bluuebunny/crossref_metadata_2025 huggingface dataset:
Actions of Compact and Discrete Quantum Groups on Operator Systems
Authors: De Ro Joeri , Hataishi Lucas
Published: May 2024

We introduce the notion of an action of a discrete or compact quantum group on an operator system, and study equivariant operator system injectivity. We then prove a duality result that relates equivariant injectivity with dual injectivity of associated crossed products. As an application, we give a description of the equivariant injective envelope of the reduced crossed product built from an action of a discrete quantum group on an operator system.
Military Atrocity, National Identity, and Warrior Masculinity on Trial
Authors: Partis-Jennings Hannah
Published: May 2024

The article explores different and contested narrations surrounding alleged war crimes by former Australian soldiers in Afghanistan, with a particular focus on one veteran with considerable public standing, Ben Roberts-Smith. It shows how certain stories told to identify and condemn acts of extra-legal violence, work to separate these acts out as exceptional and different from wider violence in war, and thus support the normalization and justification of war violence more broadly. However, it also demonstrates how attention to the role of race and gender in shaping meaning-making around violence in war disrupts the idea that extra-legal violence is exceptional. It finally articulates a thematic reading of how allegations of war crimes are interpreted and rejected in discourses of support for Roberts-Smith expressed on Facebook. It shows how different constructions of extra-legal violence at different sites each contribute to the ways that meaning might be drawn from acts of violence into narrative formulations about liberal war and offer important insights into the political configurations surrounding war crimes and their relationship to national identity and liberal militarism. The article thus contributes conceptually and empirically to debates surrounding the politics of war crimes.
Taking to Kill: The Lethality of Hostage-Taking in Civil War
Authors: Welsh Blair
Published: May 2024

Hostage-taking is often portrayed as non-lethal violence. Upon the receipt of demands, victims are expected to be released alive. Despite this, large evidence points to egregious forms of hostage killing in civil war. Why, then, do some organizations kill hostages? I argue organizations execute hostages as part of a punitive governance strategy in their areas of operation. Hostage-taking and killing can be used as a corrective action to exercise control over the population. Victims accused of acts that undermine the rebel regime are more likely to be killed than those taken for other purposes. I test the theory in the case of the Islamic State in Iraq with novel and granular data on violence in the thirty-one districts the organization governed between 2013 and 2018. The findings unveil important insights for policy and research.
Diagnosis of an unusual orbital abscess following sub-Tenon's steroid injection: a case report
Authors: Gupta Isha , Moussa Elliott , Motupally Karun , Morris Sharon
Published: May 2024

Orbital abscesses are caused by infection within or near the orbit and show obvious signs of pain, proptosis and raised inflammatory markers. Diagnosis is based on clinical features and radiological imaging, and requires early antibiotics and often surgical drainage to save vision. Sub-Tenon’s injections of triamcinolone acetonide (TA) have caused localized infections in previous reports, which have responded to therapeutic interventions. Here we report a case where a delayed presentation of an orbital abscess secondary to sub-Tenon’s TA for persistent post-operative cystoid macular oedema, without obvious signs of infection, rapidly progressed to cause orbital compartment syndrome. Despite treatment, the patient lost complete vision in the affected eye. This case discusses the rare and unusual cause of abscess formation and a diagnostic dilemma.
Recurrent aneurysmatic bleeding of pancreaticoduodenal aneurysm due to median arcuate ligament syndrome: a case report
Authors: Hofmann Kyra , Lareida Anna , Bächler Thomas , Breitenstein Stefan , Kambakamba Patryk
Published: May 2024

Median arcuate ligament syndrome (MALS) involves coeliac artery compression, causing a range of symptoms from chronic pain to life-threatening complications. This case features a 52-year-old patient with recurrent retroperitoneal bleeding from MALS-related inferior pancreaticoduodenal artery aneurysms (PDAAs). Emergency interventions, including surgical bleeding control, angioplasty, percutaneous drainage, and median arcuate ligament release, were conducted. The case highlights challenges in diagnosing and managing MALS-related PDAA, emphasizing the importance of early identification and tailored interventions based on clinical symptoms and imaging. Surgical intervention to release the ligament is the primary treatment, with considerations for prophylactic intervention in PDAA cases. Lack of established PDAA management protocols underscores the need for prompt intervention to prevent complications. In conclusion, this report stresses the association between MALS and PDAA, advocating for early identification and tailored management to mitigate complications.
Radiolucent cerclage for humerus fractures: beware of radial nerve injury—a case report
Authors: Dadabhoy Maria , Cuthbert Rory , Sugand Kapil , Vusirikala Anuhya , Fox Michael , Panagiotidou Anna , Sinisi Marco , Quick Tom
Published: May 2024

A 73-year-old woman was referred to a National Centre for Peripheral Nerve Injury with a post-operative left radial nerve degenerative lesion following open reduction and internal fixation of a proximal third humerus fracture using radiolucent Arthrex FiberTape® Cerclage as an adjunct to plating to improve stability. Intra-operative photographs illustrate compression of the radial nerve under the cerclage construct. Use of radiolucent cerclage for humerus fractures is increasing with modern systems capable of withstanding an ultimate load of 4300 N. We highlight the risk of debilitating neurological injury when not deployed safely and describe anatomical high-risk zones for injury. We emphasize the impact of delay in diagnosis and treatment.
Transducers, Regulators, and Medical Gas Cylinders
Authors: Aquino Ben
Published: May 2024

