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Surgery_Schwartz. SR, Fan KL, Scott AM, Gamble L, Baker SB. Assessing patient-reported satisfaction with appearance and quality of life following rhinoplasty using the FACE-Q appraisal scales. Plast Reconstr Surg. 2015;135(5):830e-837e. 71. Papadopulos NA, Niehaus R, Keller E, et al. The psychologic and psychosocial impact of otoplasty on children and adults. J Craniofac Surg. 2015;26(8):2309-2314. 72. McGrath MH. The psychological safety of breast implant sur-gery. Plast Reconstr Surg. 2007;120(7 suppl 1):103S-109S. 73. Papadopulos NA, Staffler V, Mirceva V, et al. Does abdomino-plasty have a positive influence on quality of life, self-esteem, and emotional stability? Plast Reconstr Surg. 2012;129(6):957e-962e. 74. Shridharani SM, Magarakis M, Manson PN, Rodriguez ED. Psychology of plastic and reconstructive surgery: a systematic clinical review. Plast Reconstr Surg. 2010;126(6):2243-2251. 75. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 5th ed. Arlington,


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Surgery_Schwartz. surgery: a systematic clinical review. Plast Reconstr Surg. 2010;126(6):2243-2251. 75. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders. 5th ed. Arlington, VA: American Psychiatric Association; 2013.Brunicardi_Ch45_p1967-p2026.indd 202601/03/19 6:32 PM


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Surgery_Schwartz. Anesthesia for Surgical PatientsJunaid Nizamuddin and Michael O’Connor 46chapterBRIEF HISTORY OF ANESTHESIAThe discovery of anesthesia is one of the seminal American con-tributions to the world. Along with infection control and blood transfusion, anesthesia has enabled surgery to occupy its fundamental place in medicine. Before the advent of anes-thesia in the 1840s, many substances and methods had been tried in the search for pain relief and better operating conditions. Patients were typically restrained by several attendants, and only the most stoic could tolerate the screams heard in the oper-ating theater.BeginningsHorace Wells (1815–1848), a dentist, first pursued using nitrous oxide for the relief of pain in surgical procedures in 1844.1 After experimenting on himself, Wells attempted to demonstrate the analgesic effects of nitrous oxide for a dental procedure at Harvard Medical School in 1845. The public demonstration was a failure, at least partially, due to improper


Surgery_Schwartz

Surgery_Schwartz. attempted to demonstrate the analgesic effects of nitrous oxide for a dental procedure at Harvard Medical School in 1845. The public demonstration was a failure, at least partially, due to improper administration of the gas. Wells never recovered from his humiliating experience and eventually committed suicide. However, he does hold a place in history as the first person to recognize and use the only anesthetic from the 1800s that is still in use today—nitrous oxide.Ether DayWilliam Morton (1819–1868) was a dentist and partner of Horace Wells. After taking a course in anesthesia from Wells, Morton left the partnership in Hartford, Connecticut, and established himself in Boston. He continued his interest in anesthesia, but using diethyl ether instead of nitrous oxide. Ether proved a good choice. He practiced the administration of ether on a 11dog and then used it when extracting teeth from patients in his office. On October 16, 1846, Morton gave the first pub-lic demonstration of ether


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Surgery_Schwartz. He practiced the administration of ether on a 11dog and then used it when extracting teeth from patients in his office. On October 16, 1846, Morton gave the first pub-lic demonstration of ether as an anesthetic for Johns Collins Warren, a distinguished surgeon and one of the founders of Massachusetts General Hospital. In attendance in the surgi-cal amphitheater were several surgeons, medical students, and a newspaper reporter. After induction of anesthesia, Warren successfully removed a vascular mass from the patient’s neck with no ill effects (Fig. 46-1). The description of this public demonstration of ether was published in the Boston Medical and Surgical Journal (now The New England Journal of Medicine).2 The stature of Warren lent considerable credence to the advent of surgical anesthesia. The news spread rapidly, and surgeons around the world were quick to adopt this new invention. Massachusetts General Hospital has restored and preserved the original amphi-theater where the


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Surgery_Schwartz. The news spread rapidly, and surgeons around the world were quick to adopt this new invention. Massachusetts General Hospital has restored and preserved the original amphi-theater where the demonstration took place, now called the Ether Dome. The description of the public demonstration of ether was voted as the most important article published in the history of The New England Journal of Medicine in its first 200 years.3The Modern EraAnesthesia has developed rapidly over the past century. Inhaled anesthetics, initially discovered fortuitously by observation, have been synthetically produced and remain the mainstay of anesthetic maintenance. The advent of the hollow syringe and needle and discovery of rapidly acting of intravenous anesthet-ics allowed for rapid induction of anesthesia. Development of endotracheal intubation and mechanical ventilation revolution-ized the delivery of inhaled anesthetics. The discovery of local anesthetics led to the development of peripheral nerve blocks


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Surgery_Schwartz. of endotracheal intubation and mechanical ventilation revolution-ized the delivery of inhaled anesthetics. The discovery of local anesthetics led to the development of peripheral nerve blocks Brief History of Anesthesia 2027Beginnings / 2027Ether Day / 2027The Modern Era / 2027Basic Pharmacology 2028Pharmacokinetics and Pharmacodynamics / 2028Administration, Distribution, Metabolism, and Elimination / 2029Pharmacodynamics / 2029Potency, Efficacy, Lethal Dose, and Therapeutic Index / 2029Anesthetic Agents 2029Inhaled Anesthetics / 2029Local Anesthetics / 2031Neuromuscular Blockers / 2031Anesthetic Monitoring 2032Perioperative Evaluation and Preparation 2033ASA Physical Status Assessment / 2034Airway Evaluation / 2034Cardiovascular Disease / 2034Pulmonary Disease / 2035Renal Disease / 2036Hepatic Disease / 2036Endocrine Disease / 2036Preoperative Fasting / 2036Patients With Advanced Directives / 2036Risk Estimation / 2036Intraoperative Management 2036General Anesthesia /


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Surgery_Schwartz. / 2036Hepatic Disease / 2036Endocrine Disease / 2036Preoperative Fasting / 2036Patients With Advanced Directives / 2036Risk Estimation / 2036Intraoperative Management 2036General Anesthesia / 2036Monitored Anesthesia Care / 2039Regional Anesthesia/Acute Pain / 2039Recovery And Complications 2039The Postanesthesia Care Unit / 2039Enhanced Recovery After Surgery Pathways / 2039Acute Postoperative Pain / 2039Malignant Hyperthermia / 2040Cardiovascular Complications / 2040Respiratory Failure / 2040Neurologic and Psychiatric Complications / 2040Conclusion 2040Brunicardi_Ch46_p2027-p2044.indd 202701/03/19 11:03 AM 2028Figure 46-1. Robert Cutler Hinckley, The First Operation with Ether. (Reproduced with permission from Boston Medical Library in the Francis A. Countway Library of Medicine, Boston, Massachusetts.)Key Points1 The discovery of anesthesia was one of the most important advances and has enabled surgery to occupy its fundamental place in medicine.2 Advances in anesthetic


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Surgery_Schwartz. Boston, Massachusetts.)Key Points1 The discovery of anesthesia was one of the most important advances and has enabled surgery to occupy its fundamental place in medicine.2 Advances in anesthetic monitoring have made the admin-istration of anesthesia safer than ever. Types of cardiovas-cular monitors include arterial catheters, central venous and pulmonary artery catheters, and transesophageal echocardiography.3 A detailed preoperative evaluation should be performed on each patient when circumstances allow, with special atten-tion devoted to functional status. The American College of Cardiology/American Heart Association guidelines for pre-operative evaluation can guide workup.4 The American Society of Anesthesiologists has developed specific guidelines for preoperative fasting to mitigate the risk of aspiration of gastric contents; individual patients may need more stringent preoperative fasting periods and/or rapid sequence inductions.5 The American Society of Anesthesiologists has


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Surgery_Schwartz. the risk of aspiration of gastric contents; individual patients may need more stringent preoperative fasting periods and/or rapid sequence inductions.5 The American Society of Anesthesiologists has developed an algorithm for management of the difficult airway. Nota-bly, in patients in whom both intubation and ventilation are impossible, the algorithm calls for placement of a laryngeal mask airway as the next step.and spinal anesthesia. Concurrently, physiologic monitoring techniques have advanced to make the administration of anes-thesia safer than ever.Initially, anesthesia was given by medical students, nurses, and dentists, but eventually became a physician specialty of medicine of its own. The American Board of Anesthesiology was formed in 1938. Over the past 50 years, anesthesiology has increasingly specialized and also spread outside the operating room into critical care, pain management, and perioperative medicine.BASIC PHARMACOLOGYPharmacokinetics and


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Surgery_Schwartz. 50 years, anesthesiology has increasingly specialized and also spread outside the operating room into critical care, pain management, and perioperative medicine.BASIC PHARMACOLOGYPharmacokinetics and PharmacodynamicsPharmacodynamics is the study of what a drug does to the body; pharmacokinetics is the study of what the body does to a drug. Brunicardi_Ch46_p2027-p2044.indd 202801/03/19 11:04 AM 2029ANESTHESIA FOR SURGICAL PATIENTSCHAPTER 46The conduct of anesthesia is predicated upon the pharmacody-namics and pharmacokinetics of the drugs used.4Administration, Distribution, Metabolism, and EliminationAdministration of a drug affects its pharmacokinetics, as there will be different rates of drug entry into the circulation. For example, medications administered via the oral route are subject to first-pass effect of the portal circulation; this can be bypassed with the IV, nasal, or sublingual route. Other routes of drug administration include transdermal, intramuscular, subcutaneous,


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Surgery_Schwartz. to first-pass effect of the portal circulation; this can be bypassed with the IV, nasal, or sublingual route. Other routes of drug administration include transdermal, intramuscular, subcutaneous, or inhalation.Distribution is the delivery of a drug from the systemic circulation to the tissues. Once a drug has entered the systemic circulation, the rate at which it will enter the tissues depends on the blood flow into that tissue, as well as the molecular size of the drug, lipid solubility, capillary permeability, polarity, plasma protein and tissue binding, and volume of distribution, the fluid volume in which the drug distributes. The distribution or redis-tribution of drugs can play a critical role in shaping their clinical use. For instance, clinically, the effect of propofol is terminated by its redistribution into fatty tissues and not metabolism of the drug.Metabolism is the permanent breakdown of original compounds into smaller metabolites. Drug elimination varies widely; some


