bluuebunny/crossref_metadata_2025 huggingface dataset:
Reproductive phenologies of phyllostomid bat populations and ensembles from lowland Amazonia
Authors: Willig Michael R , Presley Steven J
Published: March 2023

Natural selection should favor individuals that synchronize energy-demanding aspects of reproductive activity with periods of high resource abundance and predictability, leading to seasonal patterns of reproduction at the population level. Nonetheless, few studies—especially those on bats in the Neotropics—have used rigorous quantitative criteria to distinguish among phenological patterns for different populations from the same habitat or for the same species in different habitats. To explore such issues, we quantified annual patterns of reproduction in male and in female bats from lowland Amazonia (environs of Iquitos, Peru), and did so at the level of populations and ensembles. Five species exhibited unimodal patterns including Artibeus obscurus, A. planirostris, Carollia benkeithi, Phyllostomus hastatus, and Rhinophylla pumilio. Two species (A. lituratus and Glossophaga soricina) evinced bimodal patterns with reproductive peaks separated by patterns of inactivity, whereas four species (C. brevicauda, C. perspicillata, Sturnira lilium, and S. tildae) evinced a bimodal pattern in which peaks in activity occur in tandem, with the first peak generally markedly higher than the second peak. Frugivore, gleaning animalivore, and nectarivore ensembles exhibited bimodal, unimodal, and bimodal reproductive phenologies, respectively. Nonetheless, interannual variation in phenology (i.e., the monthly timing of peaks within a season rather than the number of peaks per year) characterized four (A. obscurus, C. brevicauda, C. perspicillata, and S. lilium) of the eight species and each of the three ensembles (frugivores, gleaning animalivores, and nectarivores) with adequate sampling. Regardless of interspecific variation in strategies, the phenology of reproduction enhances the likelihood that parturition and recruitment of young into the population occurs during the wet season, the period of likely highest resource abundance. Based on a comparison of our results with those from other well-studied bat populations, four species did not exhibit geographic variation in reproductive phenologies (A. obscurus, G. soricina, C. brevicauda, and R. pumilio), whereas three species evinced such geographic variation (A. lituratus, A. planirostris, and C. perspicillata). Climate change will likely alter the seasons and extents of propitious times for reproductive activities, as well as the reliability of proximate cues for initiating reproduction, compromising current reproductive strategies and leading to altered phenological patterns of reproduction or reproductive success, possibly resulting in local extinction of some species.
Racial bias in jury selection
Authors: Salahub Chris
Published: March 2023

In criminal justice, the controversial peremptory challenge allows lawyers to dismiss potential jury members without giving a reason. Chris Salahub gathers data to paint a picture of racial bias in jury selection
Bodily-Material Culture Techniques in the Spaces of the Devotional Revolution
Authors: Godson Lisa
Published: March 2023

This essay addresses how new procedural knowledge was promoted during the devotional revolution in nineteenth-century Ireland, particularly in relation to bodily-material culture techniques. It argues that a more orthopraxic physical disposition was a significant aspect of the experience and practice of Catholicism, and suggests ways of thinking about that in relation to religious imagination and space. In this, it sees bodies as connected to artefacts through material practices. The bodily-material culture techniques under discussion include gesture, ways of interacting with objects and spaces, and in general the embedding of new forms of material knowledge and body schema. In this, this essay re-examines the relationship between religious and secular space during this period. On the one hand, at this time the intense construction and prominent siting of thousands of religious buildings including churches, denominational institutions and entire urban quarters suggest that sacred and secular spaces were highly defined and circumscribed. However, a focus on bodies and objects also suggests the idea of immanence, and a more fluid inter-relationship between sacred and profane space than might be generally considered. The contribution draws largely on regulatory and instructive literature including catechisms and popular devotional tracts, personal testimony and specific liturgical and devotional objects and spaces.
Long-Term or Chronic Risk Factors
Authors: Galynker Igor
Published: March 2023

This chapter describes various long-term (chronic) risk factors for suicide and examines their empirical base. The chapter discusses demographic risk factors, such as gender and age, as well as psychological risk factors, including impulsivity, hopelessness, perfectionism, pain insensitivity, and attachment style. Well-established historical factors, such as history of mental illness, past suicide attempts, and childhood trauma, are also outlined. Last, the chapter investigates the link between suicide and sociocultural risk factors, including cultural attitudes, immigration-related experiences, moral and religious objections, and suicide clusters. The chapter illustrates the role of long-term risk factors in the NCM through three case examples and a test case.
Continuous Positive Airway Pressure and Positive End-Expiratory Pressure
Authors: Selvamani Breethaa Janani , Sharma Archit
Published: March 2023

Aerated lung volume is reduced during anesthesia because of loss of muscle tone. This causes atelectasis, which impairs gas exchange in both intubated patients and patients who have been extubated after surgery. Atelectasis may remain for several days in the postoperative period, giving more time for potential negative consequences than during the anesthesia itself. Preventing fall in end-expiratory lung volume during the emergence from anesthesia by applying positive end-expiratory pressure (PEEP)/continuous positive airway pressure (CPAP) reduces early postoperative atelectasis and improves the ventilation/perfusion ratio. Both CPAP and PEEP reduce the work of breathing and improve oxygenation by increasing functional residual capacity. This chapter discusses the different physiologic effects of applying these maneuvers.
Hyperbaric Medicine
Authors: Covington Derek Brady , Giordano Christopher
Published: March 2023

