible to metabolic derangements such as hypoglycemia and hypocalcemia due to improper storage and loss of maternal-fetal transfer during gestation. The liver and kidneys are underdeveloped, leading to altered drug metabolism, thus, anesthetic drugs must be tailored accordingly. Neonatal surgical emergencies, such as congenital diaphragmatic hernia, hypertrophic pyloric stenosis, necrotizing enterocolitis and gastroschisis, can present at any time and be life-threatening. Immediate surgical intervention is not always necessary and there is often time for medical optimization. Advances in neonatal care have improved the morbidity and mortality of critically ill newborns.





  • 38 Fetal Intervention and the EXIT Procedure
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Roland Brusseau

    Fetal intervention allows surgical correction or amelioration of known congenital defects in utero. With improvements in prenatal imaging and surgical techniques, fetal interventions have grown to include diagnoses associated with intrauterine demise, as well as diseases associated with significant postnatal morbidity. The goal of fetal intervention is to improve the chances of normal fetal development and minimize postnatal morbidity. Increasingly, advances have changed some procedures from open in-utero interventions, which are associated with significant maternal risk, to percutaneous or fetoscopic techniques, thus improving the maternal risk-to-benefit ratio while diminishing postoperative uterine contractions associated with open procedures. Fetal surgery often requires the anesthesiologist to care for two or more patients at once, all with distinctive and, at times, conflicting requirements. The first is the mother who can express her level of discomfort, who can be monitored directly, and to whom drugs can be administered easily. The second (and possibly third) is the fetus. For the latter, detecting pain depends solely on indirect evidence, monitoring is limited at best, administering drugs is more complicated, and there is the possibility of long-term effects from procedures and drugs administered during early development. The anesthesiologist is required to provide both maternal and fetal anesthesia and analgesia while ensuring both maternal and fetal hemodynamic stability; a plan must be prepared to resuscitate the fetus if problems occur during the intervention.





  • 39 Trauma
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): David A. Young, David E. Wesson

    Traumatic injuries are the most common cause of death within the United States for children more than one year of age. Pediatric patients with traumatic injuries can vary in complexity ranging from an isolated foot fracture to a life-threaten traumatic brain injury requiring emergent surgery. Strategies of Advanced Trauma Life Support (ATLS) should be utilized in the perioperative setting to effectively care for pediatric trauma patients. These strategies include recognition of cardiopulmonary disorders, volume resuscitation, and prevention of additional injuries including to the cervical spine. Trauma patients may present hemodynamically unstable and with unclear circumstances. Patient information may be limited including important details such as past medical history, past surgical history, and drug allergies. Although the general principles of resuscitation for pediatric trauma patients are similar to those used for adults, effective management of the pediatric trauma patient also requires an appreciation of the anatomical, physiological, developmental, and emotional characteristics that differentiate children from adults. The management of pediatric trauma patients typically includes the involvement of a multidisciplinary team. Anesthesiologists comprise an important role within this team in many capacities. To deliver effective care to the pediatric trauma patient, anesthesiologists must become proficient with the initial evaluation and resuscitation of the pediatric trauma patient and continue this process throughout the perioperative period. Anesthesiologists, surgeons, and other personnel should work together as a synchronized team when managing children with traumatic injuries.





  • 40 Cardiopulmonary Resuscitation
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Sandeep Gangadharan, Pooja Nawathe, Charles L. Schleien

    Despite the increasing safety of anesthesia, perioperative cardiopulmonary resuscitation in infants and children remains a relatively common event. Successful resuscitation to spontaneous circulation requires early recognition and coordination of a team of practitioners to function effectively to deliver best practice CPR. Additionally, the perioperative and operative environment adds further challenges to delivery of effective CPR. Vigilance and following best evidence practice remain critical in the prevention and mitigation of critical events in the perioperative setting.





  • 41 Malignant Hyperthermia
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Jerrold Lerman, Jerome Parness

    Malignant hyperthermia (MH) is a pharmacogenetic disease that is the sole life-threatening disease triggered by inhaled anesthetics and succinylcholine. Identification of the signs and symptoms of an acute MH reaction (the first sign is an increased end-tidal carbon dioxide partial pressure) has been instrumental in establishing diagnostic tests and treatments. The caffeine-halothane contracture test remains the gold-standard test to diagnose MH against which the more recent genetic testing is compared. The primary mutation associated with MH to date is the ryanodine receptor defect on chromosome 19, which is an important gatekeeper for calcium release from the sarcoplasmic reticulum. Several other genetic mutations have also been associated with MH. The diminution in mortality from MH over the past several decades has been attributed to appreciating the signs of an acute MH reaction and the availability of dantrolene. The pharmacokinetics of dantrolene have been delineated in children to guide treatment. MH has been associated with several muscle disorders (e.g., central core myopathy) and shares characteristics with others (e.g., heat stroke). Monitoring of those who develop MH reactions should continue until all signs of MH have abated. Preparation of AWSs for MHS patients includes replacing the carbon dioxide absorbent, airway breathing circuit and flushing the AWS while the ventilator is active for at least 10 minutes and most recently, insertion of charcoal filters in the breathing circuit. All patients who develop MH reactions should be counseled regarding muscle biopsy testing (if adults) and referred for a MedicAlert bracelet.





  • 42 Regional Anesthesia
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Santhanam Suresh, David M. Polaner, Charles J. Coté

    Regional anesthesia has become an integral and common component of both intraoperative anesthesia and postoperative analgesia in infants and children. Advantages of regional blockade include the reduction of general anesthetic dose requirements, effective blunting of hemodynamic and autonomic responses, and excellent postoperative analgesia with decreased requirement of systemic analgesics and their concomitant side effects. For many orthopedic operations, increasing use of peripheral nerve blockade permits the anesthesiologist to provide long durations of analgesia limited to the surgical site. Spinal anesthesia in infants has been demonstrated to be an effective alternative to general anesthesia for subumbilical operations lasting an hour or less. However, the risks of local anesthetic toxicity may be magnified in infants and children because of their size and immaturity, and great care and precision must be used when choosing volume and concentration. Because the vast majority of regional blocks in children are performed with patients under general anesthesia, early signs of toxicity are usually obscured. The emergence of lipid emulsion therapy for local anesthetic systemic toxicity has dramatically altered our approach and the successful outcome to these events and should be administered promptly. Large-scale prospective data from multicenter collaborative studies have documented that regional anesthetics in children have a high degree of safety, and prospective data have confirmed that administering blocks to children under general anesthesia confers no increased risk of injury. While one must have specific technical skills, as well as an understanding of the differences in pediatric physiology, anatomy, and pharmacology, to use regional blockade in infants and children, the benefits of these techniques are great.





  • 43 Ultrasound-Guided Regional Anesthesia
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Manoj K. Karmakar, Wing H. Kwok

    Peripheral nerve blocks are frequently performed in children to provide anesthesia or analgesia during the perioperative period. Success depends on the ability to accurately place the needle—and thereby the local anesthetic—close to the target nerve without causing injury to the nerve or adjacent structures. In the past, clinicians relied on anatomic landmarks, fascial clicks, loss of resistance, or nerve stimulation to position the needle in the vicinity of the nerve. Anatomic landmarks provide valuable clues to the position of the nerve, but they are surrogate markers, lack precision, vary among children of different ages, and may be difficult to locate in obese children. Even nerve stimulation, which has been recommended as the gold standard for nerve localization, may not always elicit a motor response and its use does not guarantee success or preclude complications. Moreover, the accuracy of needle placement cannot be predicted with any of these methods, which may lead to multiple attempts to place the needle that may result in pain and possibly an incomplete or failed nerve block. The use of ultrasound (US) to guide peripheral and central neuraxial blocks has improved both accuracy and safety in both adults and children. In this chapter, the basic principles of US imaging and the techniques of US-guided regional anesthesia (USGRA) in children are described and reviewed.





  • 44 Acute Pain
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Benjamin J. Walker, David M. Polaner, Charles B. Berde

    The management of acute pain in children continues to evolve. Numerous observational and self-report assessment tools have been validated in children, but a complete assessment also includes information about adverse effects, sleep quality, and functional recovery. In cognitively-impaired children, information from caregivers can be extremely helpful in addition to specific assessment tools for these children. There are unique aspects of assessment and risk factors for opioid-related respiratory depression in these children, who will benefit from an individualized analgesic plan. Initial treatment of pain should use multimodal principles, including non-pharmacologic methods, such as distraction, and opioid-sparing analgesics. In most cases, scheduled administration of non-opioids (e.g., acetaminophen, NSAIDS) is recommended, with opioids given as needed for moderate to severe pain. In addition to standard oral and intravenous routes, opioids can also be delivered via patient-controlled analgesia in older children or by proxy (nurse or family member) in younger or cognitively-impaired children. Regional anesthesia techniques are another important part of a multimodal approach, and are particularly useful after major surgery. Epidural (or paravertebral) catheters are appropriate for major thoracic, abdominal or lower extremity operations. Peripheral approaches to the brachial plexus or femoral and sciatic nerves can be used for operations involving upper or lower extremities, and children can be discharged home with continuous peripheral catheters in place. Adjuvants such as clonidine or dexamethasone can be given to prolong the duration of the regional blockade.





  • 45 Chronic Pain
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Robert Baker, Alexandra Szabova, Kenneth Goldschneider

    Chronic pain is a sometimes debilitating problem for children and young adults. The emphasis in evaluation and treatment is based on a multidisciplinary care model. Anesthesiologists may be asked about advanced pharmacologic treatments, interventional techniques and may have to care for patients on chronic opioids or other pharmacotherapies. Further, anesthesia providers covering an acute pain service may receive consultation requests for patients having acute flare-ups of chronic pain. An understanding of the multi-team approach to management of these children is essential, as is also knowledge of disease processes, pain pharmacotherapy and complementary therapies.





  • 46 Anesthesia Outside the Operating Room
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Joseph P. Cravero, Mary Landrigan-Ossar

    Anesthesia outside the operating room for children is a critical aspect of the delivery of pediatric anesthesia. The very nature of children requires that anesthesia is provided for procedures and tests outside the operating room to an extent that far outstrips that needed for adult patients. The variety of practice environments involved in this care places a premium on the resourcefulness and flexibility of the anesthesiologist. The myriad of comorbid conditions that accompany these patients must be appreciated—particularly those that impact airway management as well as cardiac and pulmonary performance. Anesthesiologists should seek to create systems of care that provide an environment that allows maximum efficiency and safety for this patient population regardless of the location of anesthesia. These systems require appropriate personnel and equipment availability that allows care to be consistent with the standards of the operating room, including the management of difficult airways and cardiopulmonary arrest. Quality Improvement efforts must be specifically designed for anesthesia delivered outside the operating room and must be integrated with the departments that are partnered in this care. Finally, anesthesia outside the operating room has to be delivered by individuals with specific knowledge of the idiosyncrasies of each location in which care is delivered. The special precautions that must be taken in the magnetic environment of the MRI scanner, the peculiar sclerotic agents in the interventional radiology suite, and the risks associate with radiation therapy, must all be appreciated and considered in designing care plans in each of these important ancillary environments.





  • 47 The Postanesthesia Care Unit and Beyond
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Andreas H. Taenzer, Jeana E. Havidich

    A critical segment of the perioperative care of children is the transfer from the operating room to the staffed post anesthesia care unit (PACU). A well designed, fully equipped, and appropriately staffed PACU is essential for providing high quality and safe care. This chapter emphasizes the importance of vigilant monitoring and discusses common occurring events, the perioperative environment, and strategies to provide optimal care for children in the postoperative period.





  • 48 Sedation for Diagnostic and Therapeutic Procedures Outside the Operating Room
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Joseph P. Cravero, Richard F. Kaplan, Mary Landrigan-Ossar, Charles J. Coté

    Sedation of children for tests and procedures represents a significant portion of the care that pediatric anesthesiologists provide. At the same time, other pediatric subspecialists also provide sedation services for which pediatric anesthesiologists provide back-up and oversight. The manner in which sedation is divided between anesthesiologists and other specialists is not consistent between institutions and must be decided based on patient need and the availability of individuals who are qualified to provide sedation. To aid in standardization, sedation guidelines have been promulgated by multiple organizations with the objective of bringing the same rigorous standards for evaluation, monitoring, documentation, and quality improvement to the practice of sedation that has characterized anesthesiology care. Sedation outcomes are generally improved when this care is provided in an organized system of care in which the sedation providers, administrators, nurses, and technical support have well understood protocols for scheduling cases, induction/maintenance of sedation, and recovery/discharge. The unique challenge of sedation lies in providing safe and effective service while working in a multitude of locations, each with unique challenges. Sedation providers must be aware of the requirements of each venue such as the pain and repeated procedures that characterize oncology procedures or the strong magnetic field of the MRI scanner. Care must be designed that meets the needs of the patient and the individual who is performing the procedure. In order to optimize sedation provision, an extensive knowledge of the pharmacokinetics and pharmacodynamics of the sedative and analgesic agents is critical.





  • 49 Procedures for Vascular Access
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Samuel H. Wald, Julianne Mendoza, Frederick G. Mihm, Charles J. Coté

    This chapter describes the various common locations for venous access, central venous access and arterial catheter placement in infants and children. Possible complications associated with each approach are also delineated. Several intraosseous techniques are also illustrated. Videos of ultrasound guided access and many illustrations help the reader to understand best practices.





  • 51 Pediatric Anesthesia in Developing Countries
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Adrian T. Bösenberg

    Historically the funding focus in the developing world has been on primary healthcare and infectious diseases. Access to safe surgery and safe anesthesia has recently been identified as a global health issue. Anesthesia remains a forgotten specialty. The challenges facing an anesthesiologist include lack of adequate training—many anesthetics are provided by nonphysicians—understaffing, poorly maintained equipment, outdated drugs and unreliable water, oxygen and electrical supplies. Children often present with comorbidities or complications of the surgical disease challenging the anesthesiologist. This chapter offers suggestions to prepare the anesthesiologist to meet these challenges.





  • 52 Pediatric Equipment
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Patrick A. Ross, Jerrold Lerman, Charles J. Coté

    This chapter covers the spectrum of equipment used to provide anesthesia to children safely. Specifically, advantages and disadvantages of devices for warming the child, maintaining temperature, intravenous catheter types and issues, fluid and blood warming devices, airway adjuncts (laryngeal mask airways, oral airways, and nasal trumpets), equipment for intubation, anesthesia workstations, waste gas scavenging, humidification systems, capnography (both sidestream and mainstream), pulse oximetry (and oximetry engineering approaches to improve accuracy and additional information such as hemoglobin estimate or the presence of abnormal hemoglobins [e.g., carboxyhemoglobin]), reflectance oximetry and near-infrared spectroscopy, neuromuscular blockade monitors, processed EEG monitors (bispectral index, entropy, and others, particularly in infants and young children), as well as a detailed assessment of a multitude of continuous and intermittent cardiac output measurement devices are discussed. The noninvasive continuous cardiac output devices are likely to be standard of care in the near future. When purchasing new equipment, it is vital that the equipment is tested in the environment where it will be used and by the practitioners intended to use it.