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Surgery_Schwartz. by its redistribution into fatty tissues and not metabolism of the drug.Metabolism is the permanent breakdown of original compounds into smaller metabolites. Drug elimination varies widely; some drugs are excreted unchanged by the body, some decompose via plasma enzymes, and some are degraded in the liver. Many drugs rely on multiple pathways for metabolism and elimination (i.e., metabolized by liver enzymes and then excreted by the kidney).Context-sensitive half time is the time required for blood concentrations of a drug to decrease by 50% after its discontinu-ation, which is determined by the interaction of the duration of administration, distribution and accumulation, and metabolism and excretion. Fig. 46-2 illustrates the context sensitive half-time for commonly used anesthetics and opioids.4PharmacodynamicsPharmacodynamics, or how the plasma concentration of a drug translates into its effect on the body, depends on biologic vari-ability, receptor physiology, and clinical


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Surgery_Schwartz. and opioids.4PharmacodynamicsPharmacodynamics, or how the plasma concentration of a drug translates into its effect on the body, depends on biologic vari-ability, receptor physiology, and clinical evaluations of the actual drug. An agonist is a drug that causes a response (acti-vates a receptor). A full agonist produces the full receptor/tissue response, and a partial agonist elicits less than the maximum response induced by a full agonist. An antagonist is a drug that blocks agonist mediated responses. An additive effect means that a second drug acts with the first drug and will produce an effect that is equal to the algebraic summation of both drugs. A synergistic effect means that two drugs interact to produce an effect that is greater than expected from the two drugs’ alge-braic summation. Tolerance, desensitization, or tachyphylaxis occurs when a larger than expected dose is required to produce a response. Tolerance usually results from chronic drug exposure, either through


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Surgery_Schwartz. summation. Tolerance, desensitization, or tachyphylaxis occurs when a larger than expected dose is required to produce a response. Tolerance usually results from chronic drug exposure, either through enzyme induction (e.g., alcohol) or depletion of neurotransmitters (e.g., cocaine).4Potency, Efficacy, Lethal Dose, and Therapeutic IndexThe potency of a drug is the dose required to produce a given effect, such as pain relief or a change in heart rate. The aver-age sensitivity to a particular drug can be expressed through the calculation of the effective dose; ED50 would have the desired effect in 50% of the general population. The efficacy of any therapeutic agent is its power to produce a desired effect. Two drugs may have the same efficacy but different potencies. Dose-response curves show the relationship between the dose of a drug administered (or the resulting plasma concentration) and the pharmacologic effect of the drug. The lethal dose (LD50) of a drug produces death in 50% of


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Surgery_Schwartz. the relationship between the dose of a drug administered (or the resulting plasma concentration) and the pharmacologic effect of the drug. The lethal dose (LD50) of a drug produces death in 50% of animals to which it is given, and the toxic dose (TD50) is the dose that elicits a toxicity in 50% of humans to which it is given. The ratio of the toxic dose and effective dose, TD50/ED50, is the therapeutic index. A drug with a high therapeutic index is safer than a drug with a low or narrow therapeutic index.4ANESTHETIC AGENTSInhaled AnestheticsInhaled anesthetics have greatly advanced since the original dem-onstration with ether. Modern agents provide faster induction and emergence and provide all of the major characteristics of general anesthesia: unconsciousness, analgesia, and muscle relaxation.Minimum alveolar concentration (MAC) is a measure of anesthetic potency. It is the ED50 of an inhaled agent (i.e., the dose required to prevent movement in response to skin incision in 50% of


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Surgery_Schwartz. alveolar concentration (MAC) is a measure of anesthetic potency. It is the ED50 of an inhaled agent (i.e., the dose required to prevent movement in response to skin incision in 50% of patients). The higher the MAC, the less potent an agent is. Advantages and disadvantages of inhaled anesthetics are shown in Table 46-1.5Nitrous Oxide. Nitrous oxide has a low solubility and is a weak anesthetic agent, but it has the most rapid onset and offset. Because 600500400300Duration of infusion (min)2001000020406080100120140Time required for plasmalevels to drop by 50% (min)AEtomidateMidazolamPropofolSufentanilFentanylRemifentanil600500400300Duration of infusion (min)2001000020406080100120140Time required for plasmalevels to drop by 50% (min)BFigure 46-2. Context-sensitive half time for commonly used anesthetics (A) and opioids (B). The vertical axis represents the half-time, or the time required for plasma concentrations of the drug to drop by 50%. The horizontal axis represents the duration of


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Surgery_Schwartz. anesthetics (A) and opioids (B). The vertical axis represents the half-time, or the time required for plasma concentrations of the drug to drop by 50%. The horizontal axis represents the duration of a continuous infusion. (Reproduced with permission from Longnecker DE, Mackey SC, Newman MF, et al: Anesthesiology, 3rd ed. New York, NY: McGraw-Hill Education; 2018.)Brunicardi_Ch46_p2027-p2044.indd 202901/03/19 11:04 AM 2030SPECIFIC CONSIDERATIONSPART IITable 46-1Advantages and disadvantages of inhaled anestheticsANESTHETICADVANTAGESDISADVANTAGESNitrous OxideNo odor, taste, or pungencyRapid uptake and eliminationAnalgesic effectMinimal cardiovascular depressionMinimal biotransformationInexpensiveAirspace expansionIncreased nausea and vomitingInhibits methionine synthaseEnvironmental pollutantSupports combustionIsofluraneGood muscle relaxationBronchodilationStable heart rateInexpensiveSlow uptake and eliminationSevoflurane Rapid uptake and eliminationNot pungentBreakdown to compound A


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Surgery_Schwartz. combustionIsofluraneGood muscle relaxationBronchodilationStable heart rateInexpensiveSlow uptake and eliminationSevoflurane Rapid uptake and eliminationNot pungentBreakdown to compound A in circuitMore expensive than isofluraneDesflurane Rapid uptake and eliminationVery low biotransformationAirway irritantRequires electric/heated vaporizerExpensiveData from Longnecker DE, Brown DL, Newman MF, et al: Anesthesiology, 2nd ed. New York, NY: McGraw-Hill Ediucation; 2012.its MAC is 104%, it must be combined with other agents to pro-vide general anesthesia. A recent randomized controlled trial demonstrated that use of 70% nitrous oxide, given as part of a general anesthetic, did not increase the risk of death or major adverse cardiovascular events.6 Nitrous oxide has been shown to increase the rate of postoperative nausea and vomiting (PONV).Volatile Agents. The volatile inhaled anesthetics are gener-ally more soluble in blood than nitrous oxide, are more potent, and thus require lower


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Surgery_Schwartz. the rate of postoperative nausea and vomiting (PONV).Volatile Agents. The volatile inhaled anesthetics are gener-ally more soluble in blood than nitrous oxide, are more potent, and thus require lower inspired concentrations. Currently, iso-flurane, sevoflurane, and desflurane are the agents that are most commonly used. Older agents, including halothane, which was associated with hepatotoxicity, are no longer widely used.Isoflurane is the most inexpensive and widely available of the agents currently used. Sevoflurane has relatively rapid uptake and elimination. It is also not pungent and is therefore commonly used for inhalational induction. Desflurane has the most rapid uptake and elimination of the three most commonly used volatile agents. It is also the most expensive, requires a heated-electric vaporizer, and is an airway irritant. All of the volatile inhalational agents as well as the depolarizing neu-romuscular blocker succinylcholine are triggering agents for malignant


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Surgery_Schwartz. a heated-electric vaporizer, and is an airway irritant. All of the volatile inhalational agents as well as the depolarizing neu-romuscular blocker succinylcholine are triggering agents for malignant hyperthermia.5Intravenous Agents. Intravenous agents are used to produce unconsciousness, analgesia, muscle relaxation, and/or amnesia. They include barbiturates, propofol, benzodiazepines, ketamine, etomidate, opioids, and nonopioid analgesics.7Barbiturates Barbiturates used in anesthesia include thio-pental and methohexital. These drugs act as agonists at the γ-aminobutyric acid (GABA) receptor, which inhibit excitatory synaptic transmission. Clinically, they produce a rapid, smooth induction of general anesthesia and wear off quickly. They cause hypotension and myocardial depression in a dose-dependent manner. Barbiturates are seldom used in modern anesthesia, with the exception of methohexital, which is still commonly used dur-ing electroconvulsive therapy.Propofol Propofol is an


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Surgery_Schwartz. a dose-dependent manner. Barbiturates are seldom used in modern anesthesia, with the exception of methohexital, which is still commonly used dur-ing electroconvulsive therapy.Propofol Propofol is an alkylated phenol that inhibits synaptic transmission through its effects at the GABA receptor. It has a short duration, rapid recovery, and low incidence of nausea and vomiting. Consequently, it is the induction agent of choice. Propofol causes hypotension in a dose-dependent manner, and it should be used cautiously in patients with cardiac disease or hypovolemia. Continuous infusion of propofol is commonly used for sedation in the intensive care unit setting. Continuous infusions of propofol are also used for moderate-to-deep seda-tion for many procedures and are also commonly incorporated into total intravenous anesthetics (TIVA), most commonly for neurosurgical procedures. Propofol is an irritant and frequently causes pain on injection. Propofol also has anticonvulsant


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Surgery_Schwartz. incorporated into total intravenous anesthetics (TIVA), most commonly for neurosurgical procedures. Propofol is an irritant and frequently causes pain on injection. Propofol also has anticonvulsant properties.Benzodiazepines Benzodiazepines are most commonly used to reduce anxiety and produce amnesia. Midazolam, which has a rapid onset and relatively short duration of action, is by far the most commonly used benzodiazepine in anesthesia. Lorazepam and diazepam are still sometimes used as anxiolytics or amnes-tics. Benzodiazepines act as agonists at the GABAA receptor. They produce sedation, vasodilation, and respiratory depres-sion in a dose-dependent manner. They should be used with caution when given with opioids because a synergistic reaction causing respiratory depression is common. Oral midazolam is commonly used for anxiolysis in children. Benzodiazepines are excellent anticonvulsants and only rarely cause allergic reac-tions. Benzodiazepines should be administered cautiously in


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Surgery_Schwartz. midazolam is commonly used for anxiolysis in children. Benzodiazepines are excellent anticonvulsants and only rarely cause allergic reac-tions. Benzodiazepines should be administered cautiously in older adult patients due to the heightened risk of delayed awak-ening and postoperative delirium.Etomidate Etomidate is an imidazole derivative used for IV induction. Its rapid and almost complete hydrolysis to inactive metabolites results in rapid offset. Like the IV agents mentioned earlier, etomidate acts on the GABA receptor. Etomidate has little direct effect on cardiac output and heart rate; induction doses thus cause less reduction in blood pressure than seen with propofol. Etomidate is associated with pain on injection. Nota-bly, etomidate causes adrenal suppression,8,9 although whether a single dose of etomidate given at induction causes clinically relevant adrenal suppression remains controversial.10-13Dexmedetomidine Dexmedetomidine is an IV α2-adrenergic agonist, administered as