Transducers, regulators, and medical gas cylinders are ubiquitous in anesthesia, and this chapter examines their principles and most common uses. Transduction is the conversion of a signal from one form of energy to another, a principle which underlies many of the commonly used monitoring devices in anesthesiology. Multiple safety features exist as various points in the anesthesia machine to ensure that gases are administered to the patient in a safe and manageable way. Among these are various pressure regulators that ensure that gases, from either a master supply or a gas cylinder, enter the patient circuit at physiologically safe pressures. Gas cylinders themselves contain many safeguards, including unique attachments to the anesthesia machine, and distinct color codes unique to each gas.
Properties of Liquids, Gases, and Vapors
Authors: Aquino Ben
Published: May 2024

The basic properties of liquids, gases, and vapors are important for the anesthesiologist, because they relate to the processing and delivery of anesthetic gas, as well as the movement of these drugs once they enter the body and exert their effects. Every substance has a critical temperature (above which the substance is only a gas) and a critical pressure (above which the substance is only a liquid). At physiologic conditions volatile anesthetic gases are well below both of these, and as a result, they can exist in both liquid and gas (vapor) form. The anesthetic vaporizer works on the volatile anesthetic in between the liquid and vapor phases and delivers gas to the patient in a consistent and safe way. Once the gas enters the respiratory system and is absorbed, it does so by diffusion and bulk flow. At this point it dissolves to varying degrees in various compartments in the body, including blood, fat, and air. Its solubility in each of these compartments affects its pharmacokinetics and determines its distribution within the body.
Portable Ventilation Devices
Authors: Chawla Pradeep R. , Bang Jason
Published: May 2024

Portable ventilation devices are commonly used on a day-to-day basis. The most well-known portable ventilation device is known as an AMBU bag. There are two main classes of portable ventilation devices: self-inflating systems and flow-inflating systems. There are a multitude of self-inflating systems available; however, they all have similar components. An important component is the non-rebreathing valve, which ensures that expired gas is not mixed with fresh inspired gas. Flow-inflating systems can be used as well; the most common are two subtypes of Mapleson systems. These devices may lack the same tactile feel as a bag on a normal anesthetic circuit and can cause barotrauma.
Carbon Dioxide Absorption
Authors: Mahboobi Sohail K. , Mahmood Faraz
Published: May 2024

Carbon dioxide (CO2) absorbers are used routinely in anesthesia circle systems to remove CO2 from exhaled respiratory gases and to avoid rebreathing. The absorption is based on chemical reactions of CO2 with the ingredients of absorbents, usually calcium hydroxide [Ca(OH)2]. Strong bases (NaOH and KOH) are added as catalysts to speed up the reaction. These reactions result in the production of calcium carbonate, heat, and water. Indicator dyes are added to change color on exhaustion due to a drop in absorbent pH. The presence of bases also results in compound A production with sevoflurane and carbon monoxide with desflurane in certain conditions. These reactions can cause excessive heat production when sevoflurane is used with a desiccated base containing absorbents like soda lime. The indicator dye is not always reliable, as it can change color back to normal with fluorescent light exposure. The newer absorbents either do not contain bases (lithium based and Amsorb) or contain a very low amount to avoid these issues.
Neurologic Function Monitors
Authors: Latimer Dustin , Kaye Alan D.
Published: May 2024

Neuromonitoring is important to assess the functional neurologic integrity of a patient during surgery by a variety of different monitoring modalities. Electroencephalography and electromyography are presented as two potential monitoring modalities. Narcotics, such as fentanyl, ketamine, benzodiazapenes, and bartbituates properties, are examined as they relate to neuromonitoring. Inhaled anesthetic properties and their relation to neuroactivity are discussed as well. Each agent possesses differing properties to highlight the advantages and disadvantage of using certain compounds rather than others. Although there are many types that target different sites, this chapter highlights some of the most significant in clinical practice.
Fluid Warmers and Autotransfusion Devices
Authors: Guruswamy Jayakar , Rao Akshatha Gururaja
Published: May 2024