Hyperbaric oxygen therapy (HBOT) is the medical use of oxygen at higher than atmospheric pressures. HBOT occurs in monoplace or multiplace chambers. Along with the hyperoxygenation that occurs when increased pressure dissolves additional oxygen into the plasma, HBOT induces several additional therapies via alternative mechanisms of action. For instance, HBOT induces vasoconstriction, angiogenesis, fibroblast proliferation, and antibiotic synergy. The only contraindication to HBOT is an untreated pneumothorax because increased pressurization could exacerbate a pneumothorax as well as evolve into a tension pneumothorax. The most common complication secondary to HBOT is middle ear barotrauma or the inability to equalize the middle ear space with resultant otalgia. Although an oxygen-induced seizure may manifest secondary to central nervous system toxicity, these are exceedingly rare and often benign. When treating a mechanically ventilated patient, it is imperative to consider the volume of the endotracheal cuff. In accordance with Boyle’s law, as pressure increases, volume decreases. Thus, on pressurization of the chamber, gas must be added to the endotracheal tube cuff to maintain an adequate seal on the tracheal mucosa. On depressurization, gas must be removed from the endotracheal tube cuff to prevent excessive expansion and damage to the trachea. The use of a manometer while adding or removing gas from the endotracheal tube facilitates the maintenance of a proper cuff volume and subsequent seal. If critically injured patients require HBOT, it is imperative that ventilators, syringe pumps, and all other medical devices are safe for hyperbaric oxygen.
Electroencephalograms
Authors: Abdallah Rany T. , Coleman Gabriel M.
Published: March 2023

An electroencephalogram (EEG) is a device used to measure electrical activity in the brain by placing several pairs of electrodes at specific positions over the scalp. When an axon excites a neuron, a small, varying electrical field is generated that is picked up by the nearest electrode. Each pair of electrodes receives activity from different populations of neurons, which are transferred to a medium in a readable pattern. Distinct cortical areas will display similar electrical activity, which can be used to isolate and observe specific activity. The EEG has multiple uses in clinical practice, such as for determination of insomnia, hypothermia, hypercapnia, and brain death. EEG is also used in anesthesia monitoring. It is affected differently by different anesthetics.
Peripheral and Autonomic Nerve Blocks
Authors: Flaherty James , Jimenez-Ruiz Federico
Published: March 2023

Peripheral and autonomic nerve blocks involve the targeted injection of local anesthetics to reduce neuronal signal transmission. This chapter aims to provide an introduction to high-yield, American Board of Anesthesiology keyword–based topics related to their performance. A brief review of indications and contraindications for peripheral and autonomic nerve blocks is presented first. The chapter then provides a comparison of available techniques for nerve localization, with a focus on ultrasound guidance. An evidence-based review of complications from peripheral nerve blocks (nerve injury, bleeding, infection, and toxicity) is then provided. Finally, evidence supporting the provision of continuous, catheter-based, peripheral nerve blocks is presented.
Extremity Nerve Blocks
Authors: Flaherty James , Jimenez-Ruiz Federico
Published: March 2023

Peripheral nerves carry sensory, motor, and autonomic signals to and from the central nervous system. Advances in the study of functional anatomy and the application of ultrasound guidance have contributed significantly to the development of precise and novel peripheral nerve blocks. Regional anesthesia can be used as an alternative to general anesthesia or as a highly effective way to provide pain control and decrease opioid consumption. This chapter compiles high-yield facts and commonly tested material related to upper and lower extremity blocks. It is not intended to be a thorough presentation of all relevant information pertaining to the clinical application of regional anesthesia.
General Concepts in Pharmacology
Authors: Kapp Daniel Gonzalez
Published: March 2023

Pharmacology is the basic science of drug discovery, drug composition, pharmacokinetics, pharmacodynamics, and toxicology. A drug’s underlying pharmacology is fundamental to its potential therapeutic benefits and risks when used in clinical practice. Key chemistry-related concepts within pharmacology that describe a drug’s properties include pH, pKa, and protein binding. Perioperative assessment should include evaluation of chemistry-related factors affecting the transportation and distribution of drugs across body compartments. Patient-specific conditions to evaluate include those affecting blood pH (e.g., hyperventilation), plasma protein binding (e.g., low albumin due to malnutrition), and the pH of local environments (e.g., low pH in tissue due to infection).
Addiction
Authors: Shah Anuj A. , Zaky Christine S.
Published: March 2023