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Surgery_Schwartz. a single dose of etomidate given at induction causes clinically relevant adrenal suppression remains controversial.10-13Dexmedetomidine Dexmedetomidine is an IV α2-adrenergic agonist, administered as a continuous infusion, and has both sedative and analgesic properties. It is useful for sedation in an intensive care unit setting and as an adjunct to general anes-thesia, especially as part of a total intravenous anesthetic. Side effects include hypotension and bradycardia in a dose-dependent manner. It does not cause respiratory depression at commonly used doses and is thus particularly useful for procedural seda-tion for patients at high risk of respiratory complications. It is synergistic with opiates and thus can be used to facilitate an opiate-sparing anesthetic.14,15Ketamine Ketamine differs from the aforementioned IV agents in that it produces analgesia as well as amnesia. Its principal Brunicardi_Ch46_p2027-p2044.indd 203001/03/19 11:04 AM 2031ANESTHESIA FOR SURGICAL


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Surgery_Schwartz. differs from the aforementioned IV agents in that it produces analgesia as well as amnesia. Its principal Brunicardi_Ch46_p2027-p2044.indd 203001/03/19 11:04 AM 2031ANESTHESIA FOR SURGICAL PATIENTSCHAPTER 46action is on the N-methyl-d-aspartate (NMDA) receptor. It is a dissociative anesthetic, producing a cataleptic gaze with nystag-mus. Patients may experience delirium and hallucinations while regaining consciousness. The addition of benzodiazepines has been shown to reduce the incidence of these side effects. Ket-amine typically increases heart rate and blood pressure, which may cause myocardial ischemia in patients with coronary dis-ease. Ketamine is often used in acutely hypovolemic patients to maintain blood pressure via sympathetic stimulation. Impor-tantly, ketamine is a direct myocardial depressant in patients who are catecholamine depleted, and it can produce profound hypotension and low cardiac output in such patients. Ketamine is a bronchodilator and is sometimes used


Surgery_Schwartz

Surgery_Schwartz. myocardial depressant in patients who are catecholamine depleted, and it can produce profound hypotension and low cardiac output in such patients. Ketamine is a bronchodilator and is sometimes used as an induction agent in asthmatic patients. It can increase intracranial pressure and intraocular pressure, and thus its use in patients with trauma to the head and neck is controversial. Ketamine can be admin-istered intramuscularly to induce anesthesia in patients who would not tolerate an inhalational induction or IV placement, such as patients with developmental delay.Opioid Analgesics The commonly used opioids—morphine, codeine, hydromorphone, meperidine, and the fentanyl-based compounds—act on µ-receptors in the brain and spinal cord. The main side effects of opioids are euphoria, sedation, con-stipation, and respiratory depression, which also are mediated by µ-receptors in a dose-dependent fashion. Although opioids have differing potencies required for effective analgesia,


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Surgery_Schwartz. sedation, con-stipation, and respiratory depression, which also are mediated by µ-receptors in a dose-dependent fashion. Although opioids have differing potencies required for effective analgesia, equi-analgesic doses of opioids result in equal degrees of respiratory depression. Thus, there is no completely safe opioid analgesic, and no reason to suppose that one opioid is safer than another. The synthetic opioid fentanyl and its analogues sufentanil, alfentanil, and remifentanil are used in the operating room. They differ pharmacokinetically in their lipid solubility, tissue binding, and elimination profiles and thus have differing poten-cies and durations of action. Fentanyl, which is highly lipid-soluble, accumulates in tissues and exhibits a steep increase in its context-sensitive half-time with infusions. Remifentanil is remarkable in that it undergoes rapid hydrolysis that is unaf-fected by sex, age, weight, or renal or hepatic function, even after prolonged infusion. Alfentanil


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Surgery_Schwartz. with infusions. Remifentanil is remarkable in that it undergoes rapid hydrolysis that is unaf-fected by sex, age, weight, or renal or hepatic function, even after prolonged infusion. Alfentanil and sufentanil are seldom used, having largely been replaced by remifentanil in the mod-ern era. Morphine and meperidine have active metabolites that are renally excreted and thus should be used with caution or avoided in patients with renal insufficiency.Naloxone, an opioid antagonist, can be used to rapidly reverse the effects of opioids, and is commonly used to rescue patients from opioid-associated respiratory depression. Nalox-one is poorly absorbed orally and is also often combined with oral opioids to prevent abuse by injection use of the combined drug. Methylnaltrexone and alvimopan are both peripheral opi-oid antagonists and can reverse the opioid side effect of consti-pation without affecting analgesia.16,17Nonopioid Analgesics Ketorolac is a parenteral nonsteroidal anti-inflammatory


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Surgery_Schwartz. peripheral opi-oid antagonists and can reverse the opioid side effect of consti-pation without affecting analgesia.16,17Nonopioid Analgesics Ketorolac is a parenteral nonsteroidal anti-inflammatory drug (NSAID) that produces analgesia by reducing prostaglandin formation via inhibition of the enzyme cyclooxygenase (COX). Intraoperative use of ketorolac reduces postoperative need for opioids. Ketorolac along with other NSAIDs can cause major side effects, including bleeding, plate-let dysfunction, and acute kidney injury and should be used cau-tiously in elderly patients or patients with renal insufficiency.Acetaminophen is an analgesic drug and antipyretic; its site of action is in the central nervous system. Use of acetaminophen has been shown to reduce opioid requirements postoperatively. Long available in an orally administered form as well as a rec-tal suppository, an intravenous formulation of acetaminophen is now available which has become widely used in the postopera-tive


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Surgery_Schwartz. Long available in an orally administered form as well as a rec-tal suppository, an intravenous formulation of acetaminophen is now available which has become widely used in the postopera-tive setting.18Lidocaine is a local anesthetic commonly used for local infiltration, nerve blocks, or epidural infusions. Recently, intra-venous infusions of lidocaine have been shown to be beneficial in the perioperative period. A large meta-analysis of 42 trials with 2800 patients showed that intravenous lidocaine infusions modestly reduced postoperative pain, reduced opioid require-ments, and shortened time to recovery of bowel function for patients undergoing abdominal surgery.19Local AnestheticsLocal anesthetics act on sodium channels to block transmission of neural impulses. They are divided into two groups based on their chemical structure: the amides and the esters. In general, the amides are metabolized in the liver, and the esters are metabo-lized by plasma cholinesterases, which yield


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Surgery_Schwartz. two groups based on their chemical structure: the amides and the esters. In general, the amides are metabolized in the liver, and the esters are metabo-lized by plasma cholinesterases, which yield metabolites with slightly higher allergic potential than the amides. Amides include lidocaine, bupivacaine, mepivicaine, prilocaine, and ropivicaine. Lidocaine has a fairly rapid onset and is shorter acting. Ropivic-aine and bupivacaine have a slower onset and are longer lasting. All three are commonly used for local infiltration and regional nerve blocks. Amides are 95% metabolized in the liver, with a minority excreted unchanged in the kidneys. Prilocaine and mepivicaine are seldom used in anesthesia at present. Esters include cocaine, procaine, chloroprocaine, tetracaine, and ben-zocaine. Esters are hydrolyzed in the blood by plasma esterases.When used in large quantities over a short period of time, local anesthetic levels can rise in the blood and cause central nervous system (CNS)


Surgery_Schwartz

Surgery_Schwartz. Esters are hydrolyzed in the blood by plasma esterases.When used in large quantities over a short period of time, local anesthetic levels can rise in the blood and cause central nervous system (CNS) toxicity and cardiovascular toxicity. Symptoms of CNS toxicity include restlessness, tinnitus, and slurred speech and can progress to seizures and coma. Car-diovascular toxicity may manifest as hypotension, conduction abnormalities leading to heart block, and ventricular arrhyth-mias, and it may lead to cardiac arrest. The type of local anes-thetic used affects the risk of developing toxicity; bupivicaine is most often associated with cardiovascular toxicity. Other risk factors for local anesthetic systemic toxicity include cumulative dose, site of injection, and preexisting renal, hepatic, or cardiac disease in the patient.20 In addition to treating symptomatology, local anesthetic systemic toxicity can be treated with intrave-nous administration of lipid emulsion.21Neuromuscular


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Surgery_Schwartz. or cardiac disease in the patient.20 In addition to treating symptomatology, local anesthetic systemic toxicity can be treated with intrave-nous administration of lipid emulsion.21Neuromuscular BlockersWhile general anesthetics provide muscle relaxation, they usu-ally do so at a much deeper anesthetic depth than required for amnesia and hypnosis. For this reason, neuromuscular blockers are commonly administered to attain adequate relaxation at lev-els of anesthesia sufficient to produce hypnosis, amnesia, and analgesia. Neuromuscular blockers block conduction at the neu-romuscular junction of skeletal muscle.22The two categories of neuromuscular blockers in use are depolarizing and nondepolarizing blockers. Character-istics of neuromuscular blockers currently used are summa-rized in Table 46-2. Succinylcholine is the only depolarizing agent used currently. It binds to acetylcholine receptors on the postjunctional membrane in the neuromuscular junction and causes depolarization of


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Surgery_Schwartz. 46-2. Succinylcholine is the only depolarizing agent used currently. It binds to acetylcholine receptors on the postjunctional membrane in the neuromuscular junction and causes depolarization of muscle fibers. The rapid onset (less than 60 seconds) and rapid offset (5–8 minutes) of succinyl-choline make it ideal for management of the airway in certain Brunicardi_Ch46_p2027-p2044.indd 203101/03/19 11:04 AM 2032SPECIFIC CONSIDERATIONSPART IITable 46-2Commonly used neuromuscular blockersAGENTTYPEINTUBATING DOSECONSIDERATIONSSuccinylcholineDepolarizer1 mg/kgCan cause severe hyperkalemiaContraindicated in burns, denervating conditionsExcessive or prolonged use can lead to phase II blockRocuroniumNondepolarizer0.6 mg/kg1.2 mg/kg for RSIPrimarily hepatic metabolismCan be reversed with suggamadex or acetylcholinesterase inhibitorVecuroniumNondepolarizer0.1 mg/kgPrimarily hepatic metabolismCan be reversed with suggamadex or acetylcholinesterase inhibitorCisatracuriumNondepolarizer0.1


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Surgery_Schwartz. or acetylcholinesterase inhibitorVecuroniumNondepolarizer0.1 mg/kgPrimarily hepatic metabolismCan be reversed with suggamadex or acetylcholinesterase inhibitorCisatracuriumNondepolarizer0.1 mg/kgHoffman degradationCan be reversed with an acetylcholinesterase inhibitorRSI = rapid sequence inductionsituations.23 Succinylcholine has several adverse effects includ-ing transient hyperkalemia, which can be severe or even fatal for patients with burns and denervating injuries. Succinylcholine can cause bradycardia, which can be severe in children. It is also associated with transient increases in intracranial and intraocular pressure. The depolarization caused by succinylcholine causes skeletal muscles to fasciculate, which in turn, can result in post-operative myalgias. Succinylcholine is a known trigger of malig-nant hyperthermia in susceptible individuals. Succinylcholine is broken down by psuedocholinesterase; patients who are homo-zygous for pseudocholinestrase deficiency will have