Inadvertent perioperative hypothermia is common but preventable. General and regional anesthesia decreases core temperature by 0.5–1.5°C. In-line warming devices should be used to warm fluids and blood products to 37°C before administration during the intraoperative period. Fluid warmers are classified as a dry warming system, countercurrent heat exchanger, water bath system, convective air system, and insulators. Delivery of heated fluid depends on warming method, flow rate, and length of tubing between warmer and patient. Ranger fluid warmers are commonly used in operating rooms (ORs). They utilize dry heat, and fluid passes through disposable set that fits into warming dock. Warming cabinets prewarm IV fluid bags. They are simple, cheap, and maintain warmer core temperature during short surgeries. Autologous blood transfusion includes collection and reinfusion of patient’s own blood during surgery and immediate postoperative period. Intraoperative cell salvage (ICS) is useful when excessive blood loss is anticipated. It reduces or avoids allogenic red cell transfusion, is useful in rare blood types/antibodies with restricted blood availability, in patients who decline allogenic blood transfusion, severe preoperative anemia with high bleeding risk, and in trauma surgery. Relative contraindications include blood contamination by bacteria, bowel content, tumor cells, amniotic fluid, sickle cell disease, and medical contaminants in blood (hemostatic agents, prep solution, bone cement). ICS steps include collection of blood from the surgical field in a reservoir while mixing with an anticoagulant. Red cells are then separated by centrifugation, washed with 0.9% saline, and bagged for transfusion via standard blood administration set with filter.
Defibrillators
Authors: White Peggy , Giordano Chris
Published: May 2024

The application of an electrical current through the chest wall will cause erratic myocardial electrical activity that will depolarize the electrical system within the heart, which will permit resynchronization of the myocytes. That creates an organized electrical discharge, myocardial contraction, and a subsequent perfusable rhythm. External defibrillators can deliver this electrical charge through the application of two paddles, and the magnitude of the electricity applied to the chest wall should be balanced between minimizing myocardial damage and maximizing the likelihood of electrical reorganization with the first shock. This chapter will focus on basic physics and anesthetic implications of these devices.
Impact of Renal Disease
Authors: Bui Eileen , De Ranieri Aladino
Published: May 2024

Perioperative renal function is an important aspect to consider for anesthesiologists, as the kidneys are responsible for or are involved in a number of essential functions. These include solute regulation and transport, intravascular osmolality and water balance, excretion of the end products of metabolism and drugs, neurohumoral functions, hematopoiesis, and bone remodeling. Renal function is typically evaluated through a combination of laboratory physiologic parameters. Those parameters in turn can be used to determine the location of the renal dysfunction. Consequently, the metabolism of many medications is correlated with renal function, and understanding their relationship is important in the perioperative care of a patient.
Drug Interactions
Authors: Carroll Turpin Michelle A. , Cornett Elyse M.
Published: May 2024

Drug interactions can be both useful and dangerous, and an anesthesia regimen necessitates the combination of numerous medications. Physicians should recognize possible drug interactions related to their patient’s treatment to best treat them and prevent unwanted side effects. Drug interactions can be categorized in three ways: pharmacodynamic, pharmacokinetic, or pharmaceutical. Pharmacodynamic interactions refer to an agent’s site of activity. Pharmacokinetic interactions occur when one agent influences the absorption, distribution, metabolism, and/or elimination of another agent. Pharmaceutical interactions are not related to the pharmacological properties of the interacting drugs but are the result of chemical or physical incompatibilities.
Drug Reactions
Authors: Kapp Daniel Gonzalez
Published: May 2024

Adverse drug reactions are any undesirable effects of a drug, which primarily arise in one of two ways: as a consequence of the drug’s underlying pharmacology, or as an unpredictable occurrence. Adverse drug reactions can be classified as either Type A, when the reaction is reasonably associated with the drug’s mechanism of action and is usually dose related; or Type B, when the reaction is idiosyncratic. Anaphylactic and immediate hypersensitivity reactions are Type I reactions; in these cases, antigens interact with IgE antibodies leading to mast cell activation and the release of inflammatory mediators. Treatment of anaphylaxis begins with discontinuation of the suspected trigger and stabilization of the patient’s airway. The primary drug treatment for anaphylaxis is epinephrine, as it is critical for the reversal of bronchospasm and management of laryngeal edema, cardiovascular compromise, and severe hypotension.
Intravenous Opioid Anesthetics
Authors: Parker Nicholas M.
Published: May 2024

Opioids provide excellent analgesia and sedation with minimal cardiovascular effects. Intravenous opioids may be used to induce anesthesia within seconds, may be used as a primary or adjunctive maintenance anesthetic, and help provide pain control postoperatively. Opioids cause respiratory depression, so mechanical ventilation must be available. A variety of opioids is available, each with a unique place in therapy. Opioid-induced constipation is a common postoperative complication. Consideration must be given at every stage of care to opioids’ potential for addiction, dependence, and overdose. Naloxone is increasingly available and is appropriate to prescribe for most patients discharging with an opioid prescription.
Thiopental
Authors: Nemergut Greta
Published: May 2024

Thiopental is a rapid-acting barbiturate used as an induction agent for anesthesia. Its lipid solubility allows the drug to quickly cross the blood-brain barrier and exert its effects. These effects only last about 30 minutes as it also quickly distributes to other body areas where it becomes inactive. When given as a slow intravenous (IV) push, adverse events are minimized, but it can cause mild hypotension and respiratory depression. Hypotension can worsen in patients with preexisting cardiac disease, and all adverse events can worsen if the drug is given too quickly or at high doses. Because of the alkaline nature of the drug, severe tissue damage can occur if accidentally give intra-arterially or if the drug is extravasated into surrounding tissue. Thiopental is no longer available in the United States, and propofol has replaced the agent in most clinical practice.
Sodium Bicarbonate
Authors: Nemergut Greta
Published: May 2024