  • 53 Simulation in Pediatric Anesthesia
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Christine L. Mai, Demian Szyld, Jeffrey B. Cooper

    The field of pediatric anesthesia has become increasingly subspecialized, with unique challenges that demand high-quality teaching and training. Pediatric anesthesia is focused in detail, diverse in surgical and technical complexity, and tolerates an exceedingly small margin for error. With the growth and increased sophistication of pediatric anesthesia, as well as the regionalization of specialty care, anesthesiologists are continually challenged to gain and maintain expertise in the safe and effective delivery of routine and emergency pediatric anesthesia. Simulation-based education provides an experiential learning paradigm for opportunities to improve medical knowledge, technical skills, communication, and decision-making skills for common as well as rare events. In addition, simulation education provides opportunities to assess systems-based problems, improve interdisciplinary team training, ease relocation into facilities, and help adapt to new equipment and technology. Within the past decade, there has been rapid progress and growth of simulation in health care training for purposes of improving patient safety and quality of care. Given that crises in pediatric anesthesia are relatively rare and unpredictable and that anesthesia residents and faculty are expected to be able to successfully manage these situations, simulation-based education can fill these important knowledge gaps. In this chapter, we review how simulation education is applied in pediatric anesthesiology by describing its uses for learning and training in residency and fellowship programs, and its applications to improve patient safety and patient care.





  • Index
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children









  • Video Contents
    25 juin 2018
    Publication date: 2019
    Source:Aesthetic Surgery Techniques









  • 2 Aesthetic Medicine
    25 juin 2018
    Publication date: 2019
    Source:Aesthetic Surgery Techniques

    Author(s): Jaffer Khan, Zara Yousufzai, Natasha Jaffer Khan








 

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  • An explicit method for simulating non-Gaussian and non-stationary stochastic processes by Karhunen-Loève and polynomial chaos expansion
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): Hongzhe Dai, Zhibao Zheng, Huihuan Ma

    A new method is developed for explicitly representing and synthesizing non-Gaussian and non-stationary stochastic processes that have been specified by their covariance function and marginal cumulative distribution function. The target process is firstly represented in the Karhunen-Loève (K-L) series form, the random coefficients in the K-L series is subsequently decomposed using one-dimensional polynomial chaos (PC) expansion. In this way, the target process is represented in an explicit form, which is particularly well suited for stochastic finite element analysis of structures as well as for general purpose simulation of realizations of these processes. The key feature of the proposed method is that the covariance of the resulting process automatically matches the target covariance, and one only needs to iterate the marginal distribution to match the target one. Three illustrative examples are used to demonstrate the proposed method.





  • Analytical lump model for the nonlinear dynamic response of bolted flanges in aero-engine casings
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): Marc-Antoine Beaudoin, Kamran Behdinan

    Bolted flanges in aero-engine casings exhibit a nonlinear response when subjected to forced vibration. The current models for the structural dynamic analysis of bolted flanges are accurate, but they are cumbersome for the design of new structures. These models either require model updating from modal testing, or they require a large number of nonlinear elements. This study presents a new lump model that accounts for the nonlinear phenomena of partial clearance and friction, and has analytical parameters related to the flange geometry. The model was implemented in finite element analysis and compared with an experiment where a test structure is excited by an electromechanical shaker. The lump model predicts the structural response better than a traditional linear method; yet it does not require model updating, and it uses a very limited number of nonlinear elements. The model is therefore well suited for the early design phase of new aero-engine casings. This study supports the use of geometric lump models in the field of nonlinear structural dynamics.





  • Vibration feature evolution of locomotive with tooth root crack propagation of gear transmission system
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): Zaigang Chen, Wanming Zhai, Kaiyun Wang

    As the prompt development of modern railway transportation towards high-speed and high load-capacity, the high-power locomotive is urgently required. Under this situation, the wheel–rail dynamic interaction is becoming more and more intensified which will deteriorate the vibration condition of the key elements of locomotive, such as the gear transmissions. Once gear failures are present, such as gear tooth crack or breakage, it is likely to threaten the operation safety of the locomotive. Thus, deep insight into the fault features of the locomotive gear transmission is urgently necessary for prevention of the induced disastrous consequences. This paper is concentrated on the fault vibration feature extraction of a locomotive in presence of gear tooth root crack under the complicated dynamic excitations from both the gear transmissions and the nonlinear wheel–rail interactions. The locomotive–track coupled dynamics model considering the dynamic effect of the mechanical power transmission path is employed, and the time-varying mesh stiffness of the gear pair with tooth root crack fault and the rail geometric irregularities are then incorporated into the dynamics model to obtain the vibration responses. Then, angular synchronous average technique is proposed to enhance the fault vibration features, and the statistical indicators extracted in frequency domain are developed to reveal the evolution law for the crack propagation scenarios along crack depth or tooth width. The analyzed results indicate that the angular synchronous average technique could effectively reveal the fault vibration feature, and the M8A in the selected statistical indicators is most sensitive to the tooth crack propagation in frequency domain.





  • Structural scaling factor identification from output-only data by a moving mass technique
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): Yongding Tian, Jian Zhang, Yixuan Han

    Ambient vibration testing is a convenient and cost-effective alternative to impact testing as it doesn’t require artificial excitation devices and traffic control. The lack of input force measurement in ambient vibration testing, however, does impede the identification of structural scaling factors, which are extremely important for Frequency Response Functions (FRFs) estimation and flexibility identification. A moving mass technique of identifying structural scaling factors from output-only data is proposed in this article. By this method, a vehicle passing over a bridge is regarded as a moving mass with spatial and time variation on the structure, inducing a vehicle-bridge system with time-varying modal properties. Theoretical derivation will be performed to identify scaling factors from the measured vibration responses of the bridge with and without the moving vehicle. Magnitudes of FRFs and the structural flexibility matrix can be obtained once the scaling factors are identified. The proposed method delivers comparable results to impact testing but is considerably more convenient. Numerical and experimental examples are studied to verify the effectiveness of proposed method. The effects of vehicle speed, mass value and measurement noise are also investigated.





  • Internal model control for reduction of bias and harmonic currents in hybrid magnetic bearing
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): Xiangbo Xu, Jinhao Liu, Shao Chen

    Bias and harmonic currents, which are caused by rotor gravity, mass imbalance and sensor runout, are the dominant disturbances of the hybrid magnetic bearing (HMB) systems. To reject these disturbances and realize the low power control, a novel internal model control method based on positive current feedback and repetitive control is proposed. The positive current feedback can tune the levitation position of the rotor adaptively so that the rotor gravity can be supported precisely by the force resulting from the permanent magnet in the HMB. To suppress the harmonic currents caused by the mass imbalance and sensor runout, a novel plug-in repetitive controller is proposed. Compared to the conventional repetitive controller, the low-pass filter is removed from the internal time lag loop outside so as to improve the system stability and reduce the elimination error of the high-order current harmonics. The absolute stability of the whole closed-loop system is analyzed by using the Nyquist criterion to the time-delay system with the help of the regeneration spectrum method. Upon the phase-frequency characteristic, phase compensators in low, middle, and high frequencies are designed, respectively. Both simulations and experiments are carried out to demonstrate the validity of the proposed control method.





  • Dynamic response of laminated composites using design of experiments: An experimental and numerical study
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): Luiz Fernando dos Santos Souza, Dirk Vandepitte, Volnei Tita, Ricardo de Medeiros

    In addition to many advantages, composite materials constitute a new challenge in many industrial fields and applications. Vibration Based Methods (VBM) are relatively simple and at low cost to detect damage and fails in composite structures, but they are sensitive to variations in geometry and material properties. Recently, the main challenge in VBM is to establish a robust process to be applied on an industrial environment. In this work, a methodology to identify the effect of design parameters on the dynamic response of laminated composite plates is presented. For the case of composite materials, the production process plays an important role. Numerical dynamic analyses are run using the Finite Element code ABAQUS™ which is complemented with user subroutines written in Fortran and Python. A Design of Experiments (DoE) strategy is developed to reduce the number of experiments and to evaluate the effect of the design parameters. Two sets of composite plates were evaluated, [0]8 and [0/−15/15/0/−15/15]s, with natural frequencies used as response quantities. In addition, Frequency Response Functions are analyzed, as they are obtained by a full factorial design. Afterwards, the results are discussed with proper attention for the potential and for the limitations of the proposed methodology from the perspective of usage to detect damage and failure in composite structures.





  • Transmission-error frequency-domain-behavior of failing gears
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): William D. Mark, Aaron C. Isaacson, Matthew E. Wagner

    Failing gear teeth, either by working-surface-damage (pitting, spalling, scuffing, etc.) or by bending fatigue, causes tooth-to-tooth variations in the loaded tooth working surfaces. Such variations cause changes (generally increases) in the non-tooth-meshing rotational-harmonic amplitudes of the transmission-error contribution from the affected gear. Simple models of missing working-surface material caused by damage are used to show where transmission-error rotational-harmonic spectrum changes will take place. Bending fatigue damage is shown to initially cause maximum changes in rotational-harmonic amplitudes well below the tooth-meshing fundamental harmonic, whereas small pits are shown to cause changes in higher-frequency rotational-harmonic amplitudes. Good agreement is shown between an experimentally obtained rotational-harmonic spectrum caused by tooth-surface damage and that predicted from damage measured on the failing teeth. Substantial increases in high-frequency rotational-harmonic amplitudes are shown to be expected from gear teeth undergoing significant plastic deformation in late stages of bending-fatigue failure. Accurate assessment of damage contributions using before-damage non-negligible rotational-harmonic amplitudes (sideband harmonics, etc.) are shown to suggest use of complex rotational-harmonic amplitudes.





  • Optimal design of a piezo-actuated 2-DOF millimeter-range monolithic flexure mechanism with a pseudo-static model
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): Mingxiang Ling, Junyi Cao, Zhou Jiang, Minghua Zeng, Qisheng Li

    Flexure-based displacement amplifiers are frequently used to magnify the small stroke of piezoelectric actuators. In this paper, a hybrid rhombus-lever multistage displacement amplifier with an improved boundary constraint is proposed to develop a parallel millimeter-range XY monolithic mechanism while retaining a relatively high dynamic frequency. A concise pseudo-static model developed by the authors is utilized to analyze the kinetostatic and dynamic performances of the designed flexure mechanism and then the geometric parameters are optimized in terms of both kinetostatics and dynamics. Different from the previous Lagrange-based dynamic methods for compliant mechanisms, cumbersome calculations of the kinetic and elastic energies as well as adopting Lagrange’s equation are all avoided. With the proposed pseudo-static model, the kinetostatics and dynamics of the flexure mechanism can be analyzed concurrently in a programmed statics-similar way, suggesting its superiority for fast performance prediction and parameter optimization during the early stage of design. Finally, a prototype of the XY monolithic mechanism is manufactured and experimentally tested for evaluating its performances. Experimental results show that the designed flexure mechanism has a motion range in excess of 1.2 mm × 1.2 mm with a resonance frequency of 128 Hz. The cross-coupling error is measured to be less than 2%, indicating an acceptable decoupling performance.





  • Improving energy harvesting from random excitation by nonlinear flexible bi-stable energy harvester with a variable potential energy function
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): Zhiyong Zhou, Weiyang Qin, Wenfeng Du, Pei Zhu, Qi Liu

    In this paper, aim at improving the performance of bi-stable energy harvester (BEH), we proposed a flexible bi-stable energy harvester (FBEH). The FBEH is composed of two elastic beams: one is the piezoelectric cantilever beam with a tip magnet and the other is the clamped-clamped beam with a mid-magnet. The dynamic behavior of FBEH was studied, and the results show that the FBEH owning a variable potential energy function is beneficial for snap-through. The governing equations of FBEH are derived by energy principles. Then its dynamic response under random excitation was studied. The results prove that the FBEH not only has a smaller threshold for snap-through, but also can generate a larger power output for the excitation intensity larger than the critical one. Validation experiments were designed and carried out. The experimental results are in good agreement with the simulation ones.





  • The influence of out-of-band modes in system inversion
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): K. Maes, G. Lombaert

    Model-based system inversion is a technique which allows reconstructing the forces applied to a structure and the corresponding system response using data obtained from a limited number of sensors and a dynamic model of the structure. Very often, modally reduced order models are used in system inversion, hereby reducing the number of modes to reduce the computational cost. This paper shows that the model order reduction can lead to large estimation errors in model-based system inversion. These errors are due to the disregarded quasi-static contribution of the out-of-band modes. Existing techniques for quasi-static correction cannot be straightforwardly adopted in the state-space models which are commonly applied in recursive system inversion. This paper therefore presents a novel computationally efficient approach where the quasi-static contribution of the disregarded modes is accounted for in the state-space model by means of dummy modes. The presented approach is validated using data obtained from a full-scale experiment on a footbridge. The results show that the proposed correction of the model significantly increases the estimation accuracy, as can be seen from the significant reduction in the error on the estimated forces.





  • Output torque modeling of control moment gyros considering rolling element bearing induced disturbances
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): Hong Wang, Qinkai Han, Daning Zhou

    Control moment gyros (CMG) have been widely used in spacecraft attitude control and large angle slewing maneuvers over the years. Understanding and suppressing high-frequency disturbances in CMG’s output torques is a crucial factor to achieving the desired level of payload performance. Output torque modeling of a single gimbal CMG (SGCMG) with nonlinear rolling bearing supports is conducted in this paper. Taking the installation errors and micro-vibrations of the flywheel into account, three axis output torques of a SGCMG are derived based on Newton-Euler approach and theorem of moment of momentum. Dynamic model is then constructed to obtain the micro-vibration responses of the rotary flywheel. Mass imbalances of the flywheel, flexibility of supporting structures and nonlinearity induced by one pair of angular contact ball bearings are considered in the dynamic model. Especially for the rolling bearing, an improved load distribution analysis is proposed to more accurately obtain the contact deformations and angles between the rolling balls and raceways. Various factors, including the preload condition, surface waviness, Hertz contact and elastohydrodynamic lubrication, are included in the analysis. The bearing restoring forces are then obtained through iteratively solving the load distribution equations at every time step. Dynamic tests on a typical SGCMG supported by angular contact ball bearings are conducted to verify the output torque model. The effects of flywheel dynamic/static eccentricities, inner/outer surface waviness amplitudes, bearing axial preload and installation skew angles on the dynamic output torques are discussed. The obtained results would be useful for the optimal design and vibration control of the SGCMG system.





  • A new bivariate dimension reduction method for efficient structural reliability analysis
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): Jun Xu, Chao Dang

    This paper presents a new bivariate dimension reduction method (BDRM) for statistical moments evaluation and structural reliability analysis with accuracy and efficiency. A high-order unscented transformation (HUT) is introduced to evaluate the two-dimensional integrals involved in BDRM, and the free parameter involved in HUT is suggested. In this regard, the proposed BDRM can be formulated accordingly for statistical moments assessment. Then, the performance function’s probability density function (PDF) is reconstructed by the shifted generalized lognormal distribution (SGLD) with the available statistical moments as constraints. Thus, the failure probability can be straightforwardly obtained by a simple integral over the PDF. The proposed method is verified by five numerical examples, including linear and non-linear, explicit and implicit performance functions. Besides, some other existing methods are also employed to demonstrate the advantages of the proposed method. It is found that the proposed method can keep the trade-off of accuracy and efficiency for structural reliability analysis.