Addiction is a chronic physiological need for a habit-forming substance despite the harmful consequences. The drug addiction cycle includes three stages: preoccupation, withdrawal, and intoxication. In 2016, alcohol dependence was shown to be the most prevalent substance use disorder globally, while cannabis and opioid use disorders were found to be the most common drug use disorders. The pathophysiology of drug addiction involves changes in brain circuitry and critical neurotransmitters such as dopamine. The first steps in diagnosing a substance use disorder require acknowledgment of the disorder and the seeking of treatment along with assessment by an addiction specialist. Treatment of a specific drug addiction is dependent on the presence of acute intoxication, withdrawal, and/or abstinence. Acutely, alcohol intoxication is managed by long-acting benzodiazepines, while acute opioid intoxication is managed with naloxone. Pharmacological treatments have shown to be the most effective when combined with group meetings, psychological support, and physician advice. In all cases, early intervention has proven to be the most beneficial.
Nonsteroidal Anti-inflammatory Drugs (NSAIDs)
Authors: McGinty Lauren
Published: March 2023

The nonsteroidal anti-inflammatory drugs (NSAIDs) are widely used as prescription and over-the-counter medications to treat pain, inflammation, and fever associated with a variety of medical conditions. This chapter reviews the indications, mechanisms of action, therapeutic effects, adverse effect profiles, and special precautions associated with these different agents. It also provides information on the physiologic and the pathophysiologic roles of cyclooxygenase (COX) and prostaglandins and discusses the impact of COX selectivity. Finally, this chapter addresses key drug interactions and the available routes of administration for the different NSAIDs and highlights unique advantages and disadvantages of the agents in this medication class.
Antiemetics
Authors: Eapen Jeffery James , Bang Jason
Published: March 2023

Antiemetics are classes of medications that are cornerstones of a complete anesthetic care model. Postoperative nausea and vomiting has 20%–30% occurrence overall and is rated by many patients as more concerning than postoperative pain. This chapter focuses on the varying categories of antiemetics, their mechanisms of action, and common side effects. 5-Hydroxytryptamine (5-HT3), dopamine 2 receptor, histamine 1 receptor, and neurokinin 1 receptor antagonists are discussed as options for the management of nausea and vomiting. These medications exert their effects in areas that stimulate the vomiting center of the central nervous system, such as the area postrema and nucleus of the tractus solitarius. Notable side effects to pay particular attention to include QT prolongation with ondansetron and droperidol. Miscellaneous medications, such as propofol, can be used as rescue therapy for postoperative nausea and vomiting (PONV) refractory to conventional methods of treatment.
Chronic Opioid Dependence and Therapy
Authors: Parker Nicholas M.
Published: March 2023

Opioid use disorder (OUD) is highly prevalent, and its treatment presents several challenges to providing adequate but safe analgesia during and after surgery. Three medications are used to treat OUD: naltrexone, buprenorphine, and methadone. Each has distinct pharmacological properties and implications for anesthesia, as well as unique and complex legal restrictions on their use. The anesthesiologist must have a detailed understanding of OUD and these three medications to safely and legally provide analgesia without undue risk of overdose or relapse. Widespread naloxone prescribing and use of prescription drug monitoring systems (PDMPs) are other strategies to improve the safety of opioids for all patients.
Sympathetic Nervous System
Authors: George Shelley
Published: March 2023

The sympathetic nervous system combines with the parasympathetic system to form the autonomic nervous system, and together they help control bodily functions that are unconsciously directed. The sympathetic nervous system (SNS) extends throughout the whole body and allows the body to prepare for physical activity necessary in situations where the body needs to be on high alert. Although it has an afferent element, it is mostly known for its efferent component. The sympathetic fibers of the system are what contribute to the fight-or-flight response and forms from the thoracolumbar (T1-L3) segments of the spinal cord, whereas the parasympathetic fibers form from the cervicosacral portion of the spinal cord. The SNS employs an intricate system of nerve fibers, neurotransmitters, and receptors to achieve desired organ function.
Intracranial Aneurysms and Arteriovenous Malformation
Authors: Alkhalili Kenan , Nasr Ned F.
Published: March 2023

Intracranial vascular lesions are relatively common abnormalities that may require elective or emergent intervention. Advances in neuroimaging has led to an increase in the discovery of patients harboring incidental cerebral aneurysms. The overall prevalence of unruptured intracranial aneurysms (UIAs) is estimated to be 3%. The most feared complication is subarachnoid hemorrhage (SAH) from aneurysm rupture, which poses a worldwide health burden with high fatality and permanent disability rates. Arteriovenous malformations (AVMs) represent a different entity of vascular anomalies, more predominant in younger population. The arteries are directly connected to venous drainage, bypassing the capillary system and resulting in a high-flow, low-resistance anomaly. Brain AVMs are of special concern because of the inherent high risk of bleeding of the abnormal blood vessels, which can cause neurological damage. Anesthetic management of patients with complicated aneurysms/AVMs is challenging because of the emergency nature of the presentation, complex pathology, and varied intracranial and systemic manifestations. This chapter discusses the epidemiology, pathophysiology, management, and anesthesia considerations in unruptured and ruptured intracranial aneurysms and AVMs.
Interventional Neuroradiology
Authors: Alkhalili Kenan , Nasr Ned F.
Published: March 2023