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Surgery_Schwartz. known trigger of malig-nant hyperthermia in susceptible individuals. Succinylcholine is broken down by psuedocholinesterase; patients who are homo-zygous for pseudocholinestrase deficiency will have prolonged neuromuscular blockade, typically lasting for several hours.There are several nondepolarizing neuromuscular block-ing agents in clinical use. Long-acting agents including pan-curonium are no longer widely used. Intermediate-duration neuromuscular blockers include the steroid-based drugs vecuronium and rocuronium, which are metabolized by the liver as well as by the kidney, and the benzylisoquinolone drugs atra-curium and cisatracurium, which undergo breakdown in plasma known as Hofmann elimination. All nondepolarizers reversibly bind to the postsynaptic terminal in the neuromuscular junc-tion and prevent acetylcholine from depolarizing the muscle. Muscle blockade occurs without fasciculation and without the subsequent side effects seen with succinylcholine. Neuromus-cular


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Surgery_Schwartz. junc-tion and prevent acetylcholine from depolarizing the muscle. Muscle blockade occurs without fasciculation and without the subsequent side effects seen with succinylcholine. Neuromus-cular blockade with nondepolarizing drugs is typically reversed. Failure to adequately reverse neuromuscular blockade is associ-ated with an increased risk of perioperative respiratory failure and death. Reversal agents include acetylcholinesterase inhibi-tors including neostigmine, edrophonium, or pyridostigmine that are given concurrently with muscarinic-anticholinergics, almost always atropine or glycopyrrolate. Recently, suggama-dex, a chelating agent, has been approved for use as a reversal agent for reversal of neuromuscular blockade by the steroid paralytics rocuronium and vecuronium. When given at a very high dose, suggamadex can even rapidly reverse the effect of an intubating dose of a steroid neuromuscular blocker.ANESTHETIC MONITORINGOver the past several decades, advancement in anesthetic


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Surgery_Schwartz. a very high dose, suggamadex can even rapidly reverse the effect of an intubating dose of a steroid neuromuscular blocker.ANESTHETIC MONITORINGOver the past several decades, advancement in anesthetic moni-toring has made administration of anesthesia safer than ever. The goal of anesthetic monitoring is to continuously moni-tor the patients’ cardiovascular status, pulmonary status, respiratory physiology, anesthetic depth, concentration of gases administered, and temperature. The American Society of Anesthesiology (ASA) has established standards for basic intra-operative monitoring that are listed in Table 46-3. Types of anesthetic monitoring are listed in Table 46-4.Cardiovascular monitoring includes continuous ECG monitoring as well as blood pressure monitoring, which is to be measured and recorded at least every 5 minutes. Blood pressure monitoring can be done using noninvasive blood pressure cuff measurements or invasively using an arterial catheter. Other car-diovascular monitors


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Surgery_Schwartz. recorded at least every 5 minutes. Blood pressure monitoring can be done using noninvasive blood pressure cuff measurements or invasively using an arterial catheter. Other car-diovascular monitors include monitoring of central venous pres-sure, pulmonary artery pressure, and cardiac output. In high-risk 22Table 46-3American Society of Anesthesiologists standards for basic intraoperative monitoringStandardsStandard 1: Qualified anesthesia personnel shall be present in the room throughout the conduct of all general anesthetics and regional and monitored anesthesia care.Standard 2: Oxygenation, ventilation, circulation, and temperature shall be continually evaluated Oxygenation Inspired gas oxygen analyzer Pulse oximetry Monitoring of patient clinical status Ventilation Auscultation Observation of the patient Observation of reservoir bag End-tidal carbon dioxide analysis Circulation Continuous electrocardiogram display Heart rate and blood pressure recorded at least every 5


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Surgery_Schwartz. of the patient Observation of reservoir bag End-tidal carbon dioxide analysis Circulation Continuous electrocardiogram display Heart rate and blood pressure recorded at least every 5 minutes Evaluation of circulation: auscultation of heart sounds, palpation of pulse, pulse oximetry, blood pressure monitoring with noninvasive means or intra-arterial catheter pressure measurement Temperature Core and/or skin temperatureReproduced with permission from Longnecker DE, Mackey SC, Newman MF, et al: Anesthesiology, 3rd ed. New York, NY: McGraw-Hill Education; 2018.Brunicardi_Ch46_p2027-p2044.indd 203201/03/19 11:04 AM 2033ANESTHESIA FOR SURGICAL PATIENTSCHAPTER 46Table 46-4Types of anesthesia monitors and their propertiesTYPE OF MONITORWHAT IS MEASUREDINVASIVENESSPOTENTIAL FOR COMPLICATIONSPhysical examinationHeart sounds, breath sounds, pulse, color, mental status, etcNoninvasive–Pulse oximetryArterial oxygen saturationNoninvasive–Arterial catheterBlood pressure, acid/base


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Surgery_Schwartz. examinationHeart sounds, breath sounds, pulse, color, mental status, etcNoninvasive–Pulse oximetryArterial oxygen saturationNoninvasive–Arterial catheterBlood pressure, acid/base statusInvasive++Noninvasive blood pressure measurementBlood pressureNoninvasive+/–ElectrocardiographyCardiac rhythm, rate, ST segmentsNoninvasive–CapnographyVentilatory, circulatory statusNoninvasive–Electroenceophalogram, bispectral index, etcBrain function, depth of anesthesiaNoninvasive+/–Temperature probeBody temperatureNoninvasive to invasive+/–Central venous pressure, pulmonary artery pressureCardiac function, volume statusInvasive+++Transesophageal echocardiogramCardiac function, volume statusInvasive+++Adapted with permission from Longnecker DE, Mackey SC, Newman MF, et al: Anesthesiology, 3rd ed. New York, NY: McGraw-Hill Education; 2018.anesthetics such as liver transplantation and cardiac surgery, transesophageal echocardiography (TEE) is employed to moni-tor myocardial function and volume status.


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Surgery_Schwartz. NY: McGraw-Hill Education; 2018.anesthetics such as liver transplantation and cardiac surgery, transesophageal echocardiography (TEE) is employed to moni-tor myocardial function and volume status. Intraoperative TEE can also be used to guide surgeons when performing complex cardiac surgeries, including cardiac valve replacements.Monitoring of oxygenation and ventilation includes use of continuous pulse oximetry, monitoring of exhaled end-tidal carbon dioxide (ETCO2), and monitoring of fraction of inspired oxygen. End tidal CO2 monitoring also provides important infor-mation about systemic perfusion. During cardiac arrest, there is no delivery of CO2 to the lungs, and the end-tidal CO2 is thus very low or zero; a sudden spike in end tidal CO2 during cardio-pulmonary resuscitation correlates with return of spontaneous circulation.24 Modern ventilators also measure peak and plateau inspiratory airway pressure and minute ventilation. Adequacy of oxygenation and ventilation can also be


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Surgery_Schwartz. with return of spontaneous circulation.24 Modern ventilators also measure peak and plateau inspiratory airway pressure and minute ventilation. Adequacy of oxygenation and ventilation can also be confirmed by arterial blood gas analysis.Temperature monitoring is performed using a temperature probe, usually inserted in the esophagus or nasopharynx. Core body temperature can be measured with temperature sensing Foley catheters. Temperature can also be measured at the skin.Several monitors exist that measure depth of anesthesia, including the bispectral index (BIS) monitor and the SedLine monitor. While these monitors were designed to prevent aware-ness under anesthesia, a multicenter trial of over 6000 patients showed that titrating anesthetic concentration to the BIS moni-tor was not superior to titrating anesthetic depth to end-tidal anesthetic concentration with goal MAC greater than 0.7.25Peripheral nerve stimulators should be used to moni-tor depth of neuromuscular blockade. A


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Surgery_Schwartz. to titrating anesthetic depth to end-tidal anesthetic concentration with goal MAC greater than 0.7.25Peripheral nerve stimulators should be used to moni-tor depth of neuromuscular blockade. A train-of-four monitor delivers four successive stimuli over 2 seconds. Presence of four twitches without fade with a ratio of the height of the first twitch to the height of the fourth twitch at least 0.9 suggests adequate reversal of neuromuscular blockade.26 The presence of one or two twitches (absence of the last two or three) is generally suffi-cient for the relaxation required for almost any kind of abdomi-nal or thoracic operation.PERIOPERATIVE EVALUATION AND PREPARATIONThe ASA has adopted basic standards for the evaluation of patients before surgery. These standards require the anesthe-siologist to evaluate the medical status of the patient, develop a plan of anesthetic care, and discuss this plan with the patient and/or the patient’s legal guardian.A preoperative evaluation includes an


Surgery_Schwartz

Surgery_Schwartz. to evaluate the medical status of the patient, develop a plan of anesthetic care, and discuss this plan with the patient and/or the patient’s legal guardian.A preoperative evaluation includes an appropriately detailed medical history, current drug therapy, appropriate physical examination, and review of laboratory and specific testing results. Based on these findings, the anesthesiologist may conclude that a patient is not in optimal medical condition to undergo elective surgery. These findings and opinions are then discussed with the patient’s primary physician or surgeon, and the surgery may be delayed (or cancelled) until the patient’s medical condition is further evaluated and optimized.The medical history obtained at the preoperative visit should include the patient’s previous exposure and experi-ence with anesthesia, as well as any family history of problems with anesthesia. History of atopy is an important aspect of this evaluation in that it may predispose patients to form


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Surgery_Schwartz. and experi-ence with anesthesia, as well as any family history of problems with anesthesia. History of atopy is an important aspect of this evaluation in that it may predispose patients to form antibodies against antigens that may be represented by agents administered during the perioperative period. Concurrent medications should be fully evaluated when circumstances allow, and adverse inter-actions with agents administered during the perioperative period need to be considered. A review of the function of major organ systems should also be performed. The physical examination is targeted primarily at the central nervous system, cardiovascular system, lungs, and airway.Laboratory testing should be based on the patient’s con-dition and the proposed procedure. Otherwise healthy patients usually do not need laboratory testing for minor procedures. Preoperative testing may be necessitated by findings on physi-cal examination; for example, an electrocardiogram should be obtained if an


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Surgery_Schwartz. usually do not need laboratory testing for minor procedures. Preoperative testing may be necessitated by findings on physi-cal examination; for example, an electrocardiogram should be obtained if an irregular heart rhythm is noted, and an echo-cardiogram may be indicated if a new murmur is observed on Brunicardi_Ch46_p2027-p2044.indd 203301/03/19 11:04 AM 2034SPECIFIC CONSIDERATIONSPART IIauscultation. Chest imaging or pulmonary function testing may be indicated if abnormalities are noted on pulmonary examina-tion and may be pertinent to the administration of the anesthetic or the recovery from anesthesia and surgery. Urine pregnancy testing is typically performed on the day of surgery in women of childbearing age.ASA Physical Status AssessmentThe ASA classification system is a scale used to risk-stratify patients for anesthesia and surgery. The scale, ranging from physical status I to VI, is shown in Table 46-5. Patients under-going emergent surgery are denoted by an “E”; for