  • A non-probabilistic time-variant reliable control method for structural vibration suppression problems with interval uncertainties
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): Lei Wang, Xiaojun Wang, Yunlong Li, Juxi Hu

    Active control techniques are necessary to structural vibration problems and thus studies of controller design are particularly important in mechanical dynamic engineering. Because parametric deviations due to inherent nature or external excitation are inevitable and can severely influence the final performance of real control systems, optimal active control considering uncertainty is gradually becoming a major concern in modern theory fields. In this paper, a novel non-probabilistic time-variant reliability-based optimization (NTRBO) strategy is presented for closed-loop controller design of vibration reduction issues. First, boundary rules and auto-correlation characteristics of controlled responses are confirmed based on the state-space transformation and the interval process approach. Then, enlightened by models of the first passage and the safety factor (SF), a new definition of the time-variant reliability measurement is provided. As keys to construct the optimal controller, weighing matrices in the Riccati equation are finally determined by solving the developed NTRBO model. The validity and the feasibility of the proposed methodology are demonstrated by several example applications, and the results reveal that uncertainty factors in optimal active control can be addressed from a new time-variant reliability perspective.





  • Identification and analysis of nonlinear dynamics of inertial actuators
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): Mattia Dal Borgo, Maryam Ghandchi Tehrani, Stephen John Elliott

    This paper presents an experimental study of the nonlinear dynamics of electrodynamic proof mass actuators. When inertial actuators are used in velocity feedback controllers, their nonlinear dynamics can affect the stability margin of the feedback loop. Thus, it is crucial to identify the nonlinearity sources and to build reliable models that can be implemented in the stability analysis. Firstly, the underlying linear model parameters of an inertial actuator are identified for small excitation signals. The inductance losses at high frequencies due to eddy currents have also been included in the electrical impedance model. Secondly, the nonlinear model of the inertial actuator is determined using the detection, characterisation and identification process. Finally, a numerical analysis is carried out to highlight the implications of nonlinear dynamics of inertial actuators. The proposed methodology is applied to several electromagnetic proof mass actuators, including when the proof mass is not accessible to be directly instrumented.





  • Flux measurement and conditioning system for heteropolar active magnetic bearing using Kapton-foil Hall sensors
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): Arkadiusz Mystkowski, Andrzej Kierdelewicz, Rafal P. Jastrzebski, Egidijus Dragašius, Darius Eidukynas

    This paper addresses the problem of measuring the electromagnetic flux in the air gap of the active magnetic bearing (AMB) without mechanical structure modifications. The designed and fabricated flux measurement and conditioning system based on the ultra-thin flexible Kapton-foil Hall sensors (developed by IFW Dresden Institute for Integrative Nanosciences) and signal amplifiers are presented. The flexible sensors are directly mounted on the curved surfaces of stator poles of the AMB and measure flux density in the AMB air gap. Then, the measurement itself and the conditioning system are verified in different measuring conditions of the heteropolar radial AMB with the air gap width of 0.4 mm. The measurement results were used in identifying crucial rotor flux-AMB system parameters. The proposed direct flux measurement system is successfully verified in the designed test rig in the presence of rotor position disturbances or coil current oscillation. The advantages and drawbacks of the presented measurement setup are discussed.





  • Design multi-stopband laminate acoustic metamaterials for structural-acoustic coupled system
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): X. Xiao, Z.C. He, Eric Li, A.G. Cheng

    This paper designs the laminate acoustic metamaterials with multi-stopband for structural-acoustic coupled system. The laminate acoustic metamaterials are composed of carbon-fiber-reinforced polymer (CFRP) and a periodic array of two degrees of freedom (2-DOF) mass-spring-damper subsystems attached to the laminate. According to the dispersion analysis, two stopbands are observed around the absorbers’ resonant frequency. Based on the finite element modeling, the multi-stopband behavior has been confirmed. In addition, the effects of damping of vibration absorbers are discussed in this work. By adding the appropriate damping to the vibration absorbers, the two stop bands can be combined into a wider stopband. Subsequently, the analyses of multi-stopband laminate acoustic metamaterials in the structural–acoustic coupled system are performed. The excellent performance of multi-stopband laminate acoustic metamaterials has been applied to the front panel of vehicle, and the noise of passenger compartment cavity is reduced significantly.





  • Non-linear analysis of a quarter-car model with stroke-dependent twin-tube shock absorber
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): Jan Łuczko, Urszula Ferdek

    The work presents results of the analysis of a quarter-car model with a modified twin-tube hydraulic shock absorber. In comparison with a classical damper, this shock absorber possesses an additional double-chamber cylinder. The flow of oil into these chambers is controlled by relative displacement of the auxiliary piston and by pressure difference in the adjacent chambers. The introduced nonlinear spring element – bumper – protects the shock absorber against damage in the case of large amplitudes of excitations. Performance efficiency of the shock absorber model within the range of both large amplitudes and high excitation frequencies ensures that the change of the oil bulk modulus resulting from a change in pressure is accounted for. The introduction of additional chambers into the shock absorber leads to a change in the characteristics of the damping force. Within the range of small amplitudes and high frequencies the system acts like a shock absorber with a soft characteristic, which improves the driving comfort. In resonance ranges the increase in the damping force ensures higher driving safety. The analysis of the system response to the harmonic excitation of variable frequency and amplitude as well as to the random excitation permits to examine the impact of excitation parameters and construction parameters on the indicators characterizing the driving comfort and safety. The results of numerical simulations are illustrated with the graphs of time histories, spectral analyses, characteristics of the damping force, and others, illustrating the processes of controlling oil flow.





  • Experimental study of the variations in the electromechanical properties of piezoelectric energy harvesters and their impact on the frequency response function
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): Patricio Peralta, Rafael O. Ruiz, Viviana Meruane

    This work presents a comprehensive study of the uncertainties involved in the Frequency Response Function (FRF) of Piezoelectric Energy Harvesters (PEHs) based on experimental results. A proper experimental setup is designed facilitating the FRF identification for different PEHs. The test protocol consists in three test that quantify the aleatoric and epistemic uncertainties by the study of repeated measurements, variation in the mounting process, and variations in the electromechanical properties of the materials employed in the harvester. The experimental setup and the test protocol are tested employing two different bimorph-type harvesters identified as Model A and B. 20 harvesters corresponding to Model A and 10 to Model B are tested multiples times under the test protocol proposed. Results clearly indicate that the most important source of uncertainties deals with the variability of the electromechanical properties of the PEH, which is particularly greater than: (i) the noise on the measurements, (ii) the variations introduced by the clamping condition, and (iii) the dimensional variations in the geometry. The results are also compared with predictions performed by adopting a recent numerical framework to propagate uncertainties in PEHs. The present work is particularly important since it presents the experimental evidence of the variations in the electromechanical properties of PEH and their influence on the FRF. Additionally, the results not only validate the uncertainty propagation procedures previously proposed but also suggest that their use is mandatory to estimate the FRF. This work presents, to the best of the authors’ knowledge, the first effort to experimentally quantify the uncertainties in PEHs.





  • Parameter selection for model updating with global sensitivity analysis
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): Zhaoxu Yuan, Peng Liang, Tiago Silva, Kaiping Yu, John E. Mottershead

    The problem of selecting parameters for stochastic model updating is one that has been studied for decades, yet no method exists that guarantees the ‘correct’ choice. In this paper, a method is formulated based on global sensitivity analysis using a new evaluation function and a composite sensitivity index that discriminates explicitly between sets of parameters with correctly-modelled and erroneous statistics. The method is applied successfully to simulated data for a pin-jointed truss structure model in two studies, for the cases of independent and correlated parameters respectively. Finally, experimental validation of the method is carried out on a frame structure with uncertainty in the position of two masses. The statistics of mass positions are confirmed by the proposed method to be correctly modelled using a Kriging surrogate.





  • Innovative Hybrid Mass Damper for Dual-Loop Controller
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): S. Chesné, G Inquieté, P. Cranga, F. Legrand, B. Petitjean

    The paper presents a new dual transducer and its associated control law. It aims to increase the efficiency of a traditional passive damped electromagnetic resonator by controlling its mass response actively. The design aspects of the so-called Dual-Loop Controller (DLC) for Hybrid Mass Damper (HMD) are presented and discussed. The control law attempts to modify a Tuned Mass Damper (TMD) to use it as an Active Mass Damper (AMD), with the objective of combining the best of the two technologies by actively increasing the performance of the passive device. Based on an optimally tuned passive device, the resulting system is fail-safe. The conception of the new dual transducer used as an HMD, designed specifically for this control law, is detailed. The hybrid device is experimentally validated both on a laboratory setup and on a real helicopter.





  • Hybrid interval and random analysis for structural-acoustic systems including periodical composites and multi-scale bounded hybrid uncertain parameters
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): Ning Chen, Siyuan Xia, Dejie Yu, Jian Liu, Michael Beer

    For the response analysis of periodical composite structural–acoustic systems with multi-scale uncertain-but-bounded parameters, a bounded hybrid uncertain model is introduced, in which the interval variables and the bounded random variables exist simultaneously. In the periodical composite structural–acoustic system, the equivalent macro constitutive matrix and average mass density of the microstructure are calculated through the homogenization method. On the basis of the conventional first-order Taylor series expansion, a homogenization-based hybrid stochastic interval perturbation method (HHSIPM) is developed for the prediction of periodical composite structural–acoustic systems with multi-scale bounded hybrid uncertain parameters. By incorporating the Gegenbauer polynomial approximation theory into the homogenization-based finite element method, a homogenization-based Gegenbauer polynomial expansion method (HGPEM) is also proposed to calculate the bounds of expectation and variance of the sound pressure response. Numerical examples of a hexahedral box and an automobile passenger compartment are given to investigate the effectiveness of the HHSIPM and HGPEM for the prediction of periodical composite structural–acoustic systems with multi-scale bounded hybrid uncertain parameters.





  • Experimental study on dynamic behavior of ball bearing cage in cryogenic environments, Part I: Effects of cage guidance and pocket clearances
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): Bokseong Choe, Jeonkook Lee, Doyoung Jeon, Yongbok Lee

    In cryogenic environments, it is not possible to apply oil or grease to ball bearings, owing to the extreme temperature conditions. Thus, polytetrafluoroethylene (PTFE) cages are used as solid lubricants in such environments, because PTFE has a low coefficient of friction. PTFE cages increase the rotational stability of the ball bearings by reducing the frictional force of the rolling elements. In addition, design parameters such as the cage guidance and ball-pocket clearances significantly affect the stability of the ball bearings. In this study, the dynamic behavior of a ball bearing cage submerged in a cryogenic fluid was investigated for different cage clearances and rotation speeds. For experimental verification, a test rig was designed to realize a cryogenic environment. The test rig could be driven to 11,000 rpm using a DC motor and provided loads of up to 20 kN using a pneumatic cylinder. A metal ring was employed to measure the cage whirling amplitude using a fiber optic displacement sensor. The parameters considered included the cage whirling amplitude, ball bearing torque, and cage wear. The effects of the clearances and rotation speed on the cage stability and performance were analyzed using the probability density function of the cage whirling frequency, and the standard deviation of this function decreased as the outer guidance clearance decreased. In addition, the cage wear loss increased with decreasing cage ball-pocket clearance, owing to the collisions between the balls and cage pocket. The experimental results agreed partially with the existing theory and demonstrated that the cage instability increased as the cage guidance clearance increased.





  • Multibody model of railway vehicles with weakly coupled vertical and lateral dynamics
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): Sergio Muñoz, Javier F. Aceituno, Pedro Urda, José L. Escalona

    In the field of railroad dynamics, multibody models used for on-board state observation, parameter identification and track geometry measurement must ensure a high computational efficiency, particularly when real-time simulations are required. In this paper, a simplified model based on the assumption of weakly coupled lateral and vertical dynamics is proposed. Generalized forces included in the equations of motion are obtained using symbolic computations and the wheel-rail contact is modeled using knife-edge contact constraints and the concept of equivalent conicity. Resulting contact constraint equations can be solved analytically allowing the solution of ODE equations of motion in terms of independent coordinates. This general model considers arbitrary-geometry tracks including rail centerline irregularities. With the aim of showing the accuracy of the proposed model for the simulation of railways vehicle dynamics, a comparative study with a full 3D coupled dynamic model has been carried out for different vehicles and track geometries. The comparative study shows that the proposed simplified model in this work provides acceptable results for many applications. The model greatly improves the computational effort and it is applicable to real-life situations requiring a reduced set of parameters.





  • H∞/extension stability control of automotive active front steering system
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): WanZhong Zhao, MiLi Fan, ChunYan Wang, Zhilin Jin, Yufang Li

    In order to solve the contradiction between the control output and the control effect, especially in extreme conditions, this paper designs a H/extension controller based on active front steering system by introducing the extension control into H mixed sensitivity control about sensitivity function S/T problem. The proposed controller can transform the control information under the unstable domain into the eligible value range by using dependent degree to tune the control output. And ultimately, the combination of H norm and extension transformation extends the stable region of the system. The results of the simulation and vehicle test show that the proposed H/extension controller can effectively deal with the contradiction between the control effect and the control output under extreme condition, and achieve satisfactory control effect with the control output as small as possible under normal condition.





  • A updating method using strain frequency response function with emphasis on local structure
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): Ning Guo, Zhichun Yang, Le Wang, Xin Bian

    A dynamic finite element model updating method for the concerned local structure is presented using strain frequency response function test data. Firstly, a dynamic condensation technique is developed to establish the dynamic finite element model of the concerned local structure for improving the analytical efficiency of the dynamic strains and their transfer relations in model updating. Then, the sensitivity of strain frequency response function of the local structure is conducted to construct the canonical equation for model updating. Furthermore, a model updating strategy of ‘grouping-iteration’ is proposed to stabilize the ill-posed problem in the model updating process. Finally, numerical simulation and experimental investigation for updating the dynamic finite element model of the cantilever plate structure with elastic support are performed to validate the feasibility and efficiency of the present method. The obtained results show that the present method can be successfully used to update the dynamic finite element model of the local structure in terms of achieving a good agreement between the strain frequency response functions of the updated finite element model and the actual structure.





  • An improved technique for measuring piston-assembly friction and comparative analysis with numerical simulations: Under motored condition
    25 juin 2018
    Publication date: 15 January 2019
    Source:Mechanical Systems and Signal Processing, Volume 115

    Author(s): Congcong Fang, Xianghui Meng, Youbai Xie, Chengwei Wen, Ruichao Liu

    Robust and accurate measurement techniques are essential to studying the piston-assembly friction of Internal Combustion (IC) engines. Based on the instantaneous Indicated Mean Effective Pressure (IMEP) method, this paper develops an improved measurement technique to evaluate the piston-assembly friction in engines. Wireless telemetry technology is employed in the measurement of connecting rod axial force, which greatly minimizes the engine modifications and enhances the measurement stability compared to the conventional wired way. The measurement system, which is composed of computer, data acquisition system, sampling trigger apparatus and sensors, is exploited with special attention given to the sampling synchronization of signal channels including cylinder pressure, connecting rod force and crank angle position. Engineering implementations are carried out on a four-stroke gasoline engine under motored condition. The measurement results are compared with numerical results from a newly developed numerical coupling model system, and it shows that the two agree well. In addition, the piston-assembly friction under different engine speeds and inlet lubricant temperatures are also measured, and analyses indicate that these results are in good correlation with the well-known Stribeck curve. This improved measurement technique provides an accurate and reliable option for the friction evaluation of piston-assembly components in engine designs.