Interventional neuroradiology (INR) is a rapidly evolving field with an expanding variety of indications and techniques. It encompasses the diagnosis and treatment of many neurovascular and spine conditions, including but not limited to cerebral aneurysm, arteriovenous malformations, cerebral vasospasm, and stroke management. To facilitate the close teamwork required between interventionists and anesthesiologists necessary for the successful outcome, it is important to have full understanding of cerebral protection strategies and the potential pitfalls of each procedure. Under normal circumstances, anesthesia goals revolve around maintaining patient immobility, avoiding hemodynamic alterations, and ensuring rapid recovery to facilitate postprocedure neurological evaluation. Interventional radiology suites pose challenges in anesthetic care due to their “off-site” location, remote from the main operating room area, which necessitates special preparations.
Pituitary Adenomas
Authors: Mori Benjamin B. G. , Nasr Ned F.
Published: March 2023

Pituitary adenomas are benign lesions commonly encountered in clinical practice. Functioning adenomas often result in symptoms related to hormone excess, whereas nonfunctioning adenomas often present later with symptoms secondary to mass effect of the tumor. Diagnosis is done by way of laboratory testing and magnetic resonance imaging (MRI). Transsphenoidal pituitary resection (TPR) is the mainstay of treatment for pituitary adenomas and poses unique challenges as it involves the principles and practices of both endocrine and neurosurgical management. Airway management may be difficult in patients with acromegaly or Cushing disease. The anesthetic management for pituitary surgery requires comprehensive preoperative assessment of hormonal function and airway anatomy. Intraoperative management revolves around facilitating surgical exposure while providing hemodynamic stability and allowing for rapid emergence. Postoperative disorders of sodium balance and pituitary hormone deficiency are common after pituitary surgery.
Postoperative Visual Loss
Authors: Teixeira Camila , Minear Steven
Published: March 2023

Postoperative visual loss (POVL) is an uncommon event that has a deep impact on the quality of life of patients undergoing surgical procedures, especially spine surgeries. Many causes have been addressed regarding POVL, although ischemic optic neuropathy (ION) is the most frequently described. Visual loss occurring after nonocular surgery with general anesthesia typically results from anterior ischemic optic neuropathy (AION), posterior ischemic optic neuropathy (PION), central retinal artery occlusion (CRAO), or cortical blindness. Current research and expert opinion indicate that there is a correlation with prolonged surgical times and intraoperative substantial blood loss. The American Society of Anesthesiologists developed a practice advisory for the prevention of this complication. Anesthetic techniques are designed to avoid hemodilution, hypotension, and, when possible, staging prolonged procedures. Risk factors should be assessed in the preoperative assessment, and it is recommended to inform patients at high risk for this complication.
Hypothermia
Authors: Bang Jarrod , Sharma Archit
Published: March 2023

A complication attributed to typical mild intraoperative hypothermia is prolonged duration of postanesthetic recovery. Temperature management is an important aspect of providing care for a patient in an operating room. Hypothermia is caused by heat loss, a decrease in heat production, or inhibition of the body’s innate thermoregulatory mechanisms. All three of these mechanisms can occur during general or regional anesthesia, resulting in the common occurrence of hypothermia during surgery. Perioperative hypothermia may prolong recovery by augmenting anesthetic potency, delaying drug metabolism, producing hemodynamic instability, or depressing cognitive function. This chapter discusses the different causes of perioperative hypothermia and their effects on a patient’s disease state and morbidity.
Arterial Blood Gas Interpretation
Authors: Maben Sarah
Published: March 2023

The arterial blood gas (ABG) provides information about a patient’s pH, oxygenation, and ventilation and can indicate whether an acid-base disorder is primarily metabolic, respiratory, or mixed. The four basic categories of acid-base disorders are respiratory acidosis, respiratory alkalosis, metabolic acidosis, and metabolic alkalosis. The anion gap (AG) is calculated from the difference in cations and anions and can be used to tailor a differential diagnosis based on the mechanism of the acid-base disorder. The lungs and kidneys affect acid-base disorders by compensatory mechanisms that must be considered during ABG interpretation. Additionally, the patient’s clinical history is important for further narrowing a differential diagnosis. Taken together, ABG interpretation can provide a concise differential diagnosis for a particular acid-base disorder.
Management of Patients With Respiratory Disease
Authors: Roberman Dmitry , Suero Felipe F.
Published: March 2023

Patients with respiratory diseases are at increased risk of perioperative complications. There is increasing awareness of the importance of postoperative pulmonary complications in contributing to morbidity, mortality, and increased hospital length of stay. Because of the prevalence of smoking and obesity, many patients may be at increased risk of developing postoperative pulmonary dysfunction. Patients with known disease should have their pulmonary function optimized preoperatively, with careful consideration given to the choice of general versus regional anesthesia. A choice of invasive and noninvasive monitors should be considered when providing anesthesia to patients with respiratory compromise. Be mindful that an invasive monitor such as an arterial line can provide a wealth of information during operation.
Preoperative Evaluation and Preparation of the Patient With Pulmonary Disease
Authors: Brown Anna-Kaye , Hauck Ellen
Published: March 2023