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Surgery_Schwartz. used to risk-stratify patients for anesthesia and surgery. The scale, ranging from physical status I to VI, is shown in Table 46-5. Patients under-going emergent surgery are denoted by an “E”; for example, an otherwise healthy patient undergoing an appendectomy for appendicitis would be classified as ASA IE. Mortality has shown to increase with increasing ASA physical status, and it has been shown to be higher for patients undergoing emergency surgery.27Airway EvaluationAirway examination can identify most patients in whom management of the airway and conventional endotracheal CLASS 1: Soft palate, fauces, uvula, pillarsCLASS 2: Soft palate, fauces, portion of uvulaCLASS 3: Soft palate, base of uvulaCLASS 4: Hard palate onlyMALLAMPATI CLASSIFICATIONCLASS 1CLASS 2CLASS 3CLASS 4Figure 46-3. The Mallampati classification.Table 46-5American Society of Anesthesiologists physical status classificationASA PHYSICAL STATUSDESCRIPTIONIA healthy patient without systemic diseaseIIA patient with


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Surgery_Schwartz. Mallampati classification.Table 46-5American Society of Anesthesiologists physical status classificationASA PHYSICAL STATUSDESCRIPTIONIA healthy patient without systemic diseaseIIA patient with mild systemic diseaseIIIA patient with severe systemic diseaseIVA patient with severe systemic disease that is a constant threat to lifeVA moribund patient not expected to survive without the operationVIA declared brain-dead patient whose organs are being removed for donationData from American Society of Anesthesiologists: ASA Physical Status Classification System Developed. ASA House of Delegates/Executive Committee. Amended: October 15, 2014.intubation may be difficult. It is vitally important to recognize such patients before administering medications that induce apnea. The Mallampati classification (Fig. 46-3) is based on the structures visualized with maximal mouth opening and tongue protrusion in the sitting position.28 Patients with higher Mallampati classification, in combination with


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Surgery_Schwartz. (Fig. 46-3) is based on the structures visualized with maximal mouth opening and tongue protrusion in the sitting position.28 Patients with higher Mallampati classification, in combination with other airway abnormalities, can be difficult to intubate. Other predictors of difficult intubation include short neck, immobility of the neck,29 a large overbite, a small mandible, or the inability to shift the lower incisors in front of the upper incisors. The thyromental distance, the distance from the thyroid cartilage to the tip of the chin should be greater than 6 cm; thyromental distance of less than 6 cm has been associated with difficult intubation.30 Obesity is also a risk factor for difficult intubation, and neck circumference has been identified as a risk factor for both dif-ficult intubation as well as difficult mask ventilation.31Cardiovascular DiseaseCardiac risk is widely regarded as the most important risk associated with anesthesia and surgery, and it has been the focus of an


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Surgery_Schwartz. as well as difficult mask ventilation.31Cardiovascular DiseaseCardiac risk is widely regarded as the most important risk associated with anesthesia and surgery, and it has been the focus of an enormous amount of scholarship over the past four decades. The revised cardiac risk index incorporates six patient and surgical factors to assess a patient’s risk of major adverse cardiac events in the perioperative period: history of ischemic heart disease, congestive heart failure, cerebrovascular dis-ease, diabetes requiring insulin, chronic kidney disease with baseline creatinine greater than 2, and whether the surgery is in a high-risk area, namely major vascular, intraperitoneal, or intrathoracic. In 2014, the American College of Cardiology and the American Heart Association published guidelines for perioperative workup and management of patients with cardio-vascular disease; a simplified version is seen in Fig. 46-4 . Notably, this guideline stresses the importance of func-tional status


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Surgery_Schwartz. for perioperative workup and management of patients with cardio-vascular disease; a simplified version is seen in Fig. 46-4 . Notably, this guideline stresses the importance of func-tional status in determining need for further evaluation; patients with good functional status can typically proceed to surgery without additional evaluation. Functional capacity is measured in metabolic equivalents (METs), with patients unable to attain 4 METs considered to have poor functional status. Activities representing 4 METs including walking up a flight of stairs, climbing a hill, or walking on level ground at 3 to 4 miles per hour.3233Brunicardi_Ch46_p2027-p2044.indd 203401/03/19 11:04 AM 2035ANESTHESIA FOR SURGICAL PATIENTSCHAPTER 46These recent guidelines have minimized the role of routine screening. Preoperative electrocardiograms and stress testing are unnecessary for asymptomatic patients undergoing low-risk surgery.Special attention is required for patients with coronary stents.


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Surgery_Schwartz. screening. Preoperative electrocardiograms and stress testing are unnecessary for asymptomatic patients undergoing low-risk surgery.Special attention is required for patients with coronary stents. Elective surgery should be delayed a stent has been inserted, which allows time for it to stabilize and the risk of in-stent thrombosis to decrease. The ACC/AHA guidelines rec-ommend delaying elective surgery for 30 days after bare metal stent placement and for 1 year after drug eluting stent place-ment. Dual antiplatelet therapy should be continued for urgent or emergent procedures that take place before the minimum recommended waiting period.32 For semi-elective surgeries in patients with drug-eluting stents, where the risk of delaying sur-gery is greater than the risk of in-stent thrombosis, ACC/AHA guidelines recommend surgery be delayed for 180 days.Current recommendation is that β-blockers and statins should be continued in patients who are on them chronically. β-Blockers may be


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Surgery_Schwartz. ACC/AHA guidelines recommend surgery be delayed for 180 days.Current recommendation is that β-blockers and statins should be continued in patients who are on them chronically. β-Blockers may be started in the perioperative period for patients with multiple RCRI risk factors or who are at intermediate or high risk for myocardial ischemia. If started in the perioperative period, β-blockers should be started long enough before sur-gery to ascertain their safety, and not on the day of surgery.32,33 Recent large randomized trials have demonstrated excess risk of mortality and stroke simultaneously with decreased risk of myocardial events in moderateand high-risk patients who are newly treated with β-blockers in the periprocedural setting.34,35Implanted cardiac devices including pacemakers and implantable cardioverter-defibrillators also have important peri-operative implications. A 2011 ASA practice advisory stressed the importance of determining whether electromagnetic interfer-ence is


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Surgery_Schwartz. implantable cardioverter-defibrillators also have important peri-operative implications. A 2011 ASA practice advisory stressed the importance of determining whether electromagnetic interfer-ence is likely to occur during the planned procedure, determin-ing the current function and necessity of the implanted device, determining whether reprogramming or temporary disabling of the device is advantageous, having alternative therapy available for the time that the device is unavailable, and restoring device function in the postoperative period.36Pulmonary DiseaseChronic pulmonary disease is an increasingly recognized cause of morbidity and mortality in surgical patients. For patients with asthma or chronic obstructive pulmonary disease, exercise toler-ance and the frequency and severity of exacerbations should be evaluated. A focused history, including prior admissions and intubations for exacerbations, should be obtained. Treatment with bronchodilators in the perioperative setting is


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Surgery_Schwartz. exacerbations should be evaluated. A focused history, including prior admissions and intubations for exacerbations, should be obtained. Treatment with bronchodilators in the perioperative setting is appropri-ate, although there is no literature to either guide this care or to document a benefit from it. Most inhaled anesthetics act as bronchodilators.37 Desflurane can be an airway irritant, and it is often avoided in patients with reactive airway disease.The incidence of obstructive sleep apnea (OSA) has risen with the incidence of obesity. In 2014 the ASA published guide-lines for perioperative management of patients with OSA. These guidelines highlight the importance of identifying patients with obstructive sleep apnea during preoperative evaluation and obtaining a sleep study if appropriate. They also highlight the importance of the development of protocols by anesthesiologists and surgeons to manage OSA in the perioperative setting. There is consensus that these patients should


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Surgery_Schwartz. They also highlight the importance of the development of protocols by anesthesiologists and surgeons to manage OSA in the perioperative setting. There is consensus that these patients should not be extubated until they are completely awake, and that they should be treated with ACC/AHA algorithm of cardiac evaluation for noncardiac surgeryProceed to surgery with medical riskreduction and perioperative surveillancePostpone surgery until stabilized or correctedNo clinicalpredictorsProceed with surgeryProceed with surgery˜1 clinicalpredictorsIntermediate riskor vascular surgeryProceed with surgeryProceed to surgery with heart ratecontrol or consider noninvasive testingif it will change managementEmergency surgeryActive cardiac conditions• Unstable coronary syndromes (unstable or severe angina, recent MI)• Decompensated heart failure (HF; new onset, NYHA class IV)• Significant arrhythmias (Mobitz ll or third-degree heart block, supraventricular tachycardia or atrial fibrillation with


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Surgery_Schwartz. recent MI)• Decompensated heart failure (HF; new onset, NYHA class IV)• Significant arrhythmias (Mobitz ll or third-degree heart block, supraventricular tachycardia or atrial fibrillation with rapid ventricular rate (>100), symptomatic ventricular arrhythmia or bradycardia, new ventricular tachycardia)• Severe valvular disease (severe aortic or mitral stenosis)Step 1Step 2Low-risk surgery (risk <1%)• Superficial or endoscopic• Cataract, breast• Ambulatory surgeryStep 3Functional capacityGood; ≥4 METS (can walk flight of stairs without symptoms)Step 4Clinical predictors• Ischemic heart disease• Compensated or prior HF• Cerebrovascular disease (stroke, TIA)• Diabetes mellitus• Renal insufficiencyStep 5Figure 46-4. Simplified cardiac evaluation for noncardiac surgery. (Data from Eagle KA, Berger PB, Calkins H, et al: ACC/AHA guideline update for perioperative cardiovascular evaluation for noncardiac surgery–executive summary: a report of the American College of Cardiology/American


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Surgery_Schwartz. KA, Berger PB, Calkins H, et al: ACC/AHA guideline update for perioperative cardiovascular evaluation for noncardiac surgery–executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Update the 1996 Guidelines on Perioperative Cardiovascular Evaluation for Noncardiac Surgery), J Am Coll Cardiol. 2002 Feb 6;39(3):542-553.)Brunicardi_Ch46_p2027-p2044.indd 203501/03/19 11:04 AM 2036SPECIFIC CONSIDERATIONSPART IInoninvasive positive pressure ventilation in the postoperative period as indicated.38Renal DiseaseManagement of anesthesia in patients with chronic renal insuf-ficiency requires close attention to perioperative fluid man-agement and acid-base and electrolyte homeostasis. Doses of opioids and neuromuscular agents are typically reduced and dosing intervals increased to compensate for decreased renal excretion. Cisatracurium is often chosen as the muscle relax-ant in patients with severe renal