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  • 7 Pharmacokinetics and Pharmacology of Drugs Used in Children
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Brian J. Anderson, Jerrold Lerman, Charles J. Coté

    The pharmacokinetics (PK) and pharmacodynamics (PD) of most medications in children especially neonates, differ from those in adults. Children exhibit different PK and PD from adults because of their immature renal and hepatic function, different body composition, altered protein binding, distinct disease spectrum, diverse behavior, and dissimilar receptor patterns. PK differences necessitate modification of the dose and the interval between doses to achieve the desired concentration associated with a clinical response and to avoid toxicity. In addition, some medications may displace bilirubin from its protein binding sites and possibly predispose to kernicterus in premature neonates. Drug effect may be influenced by altered capacity of the end organ, such as the heart or bronchial smooth muscle, to respond to medications in children compared with adults. In this chapter we discuss basic pharmacologic principles as they relate to drugs commonly used by anesthesiologists.





  • 14 The Pediatric Airway
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): John E. Fiadjoe, Ronald S. Litman, Julia F. Serber, Paul A. Stricker, Charles J. Coté

    This chapter reviews the developmental anatomy and physiology of the pediatric upper airway as it relates to the practice of pediatric anesthesia. Differences between the pediatric and adult airways are important determinants of anesthetic techniques. Knowledge of normal developmental anatomy and physiologic function is required to understand and manage both the normal and the pathologic airways of infants and children. Techniques of mask ventilation, oral and nasal airway placement, use of supraglottic devices, and tracheal intubation are reviewed for normal and anatomically abnormal pediatric patients.





  • 16 Essentials of Cardiology
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Wanda C. Miller-Hance, Ralph Gertler

    Congenital heart disease (CHD) is the most common birth defect affecting approximately 1% of live births. Although CHD is the leading cause of neonatal mortality, advances over the last several decades including significant contributions related to anesthesia care, now allow for survival of most affected infants. The wide spectrum of congenital cardiovascular anomalies and the various types of acquired heart disease in the pediatric age group presents a challenge to the clinician who does not specialize in the care of these children. Even for those with a focus or interest in cardiovascular disease, the range of structural defects, myocardial disorders, and other conditions, and the varied associated hemodynamic perturbations can be overwhelming. The ability to provide optimal perioperative care to affected children heavily relies on a clear understanding of the basic pathophysiology of the congenital anomalies and acquired diseases, familiarity with the commonly used diagnostic modalities in cardiology and their clinical applications, and medical and surgical treatment options available to affected individuals. In this chapter, we present essential concepts in cardiology to enhance the overall knowledge of the practicing anesthesiologist in pediatric cardiovascular disease.





  • 32 Orthopedic and Spine Surgery
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Niall C. Wilton, Brian J. Anderson

    Anesthesia for orthopedic and spine surgery provides a multitude of challenges. Children often present with concomitant diseases that affect cardiovascular and respiratory function. Operating times can be protracted, particularly for scoliosis surgery. Many of these procedures involve children already severely compromised by muscle weakness and impaired respiratory function. Improvement in monitoring of spinal cord function help minimize neurological risk. Significant blood loss can occur that requires strategies for blood product management and transfusion reduction. Major trauma causing orthopedic injuries invariably involves other organ systems that may adversely interact with or compromise anesthesia management. The risks of pulmonary aspiration of gastric contents and the requisite fasting times, after even minor trauma involving an isolated forearm fracture, continue to be debated. Fat embolus is uncommon in children with long-bone fractures but should be considered in any child with hypoxia and altered consciousness in the perioperative period. Tumor surgery may be complicated by chemotherapy, altered drug disposition, or bone grafting considerations akin to those for plastic and reconstructive surgery and complex postoperative pain management may be required. Positioning children on the operating table involves care, especially for those with limb deformities and contractures. Patients with a variety of syndromes also require other orthopedic procedures to assist in minimizing the impact of those syndromes on their quality of life. These syndromes present their own unique anesthetic challenges. The anesthesiologist's role facilitating surgery and providing optimal postoperative care, particularly pain management, should not be underestimated.





  • 41 Malignant Hyperthermia
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Jerrold Lerman, Jerome Parness

    Malignant hyperthermia (MH) is a pharmacogenetic disease that is the sole life-threatening disease triggered by inhaled anesthetics and succinylcholine. Identification of the signs and symptoms of an acute MH reaction (the first sign is an increased end-tidal carbon dioxide partial pressure) has been instrumental in establishing diagnostic tests and treatments. The caffeine-halothane contracture test remains the gold-standard test to diagnose MH against which the more recent genetic testing is compared. The primary mutation associated with MH to date is the ryanodine receptor defect on chromosome 19, which is an important gatekeeper for calcium release from the sarcoplasmic reticulum. Several other genetic mutations have also been associated with MH. The diminution in mortality from MH over the past several decades has been attributed to appreciating the signs of an acute MH reaction and the availability of dantrolene. The pharmacokinetics of dantrolene have been delineated in children to guide treatment. MH has been associated with several muscle disorders (e.g., central core myopathy) and shares characteristics with others (e.g., heat stroke). Monitoring of those who develop MH reactions should continue until all signs of MH have abated. Preparation of AWSs for MHS patients includes replacing the carbon dioxide absorbent, airway breathing circuit and flushing the AWS while the ventilator is active for at least 10 minutes and most recently, insertion of charcoal filters in the breathing circuit. All patients who develop MH reactions should be counseled regarding muscle biopsy testing (if adults) and referred for a MedicAlert bracelet.





  • 43 Ultrasound-Guided Regional Anesthesia
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Manoj K. Karmakar, Wing H. Kwok

    Peripheral nerve blocks are frequently performed in children to provide anesthesia or analgesia during the perioperative period. Success depends on the ability to accurately place the needle—and thereby the local anesthetic—close to the target nerve without causing injury to the nerve or adjacent structures. In the past, clinicians relied on anatomic landmarks, fascial clicks, loss of resistance, or nerve stimulation to position the needle in the vicinity of the nerve. Anatomic landmarks provide valuable clues to the position of the nerve, but they are surrogate markers, lack precision, vary among children of different ages, and may be difficult to locate in obese children. Even nerve stimulation, which has been recommended as the gold standard for nerve localization, may not always elicit a motor response and its use does not guarantee success or preclude complications. Moreover, the accuracy of needle placement cannot be predicted with any of these methods, which may lead to multiple attempts to place the needle that may result in pain and possibly an incomplete or failed nerve block. The use of ultrasound (US) to guide peripheral and central neuraxial blocks has improved both accuracy and safety in both adults and children. In this chapter, the basic principles of US imaging and the techniques of US-guided regional anesthesia (USGRA) in children are described and reviewed.





  • 45 Chronic Pain
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Robert Baker, Alexandra Szabova, Kenneth Goldschneider

    Chronic pain is a sometimes debilitating problem for children and young adults. The emphasis in evaluation and treatment is based on a multidisciplinary care model. Anesthesiologists may be asked about advanced pharmacologic treatments, interventional techniques and may have to care for patients on chronic opioids or other pharmacotherapies. Further, anesthesia providers covering an acute pain service may receive consultation requests for patients having acute flare-ups of chronic pain. An understanding of the multi-team approach to management of these children is essential, as is also knowledge of disease processes, pain pharmacotherapy and complementary therapies.





  • 52 Pediatric Equipment
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Patrick A. Ross, Jerrold Lerman, Charles J. Coté

    This chapter covers the spectrum of equipment used to provide anesthesia to children safely. Specifically, advantages and disadvantages of devices for warming the child, maintaining temperature, intravenous catheter types and issues, fluid and blood warming devices, airway adjuncts (laryngeal mask airways, oral airways, and nasal trumpets), equipment for intubation, anesthesia workstations, waste gas scavenging, humidification systems, capnography (both sidestream and mainstream), pulse oximetry (and oximetry engineering approaches to improve accuracy and additional information such as hemoglobin estimate or the presence of abnormal hemoglobins [e.g., carboxyhemoglobin]), reflectance oximetry and near-infrared spectroscopy, neuromuscular blockade monitors, processed EEG monitors (bispectral index, entropy, and others, particularly in infants and young children), as well as a detailed assessment of a multitude of continuous and intermittent cardiac output measurement devices are discussed. The noninvasive continuous cardiac output devices are likely to be standard of care in the near future. When purchasing new equipment, it is vital that the equipment is tested in the environment where it will be used and by the practitioners intended to use it.





  • Index
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children









  • 2 Materials Science
    25 juin 2018
    Publication date: 2019
    Source:Atlas of Orthoses and Assistive Devices

    Author(s): Thomas R. Lunsford, Bill Contoyannis

    Great advancements for patients requiring orthoses, prostheses, and assistive technology have occurred because of the broad range of materials that have become available to the practitioner over the last century. The ability to custom fabricate devices with intricate precision has improved the fit of devices. Materials with high strength-to-weight ratios have meant the devices are lighter, and materials that flex without failure have improved the function and performance that can be achieved.





  • 3 Principles of Fabrication
    25 juin 2018
    Publication date: 2019
    Source:Atlas of Orthoses and Assistive Devices

    Author(s): Terry J. Supan

    Orthoses are either custom made by the orthotist or they are generic devices fabricated in a range of sizes. The techniques used to produce traditional metal and leather orthoses and thermoplastic orthoses have not changed. What has changed is where these devices are fabricated and whether they are custom made for the individual patient or mass-produced generic devices, which are either modified to fit the patient or simply placed on the patient. Because of the advancements in both data collection and software development, computer-aided design (CAD) and computer-aided manufacturing (CAM), including additive manufacturing (3D printing), for orthoses has increased. Despite numerous advances in materials and fabrication techniques, the most critical element in the creation of a well-fitted, highly functional orthosis remains the clinical judgment and technical skill of the orthotist treating the patient.





  • 4 Principles of Normal and Pathologic Gait
    25 juin 2018
    Publication date: 2019
    Source:Atlas of Orthoses and Assistive Devices

    Author(s): Joseph B. Webster, Benjamin J. Darter

    Human gait is a complex phenomenon that involves intricate interactions between the pelvis, hips, knees, and ankles. The goal of normal human ambulation is to facilitate travel from one location to another while minimizing effort and maintaining adequate stability across a wide variety of walking conditions. This is made possible by complex interactions between central and peripheral neural pathways coordinating movement of the musculoskeletal system. Understanding human gait requires a solid knowledge of underlying physiology and biomechanical principles. Observational gait analysis skills are essential in the evaluation and management of gait deviations seen in individuals with disabling conditions. Comprehending the relationship between clinical examination findings, biomechanical influences, and gait pattern observations serves as the foundation for the appropriate prescription and fitting of lower limb orthoses.





  • 5 Biomechanics of the Spine
    25 juin 2018
    Publication date: 2019
    Source:Atlas of Orthoses and Assistive Devices

    Author(s): Olivier Y. Rolin, William E. Carter







  • 6 Principles and Components of Spinal Orthoses
    25 juin 2018
    Publication date: 2019
    Source:Atlas of Orthoses and Assistive Devices

    Author(s): Justin L. Weppner, Alan P. Alfano

    Numerous orthotic devices are available for the treatment of spinal injury or instability. Custom devices are required for patients with atypical dimensions or significant bony prominences, where the intimacy of fit is best accommodated by custom-molded contours. Custom contours are especially indicated when high corrective forces are applied through the device for the treatment of spinal deformities such as scoliosis. In cases of spinal injury, general immobilization is required across the involved segment(s) of the spine. Typically, this patient population presents with relatively “normal” contours of the spine and torso before injury. In cases of spinal injury, the acute nature of the injury necessitates rapid treatment. Internal spinal fixation techniques have advanced significantly, and in some cases, these enhanced techniques preclude the need for additional external stabilization. In response to these developments, several manufacturers now provide reasonably priced prefabricated devices that are functionally equivalent to custom designs. However, these devices differ in material selection and durability. The choice of a prefabricated device is often mediated by physician preference. Regardless of the device selected for treatment of the spine, the choice of a custom or prefabricated orthosis will be determined by the level(s) of injury and the amount of stabilization required and must be determined on a case-by-case basis. It is important that a complete, clear, and acceptable plan is created by a multidisciplinary treatment team and that the treatment plan reflects the patient's goals, guided by the treatments team's expertise.





  • 9 Orthoses for Spinal Trauma and Postoperative Care
    25 juin 2018
    Publication date: 2019
    Source:Atlas of Orthoses and Assistive Devices

    Author(s): Natasha Romanoski, Shannon Schultz, David R. Gater

    The primary goal of a spinal orthotic is to increase spinal stability in all anatomical planes to support immobilization. Secondary goals include limiting progression of deformity and providing stability for healing. When determining a treatment plan after spinal trauma, the team must first define spinal stability to determine the risk of neurologic compromise. For some stable vertebral fractures, nonoperative treatment may be a reasonable alternative to surgery, achieving comparable long-term results as the use of spinal orthotics. For an unstable fracture requiring surgical intervention, spinal orthotics can be considered in the postoperative phase. The scientific evidence regarding whether spinal orthotics should be used after a spinal trauma and postoperative care varies widely based on the anatomical location of the injury, fracture type, stability, mechanism of injury, intended outcome, and individual comorbidity.





  • 15 Orthoses for the Burned Hand
    25 juin 2018
    Publication date: 2019
    Source:Atlas of Orthoses and Assistive Devices

    Author(s): Brian M. Kelly, Tanya Berenz, Tiffany Williams

    Rehabilitation of a burned hand is challenging, and successful rehabilitation begins early after the acute injury. In general, scar contractures are the primary cause of deformities in the burned hand. Failure to address them early will lead to permanent joint and ligament contractures. Treatment of these deformities is much more difficult than preventing them. Proper splinting and edema control are the mainstays of early rehabilitative efforts. Initiation of range-of-motion (ROM) exercises is based upon the severity of injury and an assessment of the relative risks of tendon rupture and benefits derived by exercise. After the acute period, treatment consists of continued compliance with therapy, appropriate splinting, and use of compression garments to prevent contraction and hypertrophic scars. Prevention of deformity and restoration of optimal hand function must be the principal goals of rehabilitative efforts.