Surgical candidates with pulmonary disease are at increased risk of postoperative pulmonary complications. This chapter discusses important components of the preoperative evaluation and preparation for patients with pulmonary hypertension, obstructive airway disease, restrictive lung disease, and obstructive sleep apnea. The preoperative evaluation indicates the stability of cardiopulmonary conditions, identifies risk factors that necessitate additional workup, and estimates the perioperative risk for surgery. After preoperative evaluation, including use of pulmonary risk indexes to estimate the risk of postoperative pulmonary complications, patients can then receive appropriate preoperative preparation and optimization. Preoperative optimization strategies such as respiratory and pharmacologic therapies are addressed. Additionally, smoking cessation techniques and the benefits of quitting prior to surgery are discussed. Understanding the preoperative evaluation and preparation for patients with respiratory disease may reduce the risk of postoperative pulmonary complications.
Mode of Ventilation
Authors: Kapisoda Katarina , Crimi Ettore
Published: March 2023

Mechanical ventilation provides an artificial lung support that completely or partially supports the work carried by respiratory muscles. It is indicated in patients with inadequate respiratory drive, hypoxia, and failure to maintain adequate ventilation. Delivery of air into the lung under positive pressure via an artificial airway (endotracheal tube/tracheostomy tube) is referred to as invasive ventilation. Noninvasive ventilation uses a different interface (mask) and provides support without invasive artificial airway. The mode of mechanical ventilation defines the relationship between the type of breath (spontaneous, assisted, or mandatory) and a group of control variables (volume, pressure) and phase variables (trigger, limit, cycle) that regulate the pattern of breath delivery. Modes of ventilation include assist control, SIMV (synchronized intermittent mandatory ventilation), pressure support, pressure controlled and inverse ratio, APRV (airway pressure release ventilation), and high-frequency ventilation.
Management of Bronchospasm
Authors: Eapen Jeffery James , Bang Jason
Published: March 2023

Bronchospasm is a respiratory complication encountered with anesthesia practice; this chapter provides a review of the condition in terms of pathophysiology and its management in the perioperative period. Bronchospasm is a manifestation of a complication from reactive airway disease (asthma), chronic obstructive pulmonary disease (COPD), anaphylaxis, release of vasoactive substances, or interventions by an anesthesiologist. It is caused by increased activity of smooth muscles surrounding the bronchioles, resulting in airflow obstruction and impacting primarily the expiratory phase of the respiratory cycle. Diagnosis is confirmed by physical examinations revealing end-expiratory wheezes and increased peak airway pressures during mechanical ventilation. Management includes administering 100% oxygen, use of β2-agonists such as albuterol, increasing the inspired concentration of bronchodilating inhaled anesthetics, and using bronchodilating intravenous agents such as ketamine.
Echo Heart Anatomy
Authors: Gibson Christina , McConnell Matthew
Published: March 2023

Echocardiographic Heart Anatomy describes the 11 basic views utilized in the basic perioperative echocardiographic examination as well as the structures visualized in real-time diagnoses. The 11 views are seen in the midesophageal, transgastric, and upper esophageal portions of the gastrointestinal tract. Perioperative echocardiography is a useful tool and a relatively safe procedure, with very low morbidity and mortality. The primary goal of the basic echocardiographic examination is intraoperative monitoring, which aids in diagnosing hemodynamic instability in surgical patients. Such diagnoses include, but are not limited to, intravascular volume status, left ventricular dysfunction, right ventricular dysfunction, valvulopathies, cardiac tamponade, pulmonary emboli, and aortic dissection.
Subacute Bacterial Endocarditis Prophylaxis
Authors: Burger Melissa Anne , Jones Todd Everett
Published: March 2023

The American College of Cardiology and American Heart Association (ACC/AHA) guidelines for subacute bacterial endocarditis (SBE) prophylaxis now recommend SBE prophylaxis in only the high-risk subset of patients with prosthetic valves, congenital heart disease, or a cardiac transplant. SBE prophylaxis should be given for procedures involving manipulation of gingival tissues, the periapical region of teeth, perforation of the oral mucosa (including routine dental cleanings), or invasive respiratory tract procedures, but it is no longer recommended for genitourinary or gastrointestinal tract procedures. Parturients in select high-risk categories may benefit from antibiotics 30 minutes prior to vaginal delivery. Perioperative antibiotic selection should cover organisms most likely to cause SBE, notably Streptococcus viridans, and is based on the patient’s ability to tolerate oral medication and any penicillin allergy.
Myocardial Preservation During Cardiac Surgery
Authors: Trusheim Jay , Pappas Marisa
Published: March 2023

During cardiopulmonary bypass, there are several mechanisms utilized to protect the myocardium. These include the use of a cardioplegia solution, systemic and myocardial cooling, and decompression of the heart. Cardioplegia can be delivered either antegrade via the aortic root or retrograde via the coronary sinus in order to silence the electrical activity of the heart. Cooling can be accomplished either directly by ice, via the cardiopulmonary bypass machine, or by underbody coolers. Decompression is achieved with adequate venous drainage through the venous cannula allowing for decreased wall tension and thus decreased oxygen demand. With adequate myocardial protection, it is hoped the patient can be separated from bypass without new or worsening ventricular wall dysfunction.
Intra-Aortic Balloon Pumps
Authors: Barrack Frank , Noorda Bryan
Published: March 2023