Sodium bicarbonate is an alkalinizing agent used to restore acid-base balance and has been used with some regional and local anesthetic agents to reduce pain on administration and to enhance the onset of action of the agent. By increasing the pH of the local anesthetic agent, sodium bicarbonate aids the movement into lipid membranes that can allow for an enhanced effect and a reduction of pain at the administration site. It has been found that sodium bicarbonate can enhance the effect of epidural anesthetics, but data do not support this effect in peripheral nerve blocks.
Nicardipine and Other Antihypertensive Medications
Authors: Walia Anureet , Sharma Archit
Published: May 2024

Antihypertensives are the medication group that are used to lower the patients’ blood pressure. A variety of oral and parenteral agents are used for this purpose. The choice of agent and the dosage depend on the patient’s condition and the hospital formulary. Various classes of medications are available that serve to decrease a patient’s blood pressure, working in different methods. This chapter discusses the different agents, their clinical effects, their pharmacokinetics, and their pharmacodynamics. Nicardipine is a medication that belongs to the class of calcium channel blockers, which relaxes the blood vessels, and is used to treat high blood pressure and angina.
Medication-Assisted Opioid Withdrawal
Authors: Peng Huanhuan , Conermann Till
Published: May 2024

This chapter on medication-assisted opioid withdrawal, also called detoxification, discusses that the goal of treatment is not to achieve total abstinence from opioids, but rather to safely transition a patient with opioid use disorder to an alternative, safer medication-assisted treatment, as well as to reduce the severity of withdrawal symptoms and successfully switch a patient to a maintenance medication regimen in order to prevent relapse. It reviews maintenance pharmacotherapy for opioid use disorder, using an approved opioid agonist methadone, a partial agonist/antagonist buprenorphine, and an antagonist naltrexone. It also discusses how naltrexone as a full agonist can be used for full detoxication, whereas methadone and buprenorphine, relying on full and partial opioid agonism, respectively, result in a state of continued physiological dependence. Also reviewed are alpha-2 adrenergic agonists such as clonidine and lofexidine, often used to mitigate the severity of withdrawal symptoms. The efficacy of buprenorphine and methadone are comparable, and both are superior to clonidine and lofexidine in supervised withdrawal. This chapter includes DSM-5 criteria for opioid use disorder and withdrawal including the clinical opioid withdrawal scale.
Agents and Techniques in Pediatric Anesthesiology
Authors: Dooley F. Cole , Streetzel Charlotte
Published: May 2024

The safe practice of pediatric anesthesiology requires a thorough understanding of the physiologic and pharmacologic mechanisms involved with common medications and scenarios. From the operative environment to the physiologic responses, to the metabolism and clearance of medications, there are significant differences one should expect when treating a pediatric patient compared to an adult. Furthermore, within the pediatric population, patients can be subdivided further into neonates, infants, children, and adolescents, each with varying metabolic and physiologic parameters that need to be accounted for. In this chapter, common induction techniques and agents will be discussed, focusing on key details that distinguish this population and are crucial to understand in order to provide safe care. The chapter will review agents that are preferentially toxic to children, as well as those agents which have varying sensitivities, metabolism, and contraindications when compared to their use in adults.
Intraocular Pressure
Authors: Teixeira Camila , Minear Steven
Published: May 2024

Subtle intraocular pressure (IOP) elevation during surgery plays a significant role in the pathogenesis of perioperative ocular morbidity, particularly in patients with preexisting eye disease. The balance between the aqueous humor production and outflow rate is the main predictor of IOP. Resistance to the aqueous humor outflow, as presented in glaucomatous patients, can rapidly increase IOP and impair blood flow to retina and nerve optic. Perioperative visual loss (POVL) is an uncommon but catastrophic complication. Surgical or anesthetic features that combine either to decrease the arterial pressure or to elevate the IOP can reduce intraocular perfusion pressure (IOPP). Vigilance in controlling IOP and safeguarding IOPP is therefore of critical importance when planning the anesthesia management of patients with glaucoma disease.
Depression
Authors: Schwartz Ruben , Viswanath Omar
Published: May 2024

Depression is a highly researched topic due to its increased prevalence throughout the patient population. Disruption in neurochemical substrates such as serotonin, dopamine, epinephrine, and others have all been implicated as decreased in depressed individuals. Many of these patients have been started on antidepressant medications as a result. Anesthesiologists must know the potential interactions these medications might have with the anesthetic regimen. Some of the common antidepressants prescribed include selective serotonin reuptake inhibitors (SSRIs), serotonin-norepinephrine reuptake inhibitors (SNRIs), tricyclic antidepressants (TCAs), and monoamine oxidase inhibitors (MAOIs). Understanding the pharmacology of these medications is vital to provide a safe environment for patients.
Chronic Obstructive Pulmonary Disease
Authors: Hussain Shahrose , Fikry Karim
Published: May 2024