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Surgery_Schwartz. agents are typically reduced and dosing intervals increased to compensate for decreased renal excretion. Cisatracurium is often chosen as the muscle relax-ant in patients with severe renal insufficiency because its elimi-nation is unchanged by renal failure. Sugammadex, a reversal agent for steroid-based neuromuscular blockers, is not currently recommended for use in patients with advanced chronic kidney disease or end-stage renal disease.Hepatic DiseaseHepatic dysfunction has many causes, and it can compel significant changes in anesthetic care. First, anesthetic agents metabolized in the liver can accumulate in these patients and may have a longer duration of effect. To mitigate this, short-acting agents are strongly preferred in these patients. Hypoalbuminemia can paradoxically increase the free plasma levels of drugs, which can also exagger-ate their effects. In patients with substantial ascites, high intra-abdominal pressure may increase the risk of passive gastric reflux, and


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Surgery_Schwartz. the free plasma levels of drugs, which can also exagger-ate their effects. In patients with substantial ascites, high intra-abdominal pressure may increase the risk of passive gastric reflux, and thus many such patients are managed as if they have a full stomach, regardless of how long they have been NPO. In patients with significant hepatocellular dysfunction and/or portal hyperten-sion, the combination of thrombocytopenia and coagulation factor deficiency not only increase the risk of bleeding associated with surgery, they also are relative or absolute contraindications to a variety of anesthetic techniques, such as subarachnoid blocks and epidural anesthesia. Presence of esophageal varices increases the risk of gastric tubes and transesophageal echocardiography.Endocrine DiseasePerioperative management of the diabetic patient can be espe-cially challenging. A hemoglobin A1c level should be obtained if a recent level is not available, as an increased A1c level is asso-ciated with an


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Surgery_Schwartz. management of the diabetic patient can be espe-cially challenging. A hemoglobin A1c level should be obtained if a recent level is not available, as an increased A1c level is asso-ciated with an increase in perioperative complications including wound infections.39-41 Several institutions have implemented pro-tocols for glucose management for diabetic patients undergoing surgery, although recommendations differ on appropriate target glucose levels.39,42,43 Perhaps the most important thing for a prac-titioner to know and remember is that the difference between type 1 and type 2 diabetes is important, and that these two differ-ent diseases require different approaches to their management. In general, patients with type 2 diabetes have a lower risk of becom-ing hypoglycemic, tend to have higher blood sugars at baseline, and tolerate higher levels of serum glucose without significant acute hazard. Patients with type 1 diabetes, who are deficient in insulin production and thus require


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Surgery_Schwartz. higher blood sugars at baseline, and tolerate higher levels of serum glucose without significant acute hazard. Patients with type 1 diabetes, who are deficient in insulin production and thus require insulin administration to pre-vent ketosis, are far more likely to become hypoglycemic when subjected to stress, and they are also at risk for developing keto-acidosis with hyperglycemia. Patients with type 1 diabetes merit more careful monitoring of their blood sugars in the periopera-tive setting than patients with type 2 diabetes.44-47Preoperative FastingThe ASA has developed specific guidelines for preoperative fasting to mitigate the risk of aspiration of gastric contents. Table 46-6 shows guidelines for preoperative food and fluid intake for elective procedures. Individual patients may need lengthier fasting times than the guidelines indicate. Notably, a rapid sequence induction and intubation should be considered in patients who are at higher risk for aspiration such as those with


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Surgery_Schwartz. need lengthier fasting times than the guidelines indicate. Notably, a rapid sequence induction and intubation should be considered in patients who are at higher risk for aspiration such as those with very symptomatic gastroesophageal reflux, achala-sia, gastroparesis, or dysmotility, regardless of fasting status.48Patients With Advanced DirectivesPatients with do not resuscitate (DNR) and/or do not intu-bate (DNI) orders present a unique challenge. Patients or their power-of-attorney may choose to rescind these directives in the perioperative period, maintain them as originally ordered, or modify them to allow for a limited resuscitation. Both the ASA and the American College of Surgeons recommend that preoperative discussions with the patient and their family clarify the patient’s wishes, and both societies emphasize that policies that mandate uniform enforcement or disregarding of all DNR orders take away patients’ right to self-determination.49,50Risk EstimationSeveral risk


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Surgery_Schwartz. wishes, and both societies emphasize that policies that mandate uniform enforcement or disregarding of all DNR orders take away patients’ right to self-determination.49,50Risk EstimationSeveral risk calculators have been developed to estimate peri-operative morbidity and mortality. The American College of Surgeons National Surgical Quality Improvement Program (NSQIP) surgical risk calculator allows for estimation of risk of eight different adverse outcomes, including mortality.51 The Society of Thoracic Surgeons risk calculator estimates risk of morbidity and mortality after cardiac surgical procedures.52 While such risk estimators can provide widely differing esti-mates or may be inaccurate in certain situations,53 they are still invaluable aids for discussions with patients and their families about high-risk surgery.INTRAOPERATIVE MANAGEMENTGeneral AnesthesiaGeneral anesthesia remains the cornerstone of anesthesia prac-tice; many surgical procedures cannot be done under regional


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Surgery_Schwartz. families about high-risk surgery.INTRAOPERATIVE MANAGEMENTGeneral AnesthesiaGeneral anesthesia remains the cornerstone of anesthesia prac-tice; many surgical procedures cannot be done under regional techniques or monitored anesthesia care with sedation.The induction of general anesthesia can precipitate cata-strophic anesthetic complications. Many different techniques can be used to induce general anesthesia, each with significant advantages and disadvantages.Intravenous induction, used primarily in adults, quickly produces unconsciousness, and depending on the agent used, apnea as well. Propofol, the most common induction agent currently used, can cause hypotension due to its myocardial depressing and vasodilatory properties. Hypertension and 4Table 46-6Guidelines for food and fluid intake before elective surgeryTIME BEFORE SURGERYFOOD OR FLUID INTAKEUp to 8 hoursFood and fluids as desiredUp to 6 hoursaLight meal, infant formulaUp to 4 hoursBreast milkUp to 2 hoursClear liquids


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Surgery_Schwartz. intake before elective surgeryTIME BEFORE SURGERYFOOD OR FLUID INTAKEUp to 8 hoursFood and fluids as desiredUp to 6 hoursaLight meal, infant formulaUp to 4 hoursBreast milkUp to 2 hoursClear liquids onlyaLight meal refers to a limited amount of easily digestible food, such as toast or crackers. Individual patients may need lengthier fasting times than these guidelines indicate.Adapted with permission from Longnecker DE, Mackey SC, Newman MF, et al: Anesthesiology, 3rd ed. New York, NY: McGraw-Hill Education; 2018.Brunicardi_Ch46_p2027-p2044.indd 203601/03/19 11:04 AM 2037ANESTHESIA FOR SURGICAL PATIENTSCHAPTER 46tachycardia commonly occur during laryngoscopy or other sig-nificant airway stimulation.The goal of a rapid sequence induction (RSI) is to achieve secure protection of the airway with a cuffed endotracheal tube without ever mask ventilating a patient. It is intended to prevent vomiting and aspiration, and it is routinely employed in patients at heightened risk for


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Surgery_Schwartz. the airway with a cuffed endotracheal tube without ever mask ventilating a patient. It is intended to prevent vomiting and aspiration, and it is routinely employed in patients at heightened risk for aspiration. There are no randomized con-trolled trials that demonstrate any kind of outcome benefit of rapid sequence induction in such patients, but it is nevertheless routinely employed for this purpose in the United States.Pediatric patients are often not amenable to preoperative IV catheter placement. Hence, inhalation induction of anesthe-sia is commonly used in children, with IV placement occur-ring after induction. Even among children, however, patients at heightened risk for aspiration or with a full stomach may be best managed with preoperative IV placement and an IV induction. Patients with developmental delay may not be amenable to pre-operative IV placement or inhalational induction of anesthesia. In such patients, intramuscular administration of an agent such as ketamine is


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Surgery_Schwartz. with developmental delay may not be amenable to pre-operative IV placement or inhalational induction of anesthesia. In such patients, intramuscular administration of an agent such as ketamine is often required to induce anesthesia.Airway Management. Most anesthesiologists prefer to secure the airway of a patient undergoing general anesthesia, and this is usually accomplished immediately after anesthesia has been induced. The airway may be managed in several ways, includ-ing by face mask, with a laryngeal mask airway (LMA), or, most definitively, by endotracheal intubation with a cuffed endotracheal tube. Nasal and oral airways can help establish a patent airway in a patient being ventilated with a mask by creat-ing an air passage behind the tongue.The LMA is a cuffed supraglottic oral airway that is inserted through the oropharynx and ideally positioned just above the glottis opening. It is passed blindly, and the inflated cuff creates a seal around the laryngeal inlet. An LMA does


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Surgery_Schwartz. that is inserted through the oropharynx and ideally positioned just above the glottis opening. It is passed blindly, and the inflated cuff creates a seal around the laryngeal inlet. An LMA does not protect against aspiration and should generally not be used in patients with a high risk of aspiration.Tracheal intubation requires a skilled operator and proper equipment. In most elective anesthetics, attempts to intubate the trachea are facilitated by the administration of muscle relaxants in a patient who is already under a general anesthetic. Intubation is typically performed under direct visualization with a laryn-goscope, watching the endotracheal tube pass through the vocal cords into the trachea. To obtain a direct line of sight, the patient is placed in the sniffing position. The neck is flexed at the lower cervical spine and extended at the atlanto-occipital joint. This flexion and extension are amplified during laryngoscopy. Laryn-goscope blades can be curved (Macintosh) or


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Surgery_Schwartz. neck is flexed at the lower cervical spine and extended at the atlanto-occipital joint. This flexion and extension are amplified during laryngoscopy. Laryn-goscope blades can be curved (Macintosh) or straight (Miller) blades. Laryngoscopic views are typically reported in a classi-fication system developed by Cormack and Lehane (Fig. 46-5).Management of the Difficult Airway. Some patients have physical characteristics or a history suggestive of difficulty in placing an endotracheal tube. A short neck, limited neck mobil-ity, small interincisor distance, short thyromental distance, and high Mallampati classes may all represent a challenge to Figure 46-5. Laryngoscopic views obtained per Cormack and Lehane.Figure 46-6. Video laryngoscopy with the GlideScope.endotracheal intubation. Several tools have been developed to assist in management of the difficult airway.The Glidescope, a video laryngoscope, allows for visualiza-tion of the larynx on a video screen (Fig. 46-6). Having more of a


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Surgery_Schwartz. tools have been developed to assist in management of the difficult airway.The Glidescope, a video laryngoscope, allows for visualiza-tion of the larynx on a video screen (Fig. 46-6). Having more of a bend than a standard curved Macintosh blade, it can be advanta-geous for visualizing and intubating the trachea in patients with large tongues or relatively anterior glottis openings. Placement of the endotracheal tube once the larynx has been visualized can still be challenging. A recent study of ICU patients requiring intubation showed that video laryngoscopy did not improve first-pass orotracheal intubation success rate and was associated with higher rates of severe life-threatening complications.54The intubating laryngeal mask airway (ILMA) is an advanced form of LMA designed to maintain a patent airway and facilitate tracheal intubation. The ILMA can be placed in anticipated or unexpectedly difficult airways as an airway res-cue device and as a guide for intubating the trachea. The