The intra-aortic balloon pump (IABP) is the most common and readily available form of mechanical support for a failing heart. IABPs decrease myocardial oxygen consumption while increasing the oxygen supply to the myocardium, improving the oxygen supply/demand balance by a mechanism called counterpulsation. The IABP synchronizes with the heartbeat to inflate during diastole and deflate during systole. Increased diastolic pressure improves coronary perfusion, and systolic unloading decreases the oxygen consumption of the left ventricle. General indications for IABP placement are based on the beneficial physiological effects of the device. Complications arise from the process of placing the device or vascular injury associated with the prolonged use of IABPs.
Aortic Aneurysms
Authors: Bang Jarrod , Arora Lovkesh L.
Published: March 2023

Aortic aneurysms have a relatively high incidence in the general population, and the incidence increases with increasing age. The vast majority of aneurysms present asymptomatically, diagnosed incidentally or through regular screening, although some present emergently in cases of rupture. The location and extent of the aortic aneurysm, and associated disease, greatly affect surgical intervention and therefore anesthetic management. The anesthetic management of aortic aneurysm repair varies considerably depending on location and extent of the aneurysm. Open repair versus endovascular repair have important differences in anesthetic approach. Intimate knowledge of aortic cross clamping and unclamping physiologic responses, vasoactive medications, spinal cord perfusion, blood product administration, and intraprocedural communication are of utmost importance.
Morbid Obesity/Anesthesia for Bariatric Surgery
Authors: Roth Vincent , Giordano Christopher
Published: March 2023

Obesity is a global epidemic that requires special anesthetic considerations. The restrictive pulmonary pathophysiology of obesity increases sensitivity to apnea, while underlying cardiovascular comorbidities may put obese patients at greater risk of hemodynamic instability during anesthesia. Changes in airway anatomy can lead to obstructive sleep apnea (OSA) and other disordered breathing patterns that further exacerbate these risks. To minimize anesthetic risk, careful preoperative assessment must be done, including administration of the STOP-BANG questionnaire to screen for OSA, a 12-lead electrocardiogram, smoking cessation, and initiation of appropriate thromboprophylaxis. Intraoperatively, special attention must be paid to patient positioning, with the head and thorax ideally in the ramped position and the body in reverse Trendelenburg. This should facilitate successful intubation and minimize the effects of body habitus on respiratory function. Choice of drugs should be carefully considered, giving preference to drugs that are less lipophilic and more predictably metabolized whenever possible. Postoperatively, respiratory support and pain control must be properly attended to with use of continuous positive airway pressure (CPAP), aggressive pulmonary toilet, early ambulation, and a multimodal approach to pain control that averts narcotic-induced respiratory depression.
Renal Anatomy
Authors: Taco Erika , Noguera Edward
Published: March 2023

The kidneys are organs that are very sensitive to hypoxic injury. Prolonged hypoxemia or toxicity to renal tissues can quickly develop apoptosis and cell death. Low cardiac output states, hypovolemia, uncontrolled hemorrhage, aortic clamping, and some medications and intravenous contrast agents are risk factors for the development of acute kidney injury.
Complications of Transurethral Resection of the Prostate
Authors: Justinger Jacob , Abouhassan Soozan S.
Published: March 2023

Transurethral resection of the prostate (TURP) is a common urologic procedure. Despite this, it presents several challenges to the anesthesia provider. As benign prostatic hyperplasia (BPH) is a disease of aging, TURP is frequently performed in an older population with comorbid conditions. The surgical technique poses risks, notably the absorption of large volumes of irrigation fluid. While various irrigation fluids are used, each presents its own risk profile. The constellation of symptoms resulting from the absorption of irrigation solution is known as TURP syndrome. The anesthesia provider should be on watch for TURP syndrome as it can result in a hypervolemic hyponatremia manifesting in profound neurologic consequences.
Polycythemia
Authors: Shapiro Victoria , Brosnan Heather
Published: March 2023

Polycythemia is a disease of elevated hematocrit or hemoglobin. Primary polycythemia is most often due to polycythemia vera, whereas secondary causes tend to be due to chronic states of hypoxia leading to elevated erythropoietin (EPO) levels, such as sleep apnea, obesity hypoventilation syndrome, chronic obstructive pulmonary disease (COPD), and cyanotic heart lesions. Hyperviscosity of the blood leads to poor flow dynamics, decreased tissue oxygenation, and increased thrombotic risk. Patients with polycythemia can have paradoxical hemorrhage as a result of acquired von Willebrand disease and platelet dysfunction secondary to thrombocytosis. Thus, it is important to do a thorough evaluation prior to surgery. A preoperative hematocrit of less than 45% is ideal, and the anesthesiologist should remain vigilant: avoid hypoxia, maintain volume status, and mitigate deep vein thrombosis (DVT) risk.
Thrombocytopenia and Thrombocytopathy
Authors: Shapiro Victoria , Chang Michael
Published: March 2023

Hemostasis and coagulation are parts of a complex process of bleeding cessation requiring a combination of vascular factors, platelets, and plasma coagulation factors. Through the continuum of primary and secondary hemostasis, a hemostatic plug is formed via platelet aggregation and stabilized by products of the blood coagulation cascade. Patients with disorders affecting the platelet quantity and quality have increased risk of perioperative hemorrhage. These disorders may be congenital or acquired, but ultimately may necessitate platelet transfusions to achieve hemostasis. For patients with thrombocytopenia or platelet dysfunction undergoing surgeries, the bleeding risk of the procedure should be assessed, as some procedures are more invasive and prone to bleeding than others.
Congenital and Acquired Factor Deficiencies
Authors: Hughes Meghan C. , Abd-Elsayed Alaa
Published: March 2023