  • 16 Orthotic Treatment Considerations for Arthritis and Overuse Syndromes in the Upper Limb
    25 juin 2018
    Publication date: 2019
    Source:Atlas of Orthoses and Assistive Devices

    Author(s): Christopher Hovorka, Daniel Acker

    The chapter reviews the basic pathophysiology, pathomechanics, and orthotic treatment considerations of persons with arthritis and overuse syndromes involving the upper limb. The most common forms of arthritis (rheumatoid arthritis and osteoarthritis) and most common forms of overuse syndromes (lateral epicondylitis, cubital tunnel syndrome, carpal tunnel syndrome, de Quervain tenosynovitis, trigger finger [stenosing tenosynovitis]) are reviewed. Each of the pathologic conditions and diagnoses are reviewed by anatomical level (elbow, wrist, hand, thumb, fingers) and magnitude of deformity (mild, moderate, and severe). Using this framework, the orthotic treatment considerations are then presented in a practical and clinically relevant manner to guide the busy practitioner in making evidence-based decisions. Topics covered include orthosis design considerations (i.e., force systems, biomechanical motion controls, limb alignment, limb–orthosis interface dynamics and fitting principles) that are critical to enabling the patient with highly disabling conditions to achieve desired functional goals.





  • Introduction
    25 juin 2018
    Publication date: 2019
    Source:Atlas of Orthoses and Assistive Devices

    Author(s): Douglas P. Murphy







  • 18 Biomechanics of the Hip, Knee, and Ankle
    25 juin 2018
    Publication date: 2019
    Source:Atlas of Orthoses and Assistive Devices

    Author(s): Barry Meadows, Roy Bowers







  • 24 Orthoses in Total Joint Arthroplasty
    25 juin 2018
    Publication date: 2019
    Source:Atlas of Orthoses and Assistive Devices

    Author(s): Erik Hansen, Gregory Jason Golladay

    Total joint arthroplasty is one of the most common surgical interventions in orthopedics. For patients with disabling arthritis of the hip or knee, joint replacement typically results in significant improvement in mobility and quality of life. Though orthoses are not typically used after primary total joint arthroplasty, bracing is sometimes necessary to preemptively support the joint when nerve blocks are used for anesthesia or after complicated primary or revision surgeries. More commonly, orthoses are used in the management of postoperative complications such as dislocation. This chapter discusses the common indications for use of an orthosis in total joint arthroplasty surgery.





  • 25 Knee Orthoses for Sports-Related Issues
    25 juin 2018
    Publication date: 2019
    Source:Atlas of Orthoses and Assistive Devices

    Author(s): Rondy Michael Lazaro, Katherine L. Dec

    Injuries to various structures of the knee joint, including the ligaments, menisci, and patellofemoral components, compose a significant portion of sports-related injuries seen by health care providers and compromise a patient's knee joint function and stability. Knee orthoses have been used in each step of the sport performance process, such as injury minimization, ligament rehabilitation after reconstruction, and treatment of functional instability of the knee joint. The knee joint allows for flexion and extension with some degree of translation and axial rotation. Shear forces act upon the knee during gait and in weight-bearing tasks. Proper functioning of knee braces must take into account these biomechanical factors. Both prefabricated (“off-the-shelf”) and custom-made knee brace designs have proven effective, and each has benefits with cost, fit, weight, and material components. More recently, braces have been manufactured with composite lightweight materials, such as carbon fiber and aluminum. Athletes have used knee orthoses both to prevent medial collateral ligament (MCL) and anterior cruciate ligament (ACL) injury and to protect ACL-deficient knees or an ACL-reconstructed graft while returning to full activity. Knee braces have become an important component in functional rehabilitation programs for treatment of MCL sprains. Acute grade I and II posterior cruciate ligament (PCL) tears have been shown to heal with bracing, protected weight bearing, and quadriceps muscle rehabilitation. Braces are now used in osteoarthritis to enhance function and reduce pain.





  • 26 Orthotic Management of Neuropathic and Dysvascular Feet
    25 juin 2018
    Publication date: 2019
    Source:Atlas of Orthoses and Assistive Devices

    Author(s): Omkar Baxi, Michael Yeranosian, Anthony Lin, Maximilian Munoz, Sheldon Lin

    Neuropathic and dysvascular feet can present challenges to the treating orthopedic surgeon and should be managed by a multidisciplinary team focusing on patient education and prevention of injury. The most common pathology revolves around diabetic complications and development of the Charcot neuropathic joint. Neuropathic ulcers need to be prevented with diligent care, because ulceration is prognostic for amputation in these patients. The goal of treatment for these patients is to maintain a viable limb that can support weight bearing and ambulation with an off-the-shelf orthosis. The first stage of treatment for neuropathic ulceration typically consists of a total contact cast, which allows off-loading of the affected area to promote wound healing. Once healing has started, the patient can be transitioned to off-loading orthotics such as an orthotic dynamic splint or, classically, the Charcot Restraint Orthotic Walker (CROW). After wounds are completely healed, future injuries can be prevented with appropriately fitting shoewear and accomodative inserts. Ulcers and wounds caused by venous vascular disease may benefit from treatment with compressive stockings, whereas wounds caused by arterial deficiency require consultation with a vascular surgeon for appropriate treatment.





  • 27 Orthotic Management of Polio and Postpolio Syndrome
    25 juin 2018
    Publication date: 2019
    Source:Atlas of Orthoses and Assistive Devices

    Author(s): William Lovegreen, Michael Kwasniewski, Preeti Panchang, Marcus J. Smith

    Postpolio syndrome (PPS) presents a challenge in management for both health care providers and orthotists. Although polio has effectively been eradicated in the developed world as a result of vaccination, PPS is a late and debilitating sequela of the acute viral infection. A diagnosis of exclusion, PPS presents with onset of new weakness after at least 15 years of functional and neurologic stability and leads to a flaccid paralysis while maintaining intact sensation and proprioception. In this group of individuals, fatigue is often the most common complaint, even with minimal exertion. These patients will often compensate well for their debility and may sometimes find it difficult to accept a new assistive device. To date, no medications have been found to be significantly beneficial in the management of polio or PPS. Optimization of cardiorespiratory function and proper orthotic management are both essential in the management of PPS. Patients are best treated with an individualized, multidisciplinary rehabilitation approach following a customized medical and functional evaluation to address the unique deficits of each individual with polio or PPS. Many different orthotics are available to aid in the management of PPS, but for them to be effective, they must be used by the patient. Therefore before the fitting process is initiated, it is crucial to discuss and understand the goals and expectations of the patient when using an orthosis or AD to improve compliance and avoid setting unrealistic expectations.





  • 28 Lower Limb Orthoses for Persons Who Have Had a Stroke
    25 juin 2018
    Publication date: 2019
    Source:Atlas of Orthoses and Assistive Devices

    Author(s): Joan Hou, Benjamin D. Fortson, William Lovegreen, John R. Fox

    Lower limb orthoses are a useful part of the rehabilitative effort for an individual who has suffered a stroke. Orthotic treatments should be based on clearly identified objectives and the unique physical examination of each patient for best chance of success. Off-the-shelf orthoses have some value, particularly when a patient's strength and range of motion are likely to change in the future, but custom orthoses offer the most options for control or accommodation of a lower limb. Current research is interesting, but there remain many areas for investigation, particularly in formation of treatment guidelines, validation of outcome measures, and analysis of biomechanical effects of orthotic intervention.








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  • 32 Orthopedic and Spine Surgery
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Niall C. Wilton, Brian J. Anderson

    Anesthesia for orthopedic and spine surgery provides a multitude of challenges. Children often present with concomitant diseases that affect cardiovascular and respiratory function. Operating times can be protracted, particularly for scoliosis surgery. Many of these procedures involve children already severely compromised by muscle weakness and impaired respiratory function. Improvement in monitoring of spinal cord function help minimize neurological risk. Significant blood loss can occur that requires strategies for blood product management and transfusion reduction. Major trauma causing orthopedic injuries invariably involves other organ systems that may adversely interact with or compromise anesthesia management. The risks of pulmonary aspiration of gastric contents and the requisite fasting times, after even minor trauma involving an isolated forearm fracture, continue to be debated. Fat embolus is uncommon in children with long-bone fractures but should be considered in any child with hypoxia and altered consciousness in the perioperative period. Tumor surgery may be complicated by chemotherapy, altered drug disposition, or bone grafting considerations akin to those for plastic and reconstructive surgery and complex postoperative pain management may be required. Positioning children on the operating table involves care, especially for those with limb deformities and contractures. Patients with a variety of syndromes also require other orthopedic procedures to assist in minimizing the impact of those syndromes on their quality of life. These syndromes present their own unique anesthetic challenges. The anesthesiologist's role facilitating surgery and providing optimal postoperative care, particularly pain management, should not be underestimated.





  • 45 Chronic Pain
    25 juin 2018
    Publication date: 2019
    Source:A Practice of Anesthesia for Infants and Children

    Author(s): Robert Baker, Alexandra Szabova, Kenneth Goldschneider

    Chronic pain is a sometimes debilitating problem for children and young adults. The emphasis in evaluation and treatment is based on a multidisciplinary care model. Anesthesiologists may be asked about advanced pharmacologic treatments, interventional techniques and may have to care for patients on chronic opioids or other pharmacotherapies. Further, anesthesia providers covering an acute pain service may receive consultation requests for patients having acute flare-ups of chronic pain. An understanding of the multi-team approach to management of these children is essential, as is also knowledge of disease processes, pain pharmacotherapy and complementary therapies.





  • 13 Upper Limb Orthoses for the Stroke- and Brain-Injured Patient
    25 juin 2018
    Publication date: 2019
    Source:Atlas of Orthoses and Assistive Devices

    Author(s): Christopher C. Duncan, Steven R. Edgley

    Stroke and brain injury are often complicated by the development of upper motor neuron syndrome. Most spontaneous motor recovery occurs within 6 months of stroke and traumatic brain injury. Combining the therapeutic interventions of oral antispasmodics, therapy, casting, bracing, and targeted chemodenervation is a first-line measure. Definitive surgical procedures to reduce spasticity are effective and include neurectomies, tendon releases, and transfers. It is important to treat the underlying spasticity to use orthoses effectively. The prolonged period of spontaneous neurologic recovery is complicated by spasticity (resistance to quick stretch), rigidity (resistance to slow stretch), impairment of motor control, synergistic patterns of movement, synkinesis (involuntary associated movement in a distant limb segment), and immobility. Orthotic selection heavily depends on the patient's realistic functional goals as well as the severity, type, and distribution of joint range of motion impairment. It is a compromise of immobilization versus function meant to restore normative biomechanics to the upper limb.





  • 14 Upper Limb Orthoses for Persons With Spinal Cord Injuries and Brachial Plexus Injuries
    25 juin 2018
    Publication date: 2019
    Source:Atlas of Orthoses and Assistive Devices

    Author(s): Jeffrey T. Tubbs, Dawne Pound

    Orthotics and assistive devices are commonly used in the management of individuals with a spinal cord injury (SCI) or brachial plexus injury (BPI) and provide functional benefits to users. Although orthotic interventions are a common and widely accepted clinical practice, minimal research data exist to support their effectiveness. As with the entire rehabilitation process after SCI and BPI, no one therapy technique or orthotic intervention should stand alone. Orthoses, stretching and strengthening programs, medications, and surgical options should all be considered during both the acute and chronic phases of rehabilitative care.





  • 16 Orthotic Treatment Considerations for Arthritis and Overuse Syndromes in the Upper Limb
    25 juin 2018
    Publication date: 2019
    Source:Atlas of Orthoses and Assistive Devices

    Author(s): Christopher Hovorka, Daniel Acker

    The chapter reviews the basic pathophysiology, pathomechanics, and orthotic treatment considerations of persons with arthritis and overuse syndromes involving the upper limb. The most common forms of arthritis (rheumatoid arthritis and osteoarthritis) and most common forms of overuse syndromes (lateral epicondylitis, cubital tunnel syndrome, carpal tunnel syndrome, de Quervain tenosynovitis, trigger finger [stenosing tenosynovitis]) are reviewed. Each of the pathologic conditions and diagnoses are reviewed by anatomical level (elbow, wrist, hand, thumb, fingers) and magnitude of deformity (mild, moderate, and severe). Using this framework, the orthotic treatment considerations are then presented in a practical and clinically relevant manner to guide the busy practitioner in making evidence-based decisions. Topics covered include orthosis design considerations (i.e., force systems, biomechanical motion controls, limb alignment, limb–orthosis interface dynamics and fitting principles) that are critical to enabling the patient with highly disabling conditions to achieve desired functional goals.





  • 27 Orthotic Management of Polio and Postpolio Syndrome
    25 juin 2018
    Publication date: 2019
    Source:Atlas of Orthoses and Assistive Devices

    Author(s): William Lovegreen, Michael Kwasniewski, Preeti Panchang, Marcus J. Smith

    Postpolio syndrome (PPS) presents a challenge in management for both health care providers and orthotists. Although polio has effectively been eradicated in the developed world as a result of vaccination, PPS is a late and debilitating sequela of the acute viral infection. A diagnosis of exclusion, PPS presents with onset of new weakness after at least 15 years of functional and neurologic stability and leads to a flaccid paralysis while maintaining intact sensation and proprioception. In this group of individuals, fatigue is often the most common complaint, even with minimal exertion. These patients will often compensate well for their debility and may sometimes find it difficult to accept a new assistive device. To date, no medications have been found to be significantly beneficial in the management of polio or PPS. Optimization of cardiorespiratory function and proper orthotic management are both essential in the management of PPS. Patients are best treated with an individualized, multidisciplinary rehabilitation approach following a customized medical and functional evaluation to address the unique deficits of each individual with polio or PPS. Many different orthotics are available to aid in the management of PPS, but for them to be effective, they must be used by the patient. Therefore before the fitting process is initiated, it is crucial to discuss and understand the goals and expectations of the patient when using an orthosis or AD to improve compliance and avoid setting unrealistic expectations.





  • 29 Assessment and Orthotic Management of Gait Dysfunction in Individuals With Traumatic Brain Injury
    25 juin 2018
    Publication date: 2019
    Source:Atlas of Orthoses and Assistive Devices

    Author(s): Alberto Esquenazi, Mukul Talaty







  • 30 Congenital and Acquired Disorders
    25 juin 2018
    Publication date: 2019
    Source:Atlas of Orthoses and Assistive Devices

    Author(s): Jason Edinger, Amit Sinha, Mark Fisher







  • 40 Communication Devices and Electronic Aids to Activities of Daily Living
    25 juin 2018
    Publication date: 2019
    Source:Atlas of Orthoses and Assistive Devices

    Author(s): Melissa Oliver

    Assistive technology (AT) is a generic term that includes assistive, adaptive, and rehabilitative devices for people with disabilities and includes the process used in selecting, locating, and using them. This chapter reviews the AT evaluation process that includes the interdisciplinary team determination of the appropriateness of, selection of, and training for an AT device. Through the evaluation process, AT practitioners use the Human Activity Assistive Technology (HAAT) Model to assess the human factors, activities of participation, and the context (environment) in which the individual will use the technology. The AT field covers a wide range of strategies and devices; this chapter focuses on two areas of AT: (1) alternative and augmentative and alternative communication (AAC) devices and (2) the electronic aids to daily living (EADLs). Factors that determine the selection of an AAC and EADL device and the types of devices available are explored. In addition, critical points in the selection process such as access, mounting, and the integration of the technology are explored. Finally, funding sources and the future of AT in the field of AACs and EADLs are identified.