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Surgery_Schwartz. a patent airway and facilitate tracheal intubation. The ILMA can be placed in anticipated or unexpectedly difficult airways as an airway res-cue device and as a guide for intubating the trachea. The device itself is substantially more rigid than other laryngeal mask airways, and includes a handle which the operator can use to displace the opening of the device. A specially manufactured endotracheal tube can be passed blindly through the ILMA into the larynx, or the ILMA can be used as a conduit for a flex-ible fiberoptic scope. Experience with airway management in general and the use of this device in particular is essential for its effective use in emergency situations; operators with little experience will enjoy little success with this device.The flexible fiberoptic intubation bronchoscope is the gold standard for difficult intubation. It is indicated in difficult or compromised airways where neck extension is not desirable or in cases with risk of dental damage. The flexible


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Surgery_Schwartz. is the gold standard for difficult intubation. It is indicated in difficult or compromised airways where neck extension is not desirable or in cases with risk of dental damage. The flexible bronchoscope allows excellent visualization of the airway and glottic open-ing. This technique can be used for oral and nasal intubation, for awake or asleep intubation, and for intubation in the awake, spontaneously ventilating patient whose airway has been treated with topical local anesthetic.The ASA has developed an algorithm for management of the difficult airway (Fig. 46-7).55 Notably, in patients in whom Brunicardi_Ch46_p2027-p2044.indd 203701/03/19 11:04 AM 2038SPECIFIC CONSIDERATIONSPART IIFigure 46-7. ASA difficult airway algorithm. (Reproduced with permission from Apfelbaum JL, Hagberg CA, Caplan RA, et al: Practice guidelines for management of the difficult airway: an updated report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway,


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Surgery_Schwartz. CA, Caplan RA, et al: Practice guidelines for management of the difficult airway: an updated report by the American Society of Anesthesiologists Task Force on Management of the Difficult Airway, Anesthesiology. 2013 Feb;118(2):251-270.)Brunicardi_Ch46_p2027-p2044.indd 203801/03/19 11:04 AM 2039ANESTHESIA FOR SURGICAL PATIENTSCHAPTER 46both intubation and ventilation are impossible, the algorithm calls for placement of an LMA with ventilation attempted through the LMA.Monitored Anesthesia CareMonitored anesthesia care (MAC) is when a patient under-goes a procedure under local anesthesia under the care of an anesthesiologist who can provide sedation as indicated. Seda-tion is administered to a level that allows the patient to main-tain airway reflexes and breath spontaneously. Advantages of MAC anesthesia include reduced invasiveness, as the airway is not manipulated, and faster recovery. ASA standard moni-tors must be used, including capnography, which allows for rapid detection of


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Surgery_Schwartz. of MAC anesthesia include reduced invasiveness, as the airway is not manipulated, and faster recovery. ASA standard moni-tors must be used, including capnography, which allows for rapid detection of apnea or hypoventilation. In some instances, most commonly for gastroenterology procedures, patients are administered an intravenous anesthetic that is often classified as a MAC, even though the patient is so deeply anesthetized that they have no significant response to significant airway stimula-tion; the airway is monitored by the anesthesia provider and secured if necessary.Regional Anesthesia/Acute PainRegional anesthesia allows for selective blockade and is an excellent anesthetic option for several different types of pro-cedures. Regional anesthesia can also provide excellent post-operative pain control. Regional techniques include neuraxial blockade, including spinal and epidural anesthetics, peripheral nerve blocks, and truncal blocks.Spinal anesthetics (also referred to as


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Surgery_Schwartz. pain control. Regional techniques include neuraxial blockade, including spinal and epidural anesthetics, peripheral nerve blocks, and truncal blocks.Spinal anesthetics (also referred to as subarachnoid blocks) can be used for lower extremity, lower abdominal, pelvic, and urologic and gynecologic procedures. A small caliber needle (typically 25-gauge or smaller) is inserted into the intrathecal space in the cauda aquina and below the conus medularis, and a small volume of local anesthetic is injected. Duration and level of the block in the spinal cord is affected by the anesthetic used, the dose employed, and baricity of solution injected. Complica-tions can include hypotension, bradycardia, postdural puncture headache, injury to local structures or nerves, and hematoma formation. The American Society of Regional Anesthesia pub-lishes guidelines regarding safe intervals to perform neuraxial anesthetics after the administration of anticoagulant and anti-platelet agents.An epidural


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Surgery_Schwartz. American Society of Regional Anesthesia pub-lishes guidelines regarding safe intervals to perform neuraxial anesthetics after the administration of anticoagulant and anti-platelet agents.An epidural catheter can be used as a primary anesthetic for a procedure, or it can be placed preoperatively and used in conjunction with a general anesthetic for postoperative pain control. Epidural catheters can be placed in the thoracic or lumbar spine and can remain in place for days after surgery. A dilute local anesthetic and/or opioid is administered through the catheter to provide analgesia. Complications of epidural anesthesia are similar to that of spinal anesthesia. In addition to improved pain control, benefits of epidural anesthesia include reduced pulmonary complications56 and decreased duration of postoperative ileus.57Peripheral nerve blockade can also be used to provide sur-gical anesthesia as well as postoperative analgesia, particularly for surgeries of the upper or lower


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Surgery_Schwartz. duration of postoperative ileus.57Peripheral nerve blockade can also be used to provide sur-gical anesthesia as well as postoperative analgesia, particularly for surgeries of the upper or lower extremities. The nerve or plexus of interest is located with ultrasound and/or peripheral nerve stimulator, and local anesthetic is injected around the nerve. Single-shot nerve blocks allow for surgical anesthesia and immediate postoperative analgesia and can last for several hours. Flexible catheters can also be placed in proximity to nerves to allow for continuous infusion and blockade that can continue for several days. Complications of peripheral nerve blocks include injury to nerves or nearby structures and local anesthetic systemic toxicity.Recently, truncal blocks have become more commonly and widely used for the treatment of postoperative pain. Trun-cal blocks include the transversus abdominis plane (TAP) block, the rectus sheath block, the pectoral nerve block, and the serra-tus


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Surgery_Schwartz. and widely used for the treatment of postoperative pain. Trun-cal blocks include the transversus abdominis plane (TAP) block, the rectus sheath block, the pectoral nerve block, and the serra-tus anterior plane block. These truncal blocks are usually done under ultrasound guidance with local anesthetic injected in the appropriate plane. Truncal blocks are typically performed as part of a multimodal approach to postoperative pain. Limited evidence suggests that use of truncal blocks decreases postop-erative opioid requirements.58,59RECOVERY AND COMPLICATIONSThe Postanesthesia Care UnitThe advent of the modern postanesthesia care unit represents a major advance in the safety of perioperative care, as the close monitoring that occurs there can prevent or expedite the man-agement of a variety of serious complications. Ventilation, oxygenation, hemodynamics, temperature, nausea, and pain are closely monitored in the PACU, with close attention also given to urine output, ongoing bleeding,


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Surgery_Schwartz. of serious complications. Ventilation, oxygenation, hemodynamics, temperature, nausea, and pain are closely monitored in the PACU, with close attention also given to urine output, ongoing bleeding, and drainage. To be dis-charge eligible, patients should have returned to their baseline mental status, be oxygenating and ventilating adequately, have adequate pain control, and have stable vital signs. There are multiple scoring systems that can be used assess suitability for discharge from PACU.60-62 Postoperative hemorrhage, hyper-tension or hypotension, myocardial ischemia, arrhythmias, and altered mental status commonly manifest in the postoperative care unit. Postoperative nausea and vomiting (PONV) occurs in 20% to 30% of surgical cases,63 and it is a common cause of increased PACU length of stay and increased cost of PACU stay.64 For this reason, many or most patients undergoing gen-eral anesthesia receive prophylactic antiemetics.Enhanced Recovery After Surgery PathwaysEnhanced


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Surgery_Schwartz. of stay and increased cost of PACU stay.64 For this reason, many or most patients undergoing gen-eral anesthesia receive prophylactic antiemetics.Enhanced Recovery After Surgery PathwaysEnhanced recovery after surgery (ERAS) pathways are multi-modal perioperative care pathways designed to hasten recovery after elective surgery. These pathways may include preoperative education and counseling, preoperative optimization, limiting preoperative bowel preparation, limiting preoperative fasting, providing multimodal analgesia (including regional anesthesia) as appropriate, minimizing intraoperative fluid administration, and early mobilization. ERAS pathways have been shown to reduce duration of hospitalization and reduce cost of periopera-tive care.65-67Acute Postoperative PainThe management of postoperative pain has changed dra-matically in the modern era, with multimodal approaches and regional techniques reducing the use of opiates. Regardless, opioids remain the mainstay of


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Surgery_Schwartz. of postoperative pain has changed dra-matically in the modern era, with multimodal approaches and regional techniques reducing the use of opiates. Regardless, opioids remain the mainstay of intraoperative and postoperative analgesia, especially for larger and more invasive procedures. Patients with chronic pain or opiate tolerance can present a unique challenge in the perioperative period, and they can ben-efit from regional and multimodal approaches. Such patients may benefit from early involvement of an acute pain medicine specialist.For the past decade, pain has been described as the fifth vital sign, and physicians have been strongly encouraged to 5Brunicardi_Ch46_p2027-p2044.indd 203901/03/19 11:04 AM 2040SPECIFIC CONSIDERATIONSPART IIaggressively treat pain in their patients. Generally speaking, physicians sought to accomplish this goal through the more liberal use of opiates. Opioid prescription has thus soared in recent years. Some studies suggest that 3% to 7% of surgical


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Surgery_Schwartz. speaking, physicians sought to accomplish this goal through the more liberal use of opiates. Opioid prescription has thus soared in recent years. Some studies suggest that 3% to 7% of surgical patients prescribed opioids in the postoperative period continue to use them for a prolonged period after surgery,68,69 suggesting that opioid abuse often begins in the postoperative period. The U.S. Centers for Disease Control and Prevention has recently declared that prescription drug abuse is an epidemic.70 Physi-cians and surgeons will have to continue to seek the fine line between adequate pain control and prescribing patterns that enable dependence.Malignant HyperthermiaMalignant hyperthermia (MH) is a hereditary, life-threatening, hypermetabolic disorder, developing during or after receiving general anesthesia. The clinical incidence of MH ranges from 1:10000 to 1:250,000.71 A genetic predisposition and expo-sure to one or more triggering agents are necessary to evoke MH. Triggering