Coagulation factor deficiencies can be either congenital or acquired. Hemophilia is possibly the most recognized type of factor deficiency, but it is certainly not the only one. Hemophilia comes in three forms, two of which are quite well known: A and B. Hemophilia A is an inherited factor VIII deficiency and is an X-linked recessive disorder. Hemophilia B is an inherited deficiency of factor IX and is also an X-linked recessive disorder. The lesser known, hemophilia C, is an inherited deficiency of factor XI. Acquired factor deficiencies are most commonly the formation of an autoantibody to factor VIII; they are sometimes referred to as “acquired hemophilia”; however, in an effort to minimize confusion, they are typically referred to as “acquired factor inhibitor” or “acquired factor deficiency.”
Pancreas Transplantation
Authors: Maria Gorneva , Anna Tzonkov
Published: March 2023

Pancreas transplantation is a surgical treatment for complicated cases of diabetes mellitus type 1 and occasionally type 2. Patients with a history of frequent, severe metabolic complications (marked hypoglycemia or hyperglycemia, ketoacidosis) and failing insulin management are typical candidates. The procedure was first performed in humans in 1966. Now, due to development of better immunosuppressive agents (specifically cyclosporine and anti–T-cell antibodies), advanced surgical techniques, and better patient selection, more than 700 of various types of pancreatic transplants are performed yearly in the United States alone. Most patients receive a pancreas from a cadaver donor, but donation by a living related donor is also possible. The goals of transplantation are to restore glucose-regulated endogenous insulin secretion, arrest the progression of the complications of diabetes, and improve quality of life. There are several types of such treatment as follows: pancreas transplant alone (PTA), simultaneous pancreas-kidney transplant (SPK), pancreas after kidney transplant (PAK), and islet transplant (developing technology). SPK is the most common type of transplant, which is performed on patients with diabetes type 1 complicated by end-stage renal disease. Complications following pancreas transplant occur more frequently than in other abdominal solid organ transplants. Although major complications following pancreas transplant are uncommon, several, including pancreatitis, exocrine duct leaks, and pancreatic pseudocysts, are unique to this transplant. The most common reason for graft failure overall is immunologic rejection. Both pancreas and islet transplantation require lifelong immunosuppression to prevent rejection of the graft.
Motor Neuron Diseases
Authors: Dalton Allison K.
Published: March 2023

Motor neuron diseases are a group of rare, heterogenous disorders characterized primarily by skeletal muscle weakness. Diseases are classified as affecting primarily upper motor neurons, lower motor neurons, or both. Upper motor neuron diseases are characterized by muscle weakness, hyperreflexia, and spasticity, while lower motor neuron diseases are characterized by weakness, muscle atrophy, and fasciculations. Disease course is typically progressive. Age of onset, symptom severity, and disease course differ depending on the exact diagnosis and neurons affected. Patients with advanced disease may suffer from respiratory, pharyngeal, and skeletal muscle weakness, which have significant implications for preoperative, intraoperative, and postoperative management.
Congenital Myasthenic Syndromes
Authors: Sam Sabrina S. , Ragheb-Mueller Nawal E.
Published: March 2023

Congenital myasthenic syndromes (CMSs) are rare disorders caused by hereditary mutations leading to an abnormal response to acetylcholine. There are three main categories of CMS: presynaptic, postsynaptic, and synaptic. A CMS is characterized by fatigable muscle weakness, but severity and onset of symptoms can vary greatly. Early onset corresponds to more severe features. CMS is diagnosed with electrodiagnostic testing and a Tensilon test. Genetic testing is required to differentiate between the subtypes. CMS does not respond to steroids or immune modulation as it is not an autoimmune disorder. The management of CMS is dependent on the genetic mutation. CMS can also be exacerbated by many commonly used drugs. It may be prudent to avoid muscle relaxation for intubation if the surgical procedure allows it.
Cancer Pain
Authors: Vorenkamp Kevin E. , Abd-Elsayed Alaa
Published: March 2023

Pain is one of the most troubling symptoms for the nearly 17 million cancer patients in the United States. For many patients, traditional medications and treatments are not effective, and they are severely debilitated by their pain, causing needless suffering at the end of life. Overall, a recent meta-analysis demonstrated a prevalence rate of moderate or severe pain in 38% of all patients with a cancer diagnosis, but these rates are nearly doubled for patients with advanced, metastatic, or terminal cancer diagnoses. In this chapter, pharmacological approaches incorporating the World Health Organization (WHO) analgesic ladder are reviewed and inherent limitations discussed. Interventional treatment strategies, including neurolytic blocks and neuraxial infusions, are described, including appropriate patient selection.
Complex Regional Pain Syndrome
Authors: Mauer Kim , Abd-Elsayed Alaa
Published: March 2023