Chronic obstructive pulmonary disease (COPD) is chronic, irreversible airflow limitation due to airway and/or alveolar abnormalities caused by noxious particles and/or developmental abnormalities associated with significant morbidity and mortality. COPD commonly presents with dyspnea and a chronic, productive cough. A COPD exacerbation is an acute worsening in respiratory symptoms from baseline, necessitating additional therapy. Diagnosis of stable COPD is confirmed by spirometry, whereas an acute exacerbation is diagnosed clinically. Treatment involves smoking cessation, inhaled treatments, appropriate oxygenation, and pulmonary physiotherapy. Anesthetic management includes a thorough preoperative evaluation ensuring optimal pulmonary function, utilizing regional techniques if possible, preventing bronchoconstriction, and optimizing air flow.
Minimally Invasive Cardiac Surgery
Authors: Gray Ellyn , Sharma Archit
Published: May 2024

Minimally invasive cardiac surgery has been rapidly evolving over the past few decades, and it is important for anesthesiologists to be aware of the range of approaches and special considerations for each surgery. A minimally invasive approach has numerous advantages, including less inflammation, less pain, avoiding bypass, and avoiding a complete sternotomy. Anesthesiologists facilitate this approach by providing optimal surgical settings beginning with lung isolation, confirming cannula placement, and cardioplegia delivery. However, the concern remains and is related to patient safety, prolonged surgical times, and reduced surgical exposure, leading to possibility of suboptimal treatment. It is critical to be prepared for the possibility of an emergent sternotomy and crashing onto cardiac bypass being necessary at any point during the procedure.
Anesthetic Choice in Reduced Renal Function
Authors: Tian Ling , Nguyen Christina T.
Published: May 2024

This chapter focuses on overall perioperative concerns for a patient with reduced renal function about to undergo anesthesia. It briefly discusses the pathophysiology of renal disease and risk factors to help identify patients who may need special consideration. It contains a comprehensive table discussing the renal considerations for commonly used anesthetics, as well as explanations for the mechanisms by which reduced renal function affects anesthetics. It concludes with a brief overview for prevention, management, and treatment of perioperative renal failure, as well as perioperative considerations for at-risk patients.
Fluid-Replacement Strategies and Controversies
Authors: Conhaim Jay I. , Lemmink Gretchen A.
Published: May 2024

One’s perspective on intraoperative fluid management is stereotypically determined by one’s location in relation to the surgical drapes. However, just as stereotypes can be wildly misleading, so can the perspective that there is one type of resuscitation that will apply to all surgical patients. Perioperative fluid replacement strategies must be patient centered and must account for a variety of factors, including patient comorbidities, type of surgery, duration of surgery, type of anesthesia, and presence or absence of intraoperative complications. The ultimate goal of intravenous (IV) fluid administration is to optimize a patient’s preload, thus maximizing their cardiac output, tissue perfusion, and oxygen delivery. Methods of determining the optimal fluid volume needed to achieve these goals have changed dramatically in the past decade. Static mathematical calculations have given way to real-time, continuous physiologic assessment. Preoperative fasting guidelines are now evolving into preoperative hydration guidelines. Even the optimal type and composition of resuscitative fluids are now better understood. Despite the numerous recent changes in perioperative fluid strategies, a new and evidence-based path toward perioperative IV fluid resuscitation is emerging and is illustrated in this chapter.
Intravenous Regional Anesthesia
Authors: Scholzen Elizabeth , Klesius Lisa
Published: May 2024

Intravenous regional anesthesia (IVRA), also known as a Bier block, provides anesthesia of the entire extremity and can be used as the primary anesthetic for surgeries involving the upper extremity. Dilute local anesthetic (typically 0.5% lidocaine) is administered intravenously after a tourniquet is placed on the extremity. Currently, this technique is most commonly performed as a modified forearm technique that uses less local anesthetic. Contraindications include patient refusal as well as abnormalities of the extremity that is to be anesthetized including crush injury, scleroderma, or infection. Local anesthetic toxicity is the feared complication of IVRA but, fortunately, is rare.
The Surgical Airway
Authors: Kendrick Julia , Kaye Alan D.
Published: May 2024

Orotracheal and nasotracheal intubation is performed thousands of times daily for a variety of reasons. However, related to a number of factors, such as difficult patient anatomy, excessive blood in the mouth or nose, massive facial trauma, or airway obstruction, surgical airways may be required to secure an airway. A tracheostomy tube or endotracheal tube placed during a cricothyroidotomy performed under emergency circumstances can be temporarily placed but should be converted to tracheostomy for long-term airway management. Needle cricothyrotomy with transtracheal jet ventilation is the surgical airway technique of choice in the pediatric population. Tracheostomy requires a higher level of skill, is commonly preferred for long-term management, and is usually performed by a surgeon in a controlled setting.
Supraglottic Secretion Suctioning and LASER Safety Protocols
Authors: Connolly Matthew T.
Published: May 2024