  • 43 Neuromuscular Electrical Stimulation Applications
    25 juin 2018
    Publication date: 2019
    Source:Atlas of Orthoses and Assistive Devices

    Author(s): Jayme S. Knutson, Nathaniel S. Makowski, Kevin L. Kilgore, John Chae

    Neuromuscular electrical stimulation (NMES) of paralyzed muscles can be used to restore or replace motor function in individuals who have upper motor neuron damage from causes such as stroke or spinal cord injury (SCI). In some conditions, such as stroke or incomplete SCI, NMES may be part of a therapy regimen that helps restore volitional movement and function. In other conditions, such as severe stroke or complete SCI, permanent NMES applications are needed to replace the lost neuromuscular function. This chapter describes NMES devices for upper and lower extremity therapeutic and neuroprosthetic applications.





  • Index
    25 juin 2018
    Publication date: 2019
    Source:Atlas of Orthoses and Assistive Devices









  • 55 Scleroderma–Systemic Sclerosis
    25 juin 2018
    Publication date: 2019
    Source:Clinical Immunology

    Author(s): John Varga, Fredrick M. Wigley

    Systemic sclerosis is an orphan disease of unknown cause and complex pathogenesis. Multiple genetic variants that are common to systemic lupus, and other autoimmune diseases have been identified. Autoimmunity and fibrosis are prominent features of the disease. Systemic sclerosis predominantly affects women, follows a chronic and unpredictable course with multiple organs affected, and lacks effective disease-modifying therapies. In addition to variable degree of skin involvement and Raynaud phenomenon, interstitial lung disease, widespread microvascular disease, intestinal tract pathology, and cardiovascular complications are common. Late-stage disease is usually accompanied by ischemic digital ulcers, pulmonary artery hypertension, pulmonary fibrosis, and small bowel dysfunction. The diffuse cutaneous form of the disease is associated with increased mortality. Although there are no approved disease-modifying therapies, carefully tailored and individualized management of specific organ-based complications can be highly effective in improving quality of life, reducing complications, and improving outcomes.





  • 56 Inflammatory Muscle Diseases
    25 juin 2018
    Publication date: 2019
    Source:Clinical Immunology

    Author(s): Arash H. Lahouti, Lisa Christopher-Stine

    The idiopathic inflammatory myopathies (IIMs) are a group of rare systemic diseases. They consist of polymyositis (PM), dermatomyositis (DM), inclusion body myositis (IBM), and more recently described immune-mediated necrotizing myopathy. Traditionally, they are believed to be autoimmune diseases, although recent studies suggest that there is a close resemblance between IBM and other neurodegenerative diseases. Similar to other autoimmune diseases, patients with IIM often have autoantibodies in their serum. Some of these antibodies are specific for myositis and are not seen in other rheumatic disorders. Our knowledge of the myositis-specific antibodies is not comprehensive. Over the past few years, there has been considerable effort to better characterize antibodies associated with myositis, and new antibodies are being discovered constantly. Each myositis-specific antibody is closely linked to a unique clinical phenotype. Thus these antibodies are useful in classifying the IIMs. They can forewarn physicians of particular extramuscular manifestations and guide them toward initiating appropriate treatments. The IIMs present with muscle weakness and elevated muscle enzymes. In patients with DM, skin manifestations may be the initial presentation. The differential diagnosis of the IIMs is broad and includes drug-induced myopathies, neuromuscular disorders, muscular dystrophies, and metabolic and endocrine myopathies. To add to the complexity of the classification, some DM patients do not develop muscle weakness, referred to as clinically amyopathic DM. The age and gender of the patient, the pattern of the weakness, the severity of the manifestations, and the associated symptoms usually aid in suspecting the correct diagnosis. For example, IBM is distinguished from other IIMs by a characteristic involvement of the finger flexor and knee extensor muscles, which is often asymmetrical. IBM is more common in older men, whereas PM and DM are commonly seen in young to middle-aged women and children. Dermatomyositis is often associated with characteristic skin findings, which are not a feature of PM and IBM. However, differentiation between the IIMs cannot be made on clinical grounds in a substantial number of patients, and further diagnostic testing is required. For example, both PM and immune-mediated necrotizing myopathy present in a same fashion with a predominant symmetrical proximal muscle weakness and elevated muscle enzymes. They can be distinguished only by pathological examination. On muscle biopsy, immune-mediated necrotizing myopathy is associated with necrosis and regeneration of muscle fibers and a characteristic sparse inflammatory infiltrate. In contrast, PM is associated with the presence of cytotoxic inflammatory cells surrounding and invading muscle fibers. Electromyography is a valuable tool for differentiating between weakness originating from muscle rather than peripheral nerves. Magnetic resonance imaging (MRI) can be extremely helpful to identify inflammatory changes in patients with subtle clinical muscle involvement. Moreover, MRI can help to better estimate the burden of the disease and differentiate acute changes (edema) from chronic changes (atrophy). The role of new imaging modalities such as whole-body MRI needs to be further investigated. Interstitial lung disease, gastrointestinal involvement, and arthritis are among the most common extramuscular manifestations of the IIMs. Interstitial lung disease commonly occurs as part of the antisynthetase syndrome in a subset of patients who have antisynthetase autoantibodies. Gastrointestinal manifestations include dysphagia and aspiration pneumonia. Dysphagia is particularly common and can be seen in all forms of the IIM. In addition, certain forms of the IIMs, particularly DM, can be a paraneoplastic phenomenon. The most common cancers associated with myositis include gynecological (ovarian), pulmonary, gastrointestinal (pancreatic, stomach, and colorectal), and non-Hodgkin lymphoma. Also, the IIMs may be associated with other autoimmune diseases such as systemic lupus erythematosus, Sjögren syndrome, and systemic sclerosis. Muscle biopsy is critical for the diagnosis of IIMs. The presence of perifascicular atrophy is strongly suggestive of DM, whereas the finding of rimmed vacuoles in the appropriate context suggests IBM. Muscle biopsy may also help differentiate between the IIMs and other forms of myopathy presenting as myositis clinical mimics such as drug-induced myopathies and muscular dystrophies. Treatment of the IIMs is based largely on experience. Corticosteroids remain the mainstay of treatment. Steroid-sparing agents such as azathioprine, methotrexate, mycophenolate mofetil, and hydroxychloroquine are frequently initiated at presentation while a steroid taper is attempted. In patients with refractory disease, rituximab, intravenous immunoglobulin, and biological medications may be tried. Inclusion body myositis is the most resistant subset of the IIMs.





  • 65 Myasthenia Gravis
    25 juin 2018
    Publication date: 2019
    Source:Clinical Immunology

    Author(s): Arnold I. Levinson

    Myasthenia gravis (MG) is an autoimmune disease characterized by weakness of striated muscles. The weakness is caused by impaired neuromuscular transmission resulting from a reduction in the number of receptors for the neuromuscular type of nicotinic acetylcholine receptor (nAChR) at the postsynaptic myoneural junction. In most cases, this reduction is the result of the action of IgG antibodies directed at the α subunit of the nAChR. However, it is now appreciated that additional autoantibodies may be found in the presence and absence of anti-AChR antibodies, some of which have associated pathogenic activity. Most of these react with other components of the muscle endplate. Several subtypes of MG are recognized based on their clinical presentation, age of onset of MG, and associated autoantibody specificities. The diagnosis of MG can usually be confirmed by pharmacological and electrophysiological testing, along with identification of anti-AChR antibodies or one of the other less commonly associated muscle-specific autoantibodies. Considerable knowledge concerning the immunopathogenesis of MG has been garnered from studies of an experimental model of MG, experimental autoimmune MG (EAMG). These studies have highlighted the potential roles of a number of immunoregulatory disturbances that are linked to a bevy of associated genetic risk factors. However, this model falls short in recapitulating a major clinicopathological feature of its human counterpart; that is, thymic pathology is absent. Indeed, thymic pathology is a frequent feature of human MG with 65–75% of patients with anti-AChR antibodies presenting with thymic hyperplasia/germinal center formation and another 10% of patients with thymoma. In addition, it is generally accepted that thymectomy leads to clinical improvement. Accordingly, for years considerable attention has been focused on the mechanisms by which thymic events occurring in genetically predisposed individuals might lead to the development of MG. Although this important issue remains to be clarified, it is likely, at least in the patients with thymic hyperplasia, that an antecedent inflammatory reaction in the thymic medulla leads to a breach in immunological tolerance with spillover of the autoimmune response to skeletal muscle. Therapy typically entails the use of drugs that directly target the abnormal neuromuscular transmission and immunomodulatory agents and procedures that target the pathogenic immune responses.





  • 73 Sarcoidosis
    25 juin 2018
    Publication date: 2019
    Source:Clinical Immunology

    Author(s): Edward S. Chen, David R. Moller

    Sarcoidosis is a systemic inflammatory disorder characterized by noncaseating granulomas and CD4 lymphocyte inflammation in affected tissues. The disease most frequently involves lungs and thoracic lymph nodes, although any organ system may be involved. The manifestations and clinical course of sarcoidosis vary greatly. There is a genetic predisposition for sarcoidosis risk and course that predominantly involves major histocompatibility complex (MHC)–associated genes. Immunological features include polarized T-helper 1 (Th1) and Th17 immunity at sites of inflammation associated with deficient regulatory T-cell (Treg) responses. There is evidence for microbial triggers in the etiology of sarcoidosis but a lack of consensus on the ensuing pathogenic pathways. A diagnosis of sarcoidosis is best established by the presence of compatible clinical features, consistent biopsy results, and the exclusion of other causes of granulomatous inflammation. More than one-third of patients experience chronic, progressive manifestations requiring maintenance suppressive therapy. Corticosteroid therapy remains the cornerstone of treatment. Steroid-sparing therapies are often used, although their role remains uncertain.





  • Index
    25 juin 2018
    Publication date: 2019
    Source:Clinical Immunology









  • Answers
    25 juin 2018
    Publication date: 2019
    Source:Clinical Immunology









  • Chapter 3 Development of the Vestibular System and of Balance Function
    25 juin 2018
    Publication date: 2019
    Source:Dizziness and Vertigo Across the Lifespan

    Author(s): Robert O’Reilly, Thierry Morlet, Chris Grindle, Emily Zwicky, Erin Field

    Vestibular function is present at birth and is gradually modulated by developing central inhibitory influences, cerebellar control, visual development, and central vestibular adaptation until it reaches maturity at approximately 15years of age. Children do not commonly complain of dizziness or vestibular dysfunction; therefore, the diagnosis relies on careful questioning of the child (if applicable) and parents, targeted imaging/testing, and an astute clinician to synthesize findings into a cohesive diagnosis. Abnormal responses in children require clarification to distinguish whether the locus of the problem rests primarily with the vestibular system, the vestibular pathways, or with abnormalities in visual, motor, or proprioceptive systems that jointly contribute to the acquisition of motor milestones. With a careful history and appropriate vestibular and balance testing, it is frequently possible to identify the likely cause of the balance disorder, even in the most complex patients.





  • Chapter 4 Assessment Techniques for Vestibular Evaluation in Pediatric Patients
    25 juin 2018
    Publication date: 2019
    Source:Dizziness and Vertigo Across the Lifespan

    Author(s): L. Maureen Valente

    The study of vestibular disorders in children has gained popularity over recent years. This chapter thoroughly describes the adaptation of adult techniques so that pediatric patients may be successfully evaluated. Assessment tools include strategies that may be implemented more informally during the medical/physical examination and more formal evaluative techniques, including videooculography, rotary chair, computerized dynamic posturography, vestibular evoked myogenic potentials, and others. It is crucial that the clinician obtains pediatric normative data, as opposed to comparing pediatric evaluative results with adult normative data. As with hearing impairment, the earlier a vestibular disorder is identified, the earlier the necessary remediation strategies may begin.





  • Index
    25 juin 2018
    Publication date: 2019
    Source:Dizziness and Vertigo Across the Lifespan









  • Index
    25 juin 2018
    Publication date: 2019
    Source:Fundamentals of Cognitive Neuroscience









  • Advances in multi-sensor fusion for body sensor networks: Algorithms, architectures, and applications
    25 juin 2018
    Publication date: January 2019
    Source:Information Fusion, Volume 45

    Author(s): Giancarlo Fortino, Hassan Ghasemzadeh, Raffaele Gravina, Peter X. Liu, Carmen C.Y. Poon, Zhelong Wang







  • 81 Disorders of Breathing During Sleep
    25 juin 2018
    Publication date: 2019
    Source:Kendig's Disorders of the Respiratory Tract in Children

    Author(s): David Gozal, Leila Kheirandish-Gozal

    This chapter reviews pertinent mechanisms related to the maturation of respiratory control and upper airway function and then proceeds to describe several frequent conditions associated with sleep-disordered breathing, as well as unique diseases leading to breathing perturbations during sleep that provide insights on pathophysiology and clinical manifestations of these disorders.





  • Procedure 20 Mini-Open Biceps Tenodesis
    25 juin 2018
    Publication date: 2019
    Source:Operative Techniques: Shoulder and Elbow Surgery

    Author(s): Andrew S. Neviaser, Robert J. Neviaser







  • Procedure 37 Open and Arthroscopic Suprascapular Nerve Decompression
    25 juin 2018
    Publication date: 2019
    Source:Operative Techniques: Shoulder and Elbow Surgery

    Author(s): Aydin Budeyri, Sumant G. Krishnan

    Suprascapular nerve decompression is an important entity that is quite uncommon but may often be neglected. Physical examination, imaging techniques, and electromyographic studies are the keys to a successful diagnosis, treatment, and outcomes. With the help of contributions from the recent literature, current management and treatment techniques for suprascapular nerve compression are covered in this chapter.





  • Procedure 41 Nerve Transfers for Shoulder and Elbow Restoration After Upper Trunk Brachial Plexus Injuries
    25 juin 2018
    Publication date: 2019
    Source:Operative Techniques: Shoulder and Elbow Surgery

    Author(s): Christopher J. Dy, Scott W. Wolfe







  • Procedure 43 Suprascapular Nerve Neuropathy
    25 juin 2018
    Publication date: 2019
    Source:Operative Techniques: Shoulder and Elbow Surgery

    Author(s): Brandon J. Erickson, Anthony A. Romeo

    Although not a common cause of shoulder dysfunction in patients, entrapment of the suprascapular nerve can become a debilitating problem, specifically in the overhead athlete population. As this problem is somewhat rare, it can be difficult to diagnose on initial presentation and is often missed. The suprascapular nerve can be injured secondary to repetitive traction injury, trauma, and compression, often by cystic lesions. The nerve is specifically vulnerable to injury at two points along its course: the suprascapular notch and spinoglenoid notch. Entrapment of the suprascapular nerve typically occurs in patients between the ages of 20 and 50 years, is more common in men than women, and has a reported incidence of 1%–2% in the general population in patients who present with shoulder pain. There are several athletic populations that are at risk for suprascapular nerve entrapment, including swimmers, volleyball players, tennis players, and baseball players, with baseball pitchers and volleyball players at the highest risk for injury. Unless a large cystic lesion is seen compressing the suprascapular nerve on magnetic resonance imaging (MRI), nonoperative management is typically the initial treatment of choice. In patients who fail a course of nonoperative treatment, operative decompression can provide excellent results when performed well.