Complex regional pain syndrome type 1 and type 2 were formerly called reflex sympathetic dystrophy type 1 and type 2. Type 2 reflex sympathetic dystrophy (RSD) was also more commonly referred to as “causalgia.” While the terminology has changed, the disease condition has not. Complex regional pain syndrome types 1 and 2 are very similar. The syndrome is difficult to diagnose and treat. It usually affects an arm or a leg. Most of the clinical characteristics are shared. The understanding is continuing regarding this sympathetically mediated pain. In addition, new therapies for it are constantly being discovered, and there has been newer diagnostic criteria, the Budapest criteria.
Neuraxial Opioids
Authors: Jenkinson Robert H. , Abd-Elsayed Alaa
Published: March 2023

Opioid administration into the epidural or intrathecal space is a commonly employed technique for both acute and chronic pain management. Epidural and intrathecal opioids can provide profound analgesia in significantly smaller doses than if administered parenterally. Opioids are commonly coadministered with other medications, such as local anesthetics and α-adrenergic agents, in order to produce profound levels of analgesia. Though neuraxial opioids can provide safe and effective pain control, their clinical pharmacology is complex. Therefore, a careful understanding of key underlying principles is needed in order to choose the appropriate opioid agent, neuraxial route of administration, and dose for each clinical situation.
World Health Organization (WHO) Analgesic Ladder
Authors: Jenkinson Robert H. , Abd-Elsayed Alaa
Published: March 2023

The 1986 World Health Organization (WHO) report on cancer pain management included an analgesic ladder and was a landmark publication. The report offered a logical, simple and sequential approach to analgesic escalation that could be implemented even in low-resource areas. The use of the analgesic ladder for chronic noncancer pain, which was not the intent of the WHO guidelines, remains a controversial subject. Modifications that more strongly incorporate interventional therapies as well as integrative medicine therapies have garnered substantial support. However, the principles of sequential escalation based on analgesic strength, pain severity, and response to prior therapy are still applicable.
Cardiovascular System
Authors: Iana Bilga , Gwam Chike
Published: March 2023

An understanding of the unique characteristics of the pediatric cardiovascular system is essential for the safe delivery of anesthetic care to the pediatric patient. Knowledge of fetal development, fetal circulation, the transition to extrauterine life, as well as age-specific physiological, hemodynamic, and functional differences of the pediatric cardiovascular system is crucial in the anesthetic management of neonates and young children.
Fetal Hemoglobin
Authors: Chung Alex Y. , Carollo Dominic S.
Published: March 2023

Fetal hemoglobin (HbF) is a physiologic variant of the adult hemoglobin (HbA) protein. It is primarily present in the fetus. HbA has a lower oxygen affinity than HbF. A newborn’s hemoglobin transitions from HbF to HbA with 70% HbF at 40 weeks’ gestational age to almost 0% at 6 months after birth. Transfusion with HbA blood or premature birth can affect the rate and timing of this transition. The change in proportion of HbF will affect the degree of oxygen saturation of hemoglobin for a given partial pressure of oxygen due to the difference in the oxygen-hemoglobin dissociation curve. A thorough history and careful evaluation of monitoring devices allow the anesthesiologist to optimize oxygen delivery perioperatively.
Prematurity
Authors: Gyorfi Michael J. , Abd-Elsayed Alaa
Published: March 2023

Approximately 12.5% of births in the United States are preterm. This is defined as a birth occurring before 37 weeks of gestation. The risk of mortality and morbidity are inversely related to gestational age. Preterm infants weighing 1500 g or less are termed as having a very low birthweight; this is associated with numerous complications. Preterm neonates contribute disproportionately to infant morbidity and healthcare costs. Short-term complications include respiratory distress syndrome (RDS), necrotizing enterocolitis (NEC), and intraventricular hemorrhages. Preterm infant complications pose numerous challenges for proper administration of anesthesia. Challenges range from managing a delicate respiratory system to assessing pain control in nonverbal neonates.
Altered Uptake/Distribution of Intravenous and Inhalation Anesthetics
Authors: Sinton Jamie W.
Published: March 2023

Intravenous drug doses in pediatrics are often weight based, assuming a linear relationship between clearance kinetics and weight. This is strategy is flawed as metabolic processes are not linearly related to body mass. Rather, they are related to the combination of organ maturation, changes in body composition with somatic growth, and organ maturation, such as glucuronide conjugation. Further, these processes are difficult to study without practical methods of measuring pharmacodynamic effects of drugs in young children. In contrast, inhalational anesthetics are quite insoluble and undergo negligible amounts of metabolism. In this chapter, the focus is on rate of uptake and impact on the neonatal myocardium.
Noncardiac Surgery
Authors: Sinton Jamie W.
Published: March 2023

Children with heart disease who undergo noncardiac surgery present substantial anesthetic risk. The incidence of congenital heart disease has been estimated as 6/1000. Related anesthetic risks include cardiac lesions, inpatient versus outpatient setting, type of surgery, surgical approach, and postoperative disposition. Robust literature has frequently pointed to the following as involving high risk: single ventricle, pulmonary hypertension, Williams-Beuren syndrome, and cardiomyopathy (dilated, hypertrophic, restrictive). While risk data are robust, management tips and guides are rarely evidence based. Mitigating risk preoperatively may improve outcomes in this population.