Supraglottic secretion and LASER safety protocols both deal with airway safety management and are essential parts of anesthesia care. The former is used in daily prior to extubation and consists of use of either a hard plastic Yankhauer or flexible suction catheter. Avoidance of oropharyngeal soft tissues and proper timing of suction are necessary to prevent trauma or any agitation that could lead to premature extubation, laryngospasm, or a sympathetic response that could be detrimental to the surgery. Intraoperative use of LASERs (light amplification by stimulated emission of radiation) is becoming more common in the operating room, and knowledge of the types of procedures that use LASERs, as well as the risks and anesthetic implications of the various types of LASERs, is necessary to provide safe anesthesia. Anesthesia for these procedures can be employed through moderate sedation techniques or with LASER-safe endotracheal tubes.
Acute Postoperative and Posttraumatic Pain
Authors: Johnson Savion D. , Starr Brian M.
Published: May 2024

Treatment of acute postoperative and posttraumatic pain is an integral piece in the care of the surgical patient, as inadequate pain control can result in increased morbidity and mortality. In contrast, effective postoperative pain management not only improves patient satisfaction, but also leads to earlier mobilization, decreased cardiopulmonary complications, improved recovery, and shorter length of hospital stay. In addition to systemic opioids, a variety of modalities are used for acute postoperative analgesia, which include epidural analgesia, neuraxial opioids, peripheral nerve blocks, patient-controlled analgesia, and the use of oral medications and infusions as part of multimodal analgesia regimens.
Vascular Injuries
Authors: Youssef Yasser M. A. , Ragheb-Mueller Nawal E.
Published: May 2024

Anesthesia-related vascular access injuries range from arterial/venous thrombosis, thrombophlebitis, sheared catheters, and inadvertent intra-arterial injections to air emboli, cardiac/vascular perforations, and pulmonary artery rupture. This chapter addresses the most significant injuries associated with these procedures. Although peripheral venous and arterial cannulation is relatively safe, significant complications may lead to iatrogenic injury and liability for anesthetists. Claims for peripheral vascular catheter complications comprise 2% of all those in the ASA Closed Claims database; 91% of these are related to intravenous (IV) and 9% to arterial catheters. Anesthesia providers should recognize any early signs of peripheral intravenous extravasation, as delayed management may lead to compartment syndrome. Invasive arterial monitoring is associated with risks of bleeding, hematoma, pseudo-aneurysm, infection, nerve damage, and distal limb ischemia. Early recognition of distal ischemia and proper management can prevent surgical exploration or devastating loss of extremity. Vascular injuries from central venous catheterization range from minor complications, such as local hematoma, to serious consequences, including cardiac perforation or thromboembolism. Pulmonary artery rupture during pulmonary arterial catheterization is a rare but life-threatening complication with a mortality rate of 50%. Preoperative identification of patients at risk and proper intraoperative catheter management can reduce the associated morbidity and mortality.
Non-Malignant Hyperthermia
Authors: Ferguson Kyle , Johnson Angela
Published: May 2024

Perioperative hyperthermia can have numerous etiologies which can prove detrimental to patient outcomes. Many causes of hyperthermia are secondary to iatrogenic administration of medications that lead to chemical imbalance of the thermoregulatory centers in the brain. Medications and pathologic states that affect the serotonergic, dopaminergic, adrenergic, and cholinergic systems can alter the thermoregulatory actions of the hypothalamus, resulting in systemic temperature dysregulation. Many of these disorders present in very similar manners. Hyperthermic states can be difficult to diagnose; however, they carry a high risk of morbidity and mortality, and quick recognition and treatment are crucial.
Laryngospasm
Authors: Beebe David S. , Belani Kumar G.
Published: May 2024

Laryngospasm is a complication that can happen to all patients undergoing anesthesia, but it is more common in infants and small children, patients with upper airway infections and those undergoing surgery in the mouth or larynx, and patients who are obese. Stimulation of the larynx can cause the vocal cords to close and prevent ventilation. This can occur both during induction of general anesthesia and upon emerging from anesthesia. Anesthesiologists must therefore always be prepared to open the airway, including using skeletal muscle relaxants if necessary to provide oxygenation, ventilation, and prevent the serious complications that may result from untreated laryngospasm.
Postobstructive Pulmonary Edema
Authors: Kloesel Benjamin , Horvath Balazs
Published: May 2024

Postobstructive pulmonary edema (POPE) can occur in the perioperative period. A variety of causes, including upper airway obstruction due to oropharyngeal anatomical and functional variations, oversedation, laryngospasm, and occlusion of the endotracheal tube, may result in supraglottic or glottic obstruction. Respiratory efforts against an obstructed airway can generate negative pleural pressures significantly below the physiological level. The large pressure gradient increases venous return to the heart and facilitates fluid movement from the alveolar capillary network into the alveoli. The ensuing pulmonary edema causes dyspnea, hypoxemia, and cough. POPE is frequently self-limited with good prognosis but, depending on the severity, may require treatment ranging from supplemental oxygen to mechanical ventilation and potentially even extracorporeal life support.
Agonist-Antagonists
Authors: Trehan Gaurav , Sethi Anish
Published: May 2024