  • Index
    25 juin 2018
    Publication date: 2019
    Source:Operative Techniques: Shoulder and Elbow Surgery









  • Chapter 14 Disorders of Consciousness
    25 juin 2018
    Publication date: 2019
    Source:Rehabilitation After Traumatic Brain Injury

    Author(s): Sunil Kothari, Ekua Gilbert-Baffoe, Katherine A. O’Brien

    This chapter reviews issues central to the rehabilitation of persons with a disorder of consciousness (DoC). After a discussion of the nomenclature and taxonomy of DoC, the bulk of the chapter is focused on the assessment and treatment of these patients. An emphasis is placed on the issues and modalities that are directly relevant to clinicians practicing in this field. However, newer approaches and technologies are briefly introduced so that clinicians will be aware of them. There are also brief discussions of epidemiology, outcomes, ethical issues, and systems of care.





  • Chapter 17 Neuroprosthetics
    25 juin 2018
    Publication date: 2019
    Source:Rehabilitation After Traumatic Brain Injury

    Author(s): Sheital Bavishi, Joseph Rosenthal, Marcia Bockbrader

    A neuroprosthetic is any device that can enhance the input or output of a neural system. Although some neuroprosthetics, such as cochlear implants and visual prosthetics, have been around since the 1950s, they are just beginning to emerge as viable interventions in the field of brain injury. Neuroprosthetics encompass a variety of artificial devices or systems that can be used to enhance the motor, sensory, cognitive, visual, auditory, and communicative deficits that arise from acquired brain injuries. These include assistive technology, functional electrical stimulation, myoelectric prostheses, robotics, virtual reality gaming, and brain stimulation. Neuromodulation consists of extracranial stimulation devices such as transcranial direct current stimulation and transcranial magnetic stimulation or implanted devices such as brain-computer interfaces and deep brain stimulators. The objective of neuroprosthetics is to allow brain-injured people to participate in everyday life and enhance the quality of life.





  • Electrodiagnostic findings in postoperative C5 palsy after cervical laminectomy and fusion
    25 juin 2018
    Publication date: December 2018
    Source:Interdisciplinary Neurosurgery, Volume 14

    Author(s): Alexander Tucker, Agnes Wallbom, Marissa Darling, David Nguyen, Richard Everson, Sergei Terterov, Anne Nastasi, Jean-Philippe Langevin

    Proximal upper extremity weakness is a poorly understood complication of cervical spine surgery. The cause of this complication is unknown, although most patients recover completely over weeks to months with conservative treatment. We present two cases of postoperative, transient clinical C5 palsy after laminectomy and fusion as well as pre- and postoperative electrodiagnostic (EDX) examinations which demonstrate C6 nerve root involvement. EDX studies performed after surgery revealed active denervation of the deltoid and biceps muscles on the symptomatic side. In contrast, the ipsilateral rhomboid muscles appeared unaffected. We suggest that the current models of postoperative C5 palsy pathogenesis may be inadequate to explain our findings and propose an alternative theory of watershed ischemia distal to the origin of the dorsal scapular nerve as a contributing factor to the etiology of this surgical complication. EDX studies may be used to assist with diagnosis, confirm involved root levels, estimate prognosis, to follow recovery or to offer clues into the pathophysiology of the condition.

    Graphical abstract

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  • Armrests and back support reduced biomechanical loading in the neck and upper extremities during mobile phone use
    25 juin 2018
    Publication date: November 2018
    Source:Applied Ergonomics, Volume 73

    Author(s): Kartheek Reddy Syamala, Ravi Charan Ailneni, Jeong Ho Kim, Jaejin Hwang

    Mobile phone use is known to be associated with musculoskeletal pain in the neck and upper extremities because of related physical risk factors, including awkward postures. A chair that provides adequate support (armrests and back support) may reduce biomechanical loading in the neck and shoulder regions. Therefore, we conducted a repeated-measures laboratory study with 20 participants (23 ± 1.9 years; 10 males) to determine whether armrests and back support during mobile phone use reduced head/neck flexion, gravitational moment, and muscle activity in the neck and shoulder regions. The results showed that the chair support (armrests and back support) reduced head/neck flexion (p < 0.001), gravitational moment (p < 0.001), and muscle activity (p < 0.01) in the neck and shoulder regions significantly compared to no chair support. These results indicate that a chair with adequate support can be an effective intervention to reduce the biomechanical exposures and associated muscular pain in the neck and shoulders during mobile phone use.





  • Effects of early morning nap sleep on associative memory for neutral and emotional stimuli
    25 juin 2018
    Publication date: 1 November 2018
    Source:Brain Research, Volume 1698

    Author(s): Marie Roxanne Sopp, Tanja Michael, Axel Mecklinger

    Emotional events are preferentially retained in episodic memory. This effect is commonly attributed to enhanced consolidation and has been linked specifically to rapid eye movement (REM) sleep physiology. While several studies have demonstrated an enhancing effect of REM sleep on emotional item memory, it has not been thoroughly explored whether this effect extends to the retention of associative memory. Moreover, it is unclear how non-rapid eye movement (NREM) sleep contributes to these effects. The present study thus examined associative recognition of emotional and non-emotional material across an early morning nap (N = 23) and sustained wakefulness (N = 23). Nap group subjects demonstrated enhanced post-sleep associative memory performance, which was evident across both valence categories. Subsequent analyses revealed significant correlations between NREM spindle density and pre-sleep memory performance. Moreover, NREM spindle density was positively correlated with post-sleep neutral associative memory performance but not with post-sleep emotional associative memory. Accordingly, only neutral associative memory, but not emotional associative memory, was significantly correlated with spindle density after an additional night of sleep (+24 h). These results illustrate a temporally persistent relationship between spindle density and memory for neutral associations, whereas post-sleep emotional associative memory appears to be disengaged from NREM-sleep-dependent processes.





  • Optimal participation of low voltage renewable micro-grids in energy and spinning reserve markets under price uncertainties
    25 juin 2018
    Publication date: November 2018
    Source:International Journal of Electrical Power & Energy Systems, Volume 102

    Author(s): Pary Fazlalipour, Mehdi Ehsan, Behnam Mohammadi-Ivatloo

    Integrating independent dispatchable and non-dispatchable resources into a micro-grid platform enables the main power systems to benefit from the economic and environmental advantages of distributed generation while facilitating local, clean, and inexhaustible renewable energy production. Moreover, it makes the integrated components more visible and controllable for the whole power system. On the other hand, to properly handle multiple uncertainties inherent in the micro-grids, probabilistic energy management techniques are deployed. However, utilization of stochastic modeling and optimization tools for efficient, reliable, and cost-effective planning, operation, and control of micro-grids remains an open issue. In this paper, the optimal offering of a low voltage renewable micro-grid in the energy and reserve markets is investigated. The energy and reserve prices are assumed to be uncertain; therefore, lognormal probability density function is used to model energy and reserve price uncertainties, and the Latin Hypercube Sampling method is applied to generate appropriate prices. In addition, a bi-level stochastic programming approach is utilized to optimize the resultant large size MINLP model through the combination of AlphaECP and LindoGloabal solvers in GAMS. The value of stochastic solution is also evaluated to indicate the accuracy of the stochastic solutions.





  • How does the biomechanical exposure of the upper body in manual box handling differ from exposure in other tasks in the real industrial context?
    25 juin 2018
    Publication date: November 2018
    Source:International Journal of Industrial Ergonomics, Volume 68

    Author(s): Helen Cristina Nogueira, Francisco Locks, Dechristian França Barbieri, Ana Beatriz Oliveira

    The assessment of biomechanical exposure during handling tasks in relation to other activities that are performed in industrial settings can be crucial to understand the biomechanical demands of manual box handling for the upper limbs. This study aims to evaluate the representativeness of the handling task to the upper body in comparison with the other tasks in a real setting, compare the biomechanical exposure between tasks, and identify the differences in exposure during manual box handling from job exposure. Twelve workers had biomechanical exposure assessed through trapezius muscle activity and posture recordings (upper back and upper arms) during 4 h of a regular working day. Handling tasks demonstrated the highest biomechanical demand to the upper body, particularly for peak loads of the upper trapezius activation and upper back forward flexion postures. However, handling tasks were also associated with a high exposure variation. Interventions aiming to decrease loads in handling tasks can be relevant to decreasing peak loads and avoiding musculoskeletal disorders on the upper limbs. Relevance to industry Manual box handling is an occupational task commonly associated with musculoskeletal injury risk. Knowing the representativeness of manual box handling tasks in real work contexts can help practitioners to better understand the actual need for task-centered interventions.





  • The influence of job rotation and task order on muscle responses in females
    25 juin 2018
    Publication date: November 2018
    Source:International Journal of Industrial Ergonomics, Volume 68

    Author(s): Kristen D. Dickhout, Kathleen F. MacLean, Clark R. Dickerson

    Job rotation aims to reduce muscle fatigue by switching between functionally different tasks to theoretically lessen the risk of site-specific fatigue and work-related musculoskeletal disorders (WMSDs). The effectiveness of job rotation in mitigating the onset of muscle fatigue is partially known, but there is limited ergonomic data on female populations despite comparatively lower upper body strength and increased risk of WMSDs. Rotating between two functionally different tasks, continuing a single task, and varying task order were assessed in the present study for influence on muscle fatigue indicators in a female population. Participants performed a randomized set of four task combinations involving two unilateral, repetitive shoulder tasks (forward flexion and internal rotation). During these combinations, maximal voluntary force, mean power frequency, average EMG (aEMG) and ratings of perceived exertion (RPE) were recorded. Differences between task combinations and time were tested using a two-way repeated measures ANOVA. Indications of fatigue were limited in the results. Forward flexion (p = 0.004) and internal rotation (p = 0.002) maximum voluntary force declined in all task combinations while RPE increased (p < 0.0001); non-rotating task combinations had the greatest declines in force and increases in RPE. Results from EMG amplitude were less clear, and were muscle and task specific. While non-rotating task combinations had the greatest decrements in aEMG submaximal force, rotating task combinations often had similar decrements, creating limited statistical differences. Changes in aEMG were too small to distinguish an order effect. The EMG results suggest muscular demand overlap between the two tasks, despite being functionally different. The effectiveness of job rotation is partially dependent on selecting tasks that engage distinct muscle groups.





  • The interaction effect of working postures on muscle activity and subjective discomfort during static working postures and its correlation with OWAS
    25 juin 2018
    Publication date: November 2018
    Source:International Journal of Industrial Ergonomics, Volume 68

    Author(s): Tobias Hellig, Alexander Mertens, Christopher Brandl

    Methods assessing exposure to workload calculate risk scores of individual body segments which are added up to calculate an overall risk score for the whole body. However, these methods ignore interaction effects of body segments. This may lead to inaccurate assessment of risk scores of workload. The aim of the study was to examine interaction effects of shoulder flexion angle and back angle on rating of perceived exertion (RPE) and muscle activity, and to investigate the correlation between corresponding Ovako Working Posture Analysing System (OWAS) risk scores on the one hand and RPE and muscle activity on the other. The study revealed that there is a significant interaction effect of back angle and shoulder angle on muscle activity and RPE. Furthermore, OWAS seems to correlate only with back muscle activity. Thus, integration of interaction effects to ergonomic assessment methods seems to provide a higher accuracy of risk scores. Relevance to industry This article introduces the relevance of interaction effects of body segments to the assessment of workload. The study revealed that isolated assessment of working postures ignores interaction effects. A consideration of interaction effects leads to a higher accuracy of risk scores quantifying exposure to workload.





  • Surface electromyography for risk assessment in work activities designed using the “revised NIOSH lifting equation”
    25 juin 2018
    Publication date: November 2018
    Source:International Journal of Industrial Ergonomics, Volume 68

    Author(s): Alberto Ranavolo, Tiwana Varrecchia, Sergio Iavicoli, Agnese Marchesi, Martina Rinaldi, Mariano Serrao, Silvia Conforto, Mario Cesarelli, Francesco Draicchio

    The aims of this study were: to identify surface electromyography (sEMG)-based indices of trunk muscles acquired during the execution of lifting tasks designed using the revised NIOSH lifting equation and featuring a progressively increasing lifting index (LI); to study changes of these indices in relation to the LI; to evaluate the relationship between the identified indices and forces ( F L 5 S 1 ) and moments ( M L 5 S 1 ) at the L5-S1 joint. sEMG, kinematic and kinetic data of 20 male workers were recorded in three conditions. We computed the average rectified value (ARV), root mean square (RMS) and maximum value (Max) of twelve trunk muscles and the muscle co-activation. We also estimated F L 5 S 1 and M L 5 S 1 . One-way repeated-measures ANOVA and post-hoc analysis showed that sEMG-based indices values increased with LI increment of 1 (LI = l, 2 and 3). sEMG and kinetic parameters were linearly correlated. Findings suggest a promising use of wearable sEMG sensors in developing instrumental-based risk assessment tools in either the laboratory or workplace. In fact, some indices discriminate the investigated risk levels and correlate with the variables that generate the damage.

    Graphical abstract

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  • Failure of ventilation intra-operatively with NIM EMG endotracheal tube
    25 juin 2018
    Publication date: November 2018
    Source:Journal of Clinical Anesthesia, Volume 50

    Author(s): Chien-Hsun Chen, Cheng-Yu Chen, Yi-Jer Hsieh







  • Characterization of microstructural changes due to prolonged thermal exposure of directionally solidified Ni-base super alloy CM 247LC using ultrasonic
    25 juin 2018
    Publication date: November 2018
    Source:Ultrasonics, Volume 90

    Author(s): Amretendu Mukhopadhyay, Dibyendu Chatterjee, Chandan Mondal, Sony Punnose, K. Gopinath

    The high temperature strength of directionally solidified Ni-base super alloy CM 247LC strongly depends on the morphology, volume fraction, size and size distribution of γ′ precipitate (Ni3Al) in the FCC γ matrix. The microstructure of the alloy is engineered to achieve the right combination of these parameters that provides the required high temperature strength and creep resistance. The alloy contains high volume fraction of coherent γ′ precipitates having near cubic shape. High temperature exposure of gas turbine components made out of the alloy leads to coarsening of the γ′ precipitates and broadening of the γ matrix channel. This in turn, adversely affects the high temperature mechanical properties of the alloy. The present study endeavours to non-destructively characterize such detrimental changes in the microstructure that controls the mechanical properties and limits the life of components. The microstructural changes of the fully heat treated alloy exposed at 980 °C for different hours (100–1200) of thermal exposure have been characterized using ultrasonic methods. Changes in microstructural parameters due to different hours of thermal exposure have been correlated with changes in ultrasonic velocity, ultrasonic attenuation coefficient and second order acoustic nonlinearity parameter. It is observed that the change in attenuation is predominantly by absorption of the ultrasonic wave due to dislocation damping in the γ channels. Nonlinear ultrasonic parameter changes with thermal exposure predominantly due to the alteration of dislocation precipitate interaction. A dislocation precipitation interaction model for ultrasonic wave distortion has been used to explain the observed variation in nonlinear parameter. A microstructural parameter has been identified that varies in a similar way as ultrasonic attenuation and second order ultrasonic parameter. It is shown that variations in the acoustic non-linearity parameter follow the trend more closely with the identified microstructural parameter.