The agonist-antagonist analgesics, unlike pure opioid agonists (e.g., morphine), were originally created to retain the potency of morphine without the respiratory side effects. The mechanism of action is primarily as an agonist at the kappa receptors and an antagonistic or partial agonist at the mu opioid receptors. These drugs exhibit a characteristic “ceiling effect” to respiratory depression as well as analgesia. This class of medications include nalorphine, pentazocine, butorphanol, nalbuphine, buprenorphine, bremazocine, dezocine, and meptazinol, among others. In recent years, buprenorphine has gained widespread acceptance for the treatment of chronic pain and opioid use disorder (OUD). The medical provider should be well acquainted with this unique and popular drug so as to appropriately manage patients in emergent as well as elective situations.
Postoperative Nausea and Vomiting
Authors: Swanson David E.
Published: May 2024

Postoperative nausea and vomiting (PONV) continue to be significant problems after surgery. Major advances in minimizing the related morbidity occurred with the realization that preoperative risk assessment, combined with multimodal management of both prophylaxis and analgesia, is key. Timely preoperative ordering of a scopolamine patch in high-risk patients and without contraindications, along with oral acetaminophen or other analgesics, is helpful. Intraoperative avoidance of nitrous oxide and volatile anesthetics by using a total intravenous anesthetic will also reduce PONV. Utilizing medications with different mechanisms of action will maximize efficacy while minimizing adverse effects for optimum patient satisfaction. This is true for both prophylaxis and treatment. In the recovery room, choosing a different class of medication for treatment than has already been used intraoperatively for prophylaxis is more likely to be effective.
Neurologic Consequences of Anesthesia
Authors: Latimer Dustin , Kaye Alan D.
Published: May 2024

Postoperative complications are multifactorial, with a significant percentage related to neurologic related pathophysiologic states. This chapter outlines a variety of neurologic-related conditions, including seizure, postoperative delirium, delayed emergence, serotonin syndrome, neuroleptic malignant syndrome, and malignant hyperthermia. This purpose of this chapter is to prevent premature consultations to neurology and prompt action for postoperative complications reversed by appropriate identification of pathology. As with most medical care, a thorough history and physical can minimize preventable complications, but rapid and accurate assessment of reversible pathology can lead to appropriate action and improved outcomes while minimizing excessive consultations and optimizing healthcare spending.
Subcortical Areas
Authors: Latimer Dustin , Kaye Alan D.
Published: May 2024

The subcortical region of the brain includes important structures such as the basal ganglia, hippocampus, internal capsule, cerebellum, brainstem, and reticular activating system. These structures are important in a variety of important functions related to human cognition and affective and social function between the periphery and the cerebral cortex. Disruption of the basal ganglia has been known to be responsible for movement disorders. Alzheimer’s has been associated with atrophied hippocampal region. The internal capsule functions to transmit information to and from the cerebral cortex. This chapter describes the function of subcortical regions of the brain in further detail.
Effects of Brain Trauma and Tumors
Authors: Latimer Dustin , Kaye Alan D.
Published: May 2024

Brain trauma and brain tumors often lead to surgical interventions. These interventions require capable anesthesia providers who appreciate anesthesia-related effects on neurophysiology. Delays in treatment of reversible pathology can have devastating consequences. This review highlights important features of brain trauma and brain tumors related to anesthesia considerations in perioperative management. Preventing traumatic brain injury reigns as the most crucial aspect of maintaining healthy brain substrate but being knowledgeable about the consequences of perioperative complications can spare millions of neurons and brain functionality. Blood pressure, intracranial pressure, and cerebral perfusion pressures are objective measures that will be discussed in this chapter.
Blood-Brain Barrier
Authors: Spence Allyson L. , Cornett Elyse M.
Published: May 2024

The blood-brain barrier is crucial for CNS regulation, neuronal functioning, and preventing harmful substances from entering the brain. Likewise, the transport of drugs into the brain is prevented by the blood-brain barrier, which has prompted the development of drugs that more readily cross the blood-brain barrier. General anesthetic agents can alter the function of the blood-brain barrier, which is important to consider in patients with neurological disorders. Blood-brain barrier disruption can be assessed and diagnosed using a cerebrospinal fluid/plasma albumin ratio. More studies are warranted to assess the effects of anesthetic agents on the blood-brain barrier, but there is evidence to suggest that isoflurane, fentanyl, ketamine, and pentobarbital can increase blood-brain barrier permeability.
Spinal Cord Morphology
Authors: Woodrow Alex , Sharma Archit
Published: May 2024

The spinal cord is a cylindrical extension of the central nervous system that is contained within the bony spinal canal. White matter contains the axons of the ascending (sensory) and descending (motor) pathways, while the gray matter consists of the dorsal (sensory) and ventral (motor) horn and contains the cell bodies that synapse with sensory and motor neurons. Vascular supply is largely provided by branches of the aorta, subclavian artery, and internal iliac arteries. Understanding the morphology and intraoperative monitoring using evoked potentials is paramount to reduce complications after major spinal and neurological procedures. This chapter reviews the spinal cord anatomy, blood supply, and course of these tracts, and describes the various associated syndromes.
Sex, Gender, and Age Differences in Pain and Pain Perception
Authors: Rushmer Timothy , Abd-Elsayed Alaa
Published: May 2024