  • Influence of Zn substitution on the crystal structures and microwave dielectric properties of Li2(Mg1-xZnx)3TiO6 (0≤x≤0.2) ceramics
    25 juin 2018
    Publication date: 5 October 2018
    Source:Journal of Alloys and Compounds, Volume 764

    Author(s): C.H. Yang, H.L. Pan, Y.K. Yang, H.T. Wu

    A series of Zn-doped Li2(Mg1-xZnx)3TiO6 (x = 0, 0.05, 0.10, 0.15, 0.2) ceramics were formed via the conventional solid-state process. Influence of Zn2+ on the crystal structures, phase compositions, sintering characteristics and properties of Li2(Mg1-xZnx)3TiO6 (0 ≤ x ≤ 0.2) ceramics were systematically studied. XRD results showed that a single phase with the cubic rock-salt structure was formed for Li2(Mg1-xZnx)3TiO6 (0 ≤ x ≤ 0.15) and the second phase of Zn2TiO4 could be detected with a further increase of the Zn2+ contents. Some intrinsic parameters were calculated in order to investigate the correlations between these parameters of Mg/ZnO bonds and microwave dielectric properties. As the Zn2+ content increases, optimum ε r values exhibited an increasing trend, which could be explained by the variations of the polarizability and bond ionicity of Mg/ZnO bonds. The decrease of maximum Q·f values for Li2(Mg1-xZnx)3TiO6 (x = 0, 0.05, 0.10, 0.15, 0.2) ceramics could be predicted by the decrease of the packing fraction and lattice energy of Mg/ZnO bonds. τ ƒ values showed close relationship with the bond energy and thermal expansion coefficient of Mg/ZnO bonds. Excellent combined microwave dielectric properties with ε r  = 15.46 (at 10.9 GHz), Q·f = 125,453 GHz (at 8.6 GHz) and τ f  = −32.35 ppm/°C were obtained for Li2(Mg0.85Zn0.15)3TiO6 ceramic sintered at 1600 °C.

    Graphical abstract

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  • Simple fabrication method of an ultrasensitive gold micro-structured dry skin sensor for biopotential recording
    25 juin 2018
    Publication date: 5 October 2018
    Source:Microelectronic Engineering, Volume 197

    Author(s): Partha Sarati Das, Hyo Sang Yoon, Jiyoung Kim, Dae Heum Kim, Jae Yeong Park

    Fast advancement of dry biopotential electrode has driven to the reduction of using Ag/AgCl (wet electrode). There is a necessity for development of flexible and eco-friendly micro-structured (MSE) dry biopotential electrode utilizing biodegradable and non-toxic materials for a better life and sustainable future. It is very difficult to create micro-structure without using any solvents or high-end equipment. Here, a novel micro-structured electrode coated with Ti/Au film is fabricated using a sandpaper template and is proposed for biopotential signal monitoring applications. We used sandpaper, which is recyclable and biodegradable. The proposed MSE is a flexible, stretchable, and biocompatible dry micro-structured electrode. The sheet resistance of the proposed MSE is 2.5 Ω/sq. The area of MSE was only 4 cm × 4 cm (l × w), and the sweat of the epidermis layer of human skin could be utilized as the electrolyte for the flexible MSE during the electrocardiography (ECG) and electromyography (EMG) recording. The fabricated MSE was enough thin and flexible to be well attached onto the skin. The contact impedance of the flexible MSE was stable and suitable for long-term biopotential recording. The main advantage of the electrodes is simple fabrication, which can be used in wearable electrode systems to monitor human health. The results of the experiment show that the proposed electrode can operate in dry conditions when the subject is resting, and it shows fewer motion artifacts during movement.





  • Re-thinking floor mat design from an ergonomics perspective: Can a two-part mat system reduce biomechanical loads during normal mat handling tasks?
    25 juin 2018
    Publication date: October 2018
    Source:Applied Ergonomics, Volume 72

    Author(s): Xueke Wang, Steven Bigelow, Kelly E. Seagren, Alaina K. Preddie, Zimei Wang, Ardiyanto Ardiyanto, W. Gary Allread, Steven A. Lavender

    Floor mats are commonplace in commercial buildings, particularly in entry ways. These mats are routinely handled by delivery personnel as the mats are picked up for cleaning and clean mats are deployed. A new two-part mat design, which eliminates the need to move the rubber base during mat change operations, was hypothesized to reduce the physical demands on delivery personnel. Electromyographic data from back and shoulder muscles and spinal kinematics were obtained as 12 volunteers simulated mat selection, mat deployment, and mat pick-up tasks. Other factors considered in this study included mat size, pick-up method, and mat textile orientation during deployment. Results indicated that the two-part design reduced muscle activation levels across all tasks. Biomechanical benefits were also found when the mats were picked-up using a kick-fold as opposed to hand-fold method and when mats were deployed with the textile component rolled towards the inside of the roll.





  • Effects of standing on typing task performance and upper limb discomfort, vascular and muscular indicators
    25 juin 2018
    Publication date: October 2018
    Source:Applied Ergonomics, Volume 72

    Author(s): Larissa M. Fedorowich, Julie N. Côté

    Standing is a popular alternative to traditionally seated computer work. However, no studies have described how standing impacts both upper body muscular and vascular outcomes during a computer typing task. Twenty healthy adults completed two 90-min simulated work sessions, seated or standing. Upper limb discomfort, electromyography (EMG) from eight upper body muscles, typing performance and neck/shoulder and forearm blood flow were collected. Results showed significantly less upper body discomfort and higher typing speed during standing. Lower Trapezius EMG amplitude was higher during standing, but this postural difference decreased with time (interaction effect), and its variability was 68% higher during standing compared to sitting. There were no effects on blood flow. Results suggest that standing computer work may engage shoulder girdle stabilizers while reducing discomfort and improving performance. Studies are needed to identify how standing affects more complex computer tasks over longer work bouts in symptomatic workers.





  • Prognostic value of the blink reflex test in Bell’s palsy and Ramsay-Hunt syndrome
    25 juin 2018
    Publication date: October 2018
    Source:Auris Nasus Larynx, Volume 45, Issue 5

    Author(s): Young Min Hah, Sang Hoon Kim, Junyang Jung, Sung Su Kim, Jae Yong Byun, Moon Suh Park, Seung Geun Yeo

    Objective This study was designed to evaluate the prognostic value of the blink reflex (BR) test in patients with Bell’s palsy (BP) or Ramsay Hunt syndrome (RHS). Methods The House–Brackmann (HB) grade of patients diagnosed with BP and RHS was determined at first visit and 3 months later. Final HB grade III–VI was defined as an incomplete recovery. Factors evaluated as prognostic of poor recovery included electroneurography (ENoG) degeneration rate (DR)>90%, and absence of BR. Rates of complete and incomplete recovery were calculated and the associations between prognostic factors and recovery were determined. Results Of the 129 included patients, 98 (76%) had BP and 31 (24%) had RHS. Absence of BR and low mean ENoG value were significantly associated with incomplete recovery in both the BP and RHS groups (p<0.05 each). Initial HB grade V–VI was significantly associated with rate of incomplete recovery in patients with RHS (p<0.05 each). Severe residual palsy (final HB grade V–VI) in the absence of BR was significantly more frequent in patients with RHS than with BP (p<0.05). Conclusion BR test results were a good prognostic indicator in patients with BP and RHS, as were ENoG value. Absence of BR was more frequently associated with severe residual palsy in RHS than in BP.





  • Relation between globus pharyngeus and OSA in patients examined simultaneously by PSG and pH monitor: A cross sectional study
    25 juin 2018
    Publication date: October 2018
    Source:Auris Nasus Larynx, Volume 45, Issue 5

    Author(s): Ayako Fukui, Meiho Nakayama, Naoko Sakamoto, Sachie Arima, Shintaro Sato, Motohiko Suzuki, Shingo Murakami

    Objective This was a first cross-sectional single-center study to research the relation between globus pharyngeus, OSA and GERD. Since previous clinical studies have demonstrated a relationship between globus phayrngeus and GERD, however, no reported study on the relation between globus pharyngeus, sleep disorders including OSA, and GERD. Methods Seventeen patients underwent general and otorhinolaryngological examinations and responded to several questionnaires (ESS, PSQI, HADS, and Globus pharyngeus VAS score) at their first visit, and underwent a gastroesophageal test for 24-h pH monitoring and in-laboratory PSG one to two months later. Results No significant differences were seen in ESS, PSQI, or HADS scores between the groups. The acid exposure time was not significantly different among the groups. The percentage of esophageal reflux time was higher than the percentage of laryngopharyngeal reflux time through the total time as well as the supine period. This indicated that GERD occurred more frequently than laryngopharyngeal reflux. The entire results showed concurrent OSA in 10 cases (59%) and concurrent GERD in 7 cases (41%). The cases with OSA were treated by CPAP or oral appliance, and those treatments were effective for globus pharyngeus. Conclusion Although the relation between OSA and globus phayngeus is still controversial, these findings suggest that OSA may be a previously undetected cause of globus pharyngeus. By improving OSA, it may offer an additional option of treatment for those globus pharyngeus cases combined with OSA.





  • Greater rewards in videogames lead to more presence, enjoyment and effort
    25 juin 2018
    Publication date: October 2018
    Source:Computers in Human Behavior, Volume 87

    Author(s): Daniel Johnson, Madison Klarkowski, Kellie Vella, Cody Phillips, Mitchell McEwan, Christopher N. Watling

    There is currently limited understanding of whether and how different amounts and diversity of virtual rewards impact on the player experience. A repeated-measures experiment was undertaken in which participants (N = 59) were compared on subjective measures (competence, presence-immersion, tension, effort and enjoyment), as well as psychophysiological measures (electrodermal activity and heart-beat rate), during the play of a videogame with three levels of video game reward (high, medium, low). Effort, enjoyment and presence-immersion significantly varied across conditions such that they were greater when all rewards were present compared to one or both of the other conditions. Heart-beat rate was found to vary across conditions consistent with the explanation that greater rewards lead to greater arousal. Our study suggest a number of advantages to greater amount and diversity of virtual rewards in the context of a casual videogame, with potential application to the design of new gamification systems.





  • Improving the SoilPlusVeg model to evaluate rhizoremediation and PCB fate in contaminated soils
    25 juin 2018
    Publication date: October 2018
    Source:Environmental Pollution, Volume 241

    Author(s): Elisa Terzaghi, Melissa Morselli, Elisabetta Zanardini, Cristiana Morosini, Giuseppe Raspa, Antonio Di Guardo

    Tools to predict environmental fate processes during remediation of persistent organic pollutants (POPs) in soil are desperately needed since they can elucidate the overall behavior of the chemical and help to improve the remediation process. A dynamic multimedia fate model (SoilPlusVeg) was further developed and improved to account for rhizoremediation processes. The resulting model was used to predict Polychlorinated Biphenyl (PCB) fate in a highly contaminated agricultural field (1089 ng/g d.w.) treated with tall fescue (Festuca arundinacea), a promising plant species for the remediation of contaminated soils. The model simulations allowed to calculate the rhizoremediation time (about 90 years), given the available rhizoremediation half-lives and the levels and fingerprints of the PCB congeners, to reach the legal threshold, to show the relevance of the loss processes from soil (in order of importance: degradation, infiltration, volatilization, etc.) and their dependence on meteorological and environmental dynamics (temperature, rainfall, DOC concentrations). The simulations showed that the effective persistence of PCBs in soil is deeply influenced by the seasonal variability. The model also allowed to evaluate the role of DOC as a possible enhancer of PCB degradation as a microorganism “spoon feeder” of PCBs in the soil solution. Additionally, we preliminary predicted how the contribution of PCB metabolites could modify the PCB fingerprint and their final total concentrations. This shows that the SoilPlusVeg model could be used in selecting the best choices for a sustainable rhizoremediation of a POP contaminated site.

    Graphical abstract

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    Teaser

    An environmental fate model to simulate the rhizoremediation processes of PCBs in soil was developed and tested.



  • “Dior, J’adore”: The role of contextual information of luxury on emotional responses to perfumes
    25 juin 2018
    Publication date: October 2018
    Source:Food Quality and Preference, Volume 69

    Author(s): Tiffany Baer, Géraldine Coppin, Christelle Porcherot, Isabelle Cayeux, David Sander, Sylvain Delplanque

    Luxury conveys values of quality and rarity and holds a particular emotional meaning. Yet, studies conducted on the impact of contextual information of luxury on emotional responses to products remain scarce. In this study, we tested whether contextual information, in particular evoking luxury, could influence emotional responses to perfumes, which are known to be powerful elicitors of emotion. More specifically, we measured the subjective, physiological, and expressive components of participants’ emotional responses. We conducted an experiment in which participants had to smell and assess perfumed pens as well as blank pens (i.e., without perfume) presented either in a luxurious context (i.e., name, brand and bottle), a non-luxurious one, or no information. Results indicated that participants tended to rate perfumes as more pleasant and rated them as more familiar when presented in a luxurious context than in a non-luxurious one or without context, and the blank pen as more irritating in a non-luxurious context than in a luxurious one. However, we did not find evidence of a significant contextual information effect on expressive or physiological indicators. Our findings suggest that contextual information of luxury can moderately influence the subjective component of participants’ emotional responses, while no evidence for such effect was found with respect to the physiological and expressive components.





  • An automatic, adaptive, information-based algorithm for the extraction of the sEMG envelope
    25 juin 2018
    Publication date: October 2018
    Source:Journal of Electromyography and Kinesiology, Volume 42

    Author(s): Simone Ranaldi, Cristiano De Marchis, Silvia Conforto

    Surface ElectroMyography (sEMG) is widely used as a non-invasive tool for the assessment of motor control strategies. However, the standardization of the methods used for the estimation of sEMG amplitude is a problem yet to be solved; in most cases, sEMG amplitude is estimated through the extraction of the envelope of the signal via different low-pass filtering procedures with fixed cut-off frequencies chosen by the experimenter. In this work, we have shown how it is not possible to find the optimal choice of the cut-off frequency without any a priori knowledge on the signal; considering this, we have proposed an updated version of an iterative adaptive algorithm already present in literature, aiming to completely automatize the sEMG amplitude estimation. We have compared our algorithm to most of the typical solutions (fixed window filters and the previous version of the adaptive algorithm) for the extraction of the sEMG envelope, showing how the proposed adaptive procedure significantly improves the quality of the estimation, with a lower fraction of variance unexplained by the extracted envelope for different simulated modulating waveforms (p < 0.005). The definition of an entropy-based convergence criterion has allowed for a complete automatization of the process. We infer that this algorithm can ensure repeatability of the estimation of the sEMG amplitude, due to its independence from the experimental choices, so allowing for a quantitative interpretation in a clinical environment.





 

Mis à jour le 03 avril 2013