The International Association for the Study of Pain (IASP) defines pain as “[a]n unpleasant sensory and emotional experience associated with, or resembling that associated with, actual or potential tissue damage.” This definition intentionally leaves space for pain and pain perception to be influenced by a variety of objective and subjective inputs. As this chapter discusses, sex, gender, and age certainly have biological as well as psychosocial impacts on pain and pain perception.
Parasympathetic Nervous System
Authors: Lucas Tanya
Published: May 2024

The parasympathetic nervous system (PSNS) and the sympathetic nervous system (SNS) make up the motor system for the viscera. These systems modulate the activity of the organs, and together they are known as the autonomic nervous system. The PSNS dominates during periods of energy conservation (rest and digest). The PSNS has a more specific effect on individual organs than the SNS, as the ganglia of the two-neuron system are found near or within the organs controlled. Acetylcholine is the neurotransmitter found in both the preganglionic and postganglionic nerve of the PSNS.
Autonomic Reflexes
Authors: Strand Natalie H. , Maloney Jillian A.
Published: May 2024

The autonomic nervous system is divided into the parasympathetic and sympathetic nervous system. The autonomic nervous system targets smooth muscle to exert its effect on heart rate, respiratory rate, gastrointestinal function, urination, and gland activity. Autonomic reflexes are involuntary and are a result of an autonomic reflex arc which consists of a receptor, sensory neuron, integrating center, and both a preganglionic and postganglionic motor neuron. Disease states that disrupt the autonomic nervous system have several anesthetic implications to consider. Preoperative bowel care and voiding prior to surgery reduces the risk of bladder or bowel distension intraoperatively. Aggressive blood pressure management intraoperatively and removing the noxious stimuli is recommended.
Cerebellum and Basal Ganglia
Authors: Kaye Alan D. , Possoit Harlee
Published: May 2024

The cerebellum and basal ganglia are key structures of the central nervous system. These structures are important in a variety of functions, such as human cognition and coordination, which relay information to and from the cerebral cortex and periphery. Dysfunction of the cerebellum and basal ganglia can lead to dysfunction of balance and smooth coordinated movements. This chapter summarizes the anatomy, function, pathways, and key pathologies of the cerebellum and basal ganglia.
Reticular Activating System
Authors: Shah Rutvij
Published: May 2024

The reticular formation is made up of a loose group of neurons extended from the cervical cord caudally to the thalamus rostrally. The ascending pathway of reticular formation, also known as ascending reticular activating system (RAS), is responsible for arousal of a person and modulation of nociception. RAS constitutes several nuclei that has serotonergic, noradrenergic, cholinergic, glutaminergic, and histaminergic neurotransmitters. Disturbance to RAS results in sleep disturbances, schizophrenia, altered pain perception, post-traumatic stress disorder, and Parkinson’s disease. The synthetic opioid fentanyl controls the pain and reduces arousals by decreasing acetylcholine in the medial pontine reticular formation. The rapid atonia by a bolus dose of propofol is due to the drug’s effects on these reticular nuclei and GABAergic neurons of the spinal cord.
Sacral Nerves
Authors: Topfer Jacob , Abdallah Rany T.
Published: May 2024

The sacrum is a large structure that is made up of 5 sacral vertebrae. The 5 sacral nerves run within the sacrum and are part of the lumbosacral plexus. These sacral nerves exit the sacrum through their intervertebral foramina and provide sensory and motor function to portions of the lower extremity and perineum. The sacral plexus is formed with the union of the lumbosacral trunk from L4 to S4 and gives rise to 12 peripheral nerves, including the sciatic nerve, pudendal nerve, and posterior femoral cutaneous nerves of the thigh. Additionally, there is parasympathetic nervous system output from S2 to S4 nerves that supply the colon, rectum, uterus, and bladder. The sacral nerves and lumbosacral plexus are extremely important for lower extremity function, but also as an etiology and source of pain in that area. Peripheral nerve blocks and spinal cord stimulation techniques are utilized to help control pain coming from the sacral nerves.
Cranial Nerves
Authors: George Arun , Rajan Shobana
Published: May 2024

Cranial nerves transmit information including senses of vision, smell, hearing, and taste. There are 12 cranial nerves; the olfactory and optic nerves arise from the cerebrum, while the other 10 arise from the brainstem. Cranial nerves are generally named according to their structure or function. They are numbered based on their position from front to back (rostral to caudal) of their position on the brainstem. The 12 cranial nerves were characterized by some of history’s most famous anatomists from Galen to Von Sommering. Understanding cranial nerve anatomy and function is important for anesthesiologists as there are many physiological and perioperative considerations.
Ascending Pathways and Descending Inhibition
Authors: Lennertz Richard
Published: May 2024

Most nociceptors carry pain signals from the body and synapse in the dorsal horn of the spinal cord. Pain signals from the body cross midline in the spinal cord and ascend along tracts in the contralateral spinal cord. The spinothalamic tract is the dominant pathway for discriminatory pain and projects to the somatosensory cortex. The spinobulbar tract is the dominant pathway for affective pain and projects to multiple cortical areas. Nociceptors from the face and vagal afferents project to sensory nuclei in the brainstem. Descending output from the rostral ventromedial medulla and locus coeruleus modulate nociceptive processing in the dorsal horn.