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Surgery_Schwartz. general anesthesia. The clinical incidence of MH ranges from 1:10000 to 1:250,000.71 A genetic predisposition and expo-sure to one or more triggering agents are necessary to evoke MH. Triggering agents include all volatile anesthetics (e.g., isoflurane, sevoflurane, and desflurane) and the depolarizing neuromuscular blocker succinylcholine. Volatile anesthetics and/or succinylcholine cause a rise in the myoplasmic cal-cium concentration in susceptible patients, causing persistent muscle contraction, the production of large quantities of car-bon dioxide and lactic acid, and a relentless increase in body temperature.MH is often an autosomal dominant disorder associated with several gene loci, predominantly the ryanodine receptor gene RYR1. MH can be diagnosed with the caffeine-contracture halothane test, which requires a muscle biopsy. Genetic testing can be helpful after an episode of MH. There is no simple, reli-able blood screening test yet available for diagnosis.The classic MH


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Surgery_Schwartz. halothane test, which requires a muscle biopsy. Genetic testing can be helpful after an episode of MH. There is no simple, reli-able blood screening test yet available for diagnosis.The classic MH crisis entails a hypermetabolic state with tachycardia and increased end-tidal CO2. Relentless muscle con-traction causes respiratory and metabolic acidosis, as well as rhabdomyolysis, arrhythmias, hyperkalemia, and even sudden cardiac arrest. Hyperthermia typically occurs after the episode is well under way. Treatment must be aggressive and begin as soon as a case of MH is suspected. Volatile anesthetics should be stopped immediately and dantrolene given at an initial dose of 2.5 mg/kg intravenously. The national MH hotline should be contacted for help in managing any patient with MH. Patients should be monitored in the intensive care setting for possible recrudescence of MH.Cardiovascular ComplicationsHemodynamic perturbations are a common in the periopera-tive period. Arrhythmias may


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Surgery_Schwartz. should be monitored in the intensive care setting for possible recrudescence of MH.Cardiovascular ComplicationsHemodynamic perturbations are a common in the periopera-tive period. Arrhythmias may begin before, during, and after an anesthetic, and are particularly common after cardiothoracic and esophageal surgery. Hypotension may be due to anemia, hypovolemia, myocardial ischemia or dysfunction, or other less common events such as pulmonary embolism and ana-phylactic reactions. Hypertension is also common, particularly when antihypertensive regimens are altered in the perioperative period.Respiratory FailureRespiratory insufficiency and failure occur frequently in the postoperative period. Respiratory depression can occur as a con-sequence of residual neuromuscular blockade, residual inhaled anesthetics, or opioids. Mechanical airway obstruction can be ameliorated by rescue maneuvers, or insertion of an oral or nasal airway. It is imperative to evaluate and treat anesthesia-related


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Surgery_Schwartz. anesthetics, or opioids. Mechanical airway obstruction can be ameliorated by rescue maneuvers, or insertion of an oral or nasal airway. It is imperative to evaluate and treat anesthesia-related causes of respiratory insufficiency. The opioid antagonist nalox-one can be given for opioid related respiratory insufficiency, and an additional reversal agent can be given for residual neuromus-cular weakness. Respiratory failure can reasonably be managed with noninvasive positive pressure ventilation in many cases72; patients who fail this or are unlikely to benefit from it should be intubated. High-flow nasal cannula is increasingly being used for postextubation respiratory failure,73 and several studies have demonstrated its benefit in postoperative patients.74-77Neurologic and Psychiatric ComplicationsPerioperative neurologic and psychiatric complications include stroke, both ischemic and hemorrhagic, postoperative delirium, and postoperative cognitive dysfunction. Treatment of


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Surgery_Schwartz. ComplicationsPerioperative neurologic and psychiatric complications include stroke, both ischemic and hemorrhagic, postoperative delirium, and postoperative cognitive dysfunction. Treatment of periop-erative stroke may be difficult as initiation of anticoagulation or thrombolysis may not be safe after surgery. Postoperative delirium is common and transient. Treatment includes reorienta-tion, treatment of pain, workup for metabolic, hemodynamic, or respiratory perturbations, and consideration of the side effects of the anesthetics and analgesics administered. Antipsychotics such as haloperidol can be useful in the treatment of postopera-tive delirium.78 Postoperative cognitive dysfunction (POCD) is a decline in cognitive function that may last days or may persist for months. Risk factors for persistent POCD include advanced age, history of prior stroke, and lower educational level.79 POCD rates among older adult patients have been shown to be as high as 40% at hospital discharge and


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Surgery_Schwartz. for persistent POCD include advanced age, history of prior stroke, and lower educational level.79 POCD rates among older adult patients have been shown to be as high as 40% at hospital discharge and 12% 3 months after surgery. Notably, a causal link has not been established between administration of anesthesia and development of POCD, sug-gesting that it may be the physiologic stress of the perioperative experience that may lead to a decline in cognitive function in such patients.80CONCLUSIONThe practice of anesthesia has improved dramatically over the past century. Advances in training, pharmacology, anesthesia equipment, and monitoring have not only made anesthesia dra-matically safer but have also allowed ever sicker patients to benefit from surgery.REFERENCESEntries highlighted in bright blue are key references. 1. Haridas RP. Horace wells’ demonstration of nitrous oxide in Boston. Anesthesiology. 2013;119:1014-1022. 2. Bigelow HJ. insensibility during surgical operations produced


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Surgery_Schwartz. blue are key references. 1. Haridas RP. Horace wells’ demonstration of nitrous oxide in Boston. Anesthesiology. 2013;119:1014-1022. 2. Bigelow HJ. insensibility during surgical operations produced by inhalation. Boston Med Surg J. 1846;35:309-317. This arti-cle, published in the predecessor to the New England Journal of Medicine, described the first public demonstration of ether at the Massachusetts General Hospital. 3. Buckley K. The most important article in NEJM history. 2012. Available at: https://blogs.nejm.org/now/index.php/explore-the-history-of-medical-discoveries/2012/01/26/. Accessed August 20, 2018. 4. Kim TK OS, Johnson KB. Basic Principles of pharmacology. In: Miller RD, Eriksson LI, Fleisher LA, Wiener-Kronish JP, Cohen N, Young WL, eds. Miller’s Anesthesia. 8th ed. Philadelphia: Elsevier; 2015:590-613. 5. Forman SA, Benkwitz C. Pharmacology of inhalational anesthetics. In: Longnecker DE, Brown DL, Newman MF, Zapol WM, eds. Anesthesiology. New York: McGraw-Hill;


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Surgery_Schwartz. Philadelphia: Elsevier; 2015:590-613. 5. Forman SA, Benkwitz C. Pharmacology of inhalational anesthetics. In: Longnecker DE, Brown DL, Newman MF, Zapol WM, eds. Anesthesiology. New York: McGraw-Hill; 2012:596-616.Brunicardi_Ch46_p2027-p2044.indd 204001/03/19 11:04 AM 2041ANESTHESIA FOR SURGICAL PATIENTSCHAPTER 46 6. Myles PS, Leslie K, Chan MT, et al. The safety of addition of nitrous oxide to general anaesthesia in at-risk patients hav-ing major non-cardiac surgery (ENIGMA-II): a randomised, single-blind trial. Lancet (London, England). 2014;384: 1446-1454. This randomized, controlled trial demonstrated the safety of a largely nitrous-oxide based general anesthetic technique. 7. Dershwitz M RC. Pharmacology of intravenous anesthetics. In: Longnecker DE, Brown DL, Newman MF, Zapol WM, eds. Anesthesiology. New York: McGraw-Hill; 2012:687-702. 8. Wagner RL, White PF, Kan PB, et al. Inhibition of adrenal steroidogenesis by the anesthetic etomidate. N Engl J Med.


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Surgery_Schwartz. Newman MF, Zapol WM, eds. Anesthesiology. New York: McGraw-Hill; 2012:687-702. 8. Wagner RL, White PF, Kan PB, et al. Inhibition of adrenal steroidogenesis by the anesthetic etomidate. N Engl J Med. 1984;310:1415-1421. 9. Annane D, Sebille V, Charpentier C, et al. Effect of treat-ment with low doses of hydrocortisone and fludrocortisone on mortality in patients with septic shock. JAMA. 2002;288: 862-871. 10. McPhee LC, Badawi O, Fraser GL, et al. Single-dose etomidate is not associated with increased mortality in ICU patients with sepsis: analysis of a large electronic ICU database. Crit Care Med. 2013;41:774-783. 11. Absalom A, Pledger D, Kong A. Adrenocortical function in critically ill patients 24 h after a single dose of etomidate. Anaesthesia. 1999;54:861-867. 12. Hohl CM, Kelly-Smith CH, Yeung TC, et al. The effect of a bolus dose of etomidate on cortisol levels, mortality, and health services utilization: a systematic review. Ann Emerg Med. 2010;56:105-113.e105. 13. Mozanski M,


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Surgery_Schwartz. CH, Yeung TC, et al. The effect of a bolus dose of etomidate on cortisol levels, mortality, and health services utilization: a systematic review. Ann Emerg Med. 2010;56:105-113.e105. 13. Mozanski M, Tomaszewski D, Rybicki Z, et al. Etomidate, but not thiopental, decreases serum cortisol concentration in mor-bidly obese patients. A randomized controlled trial. Anaesthe-siol Intensive Ther. 2016;48:7-12. 14. Su S, Ren C, Zhang H, et al. The Opioid-sparing effect of perioperative dexmedetomidine plus sufentanil infusion dur-ing neurosurgery: a retrospective study. Front Pharmacol. 2016;7:407. 15. Jessen Lundorf L, Korvenius Nedergaard H, Moller AM. Peri-operative dexmedetomidine for acute pain after abdominal sur-gery in adults. Cochrane Database Syst Rev. 2016;2:Cd010358. 16. Rosow CE, Dershwitz M. Pharmacology of opioid anesthetics. In: Longnecker DE, Brown DL, Newman MF, Zapol WM, eds. Anesthesiology. New York: McGraw-Hill; 2012:703-724. 17. Kraft M, MacLaren R, Du W, et al. Alvimopan


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Surgery_Schwartz. M. Pharmacology of opioid anesthetics. In: Longnecker DE, Brown DL, Newman MF, Zapol WM, eds. Anesthesiology. New York: McGraw-Hill; 2012:703-724. 17. Kraft M, MacLaren R, Du W, et al. Alvimopan (Entereg) for the management of postoperative ileus in patients undergoing bowel resection. Pharm Therapeut. 2010;35:44-49. 18. Chen L MJ, Mao J. Nonopioid pain medications, In: Miller RD, Eriksson LI, Fleisher LA, Wiener-Kronish JP, Cohen N, Young WL, eds. Miller’s Anesthesia. 8th ed. Philadelphia: Elsevier; 2015:915-918. 19. Weibel S, Jokinen J, Pace NL, et al.. Efficacy and safety of intravenous lidocaine for postoperative analgesia and recovery after surgery: a systematic review with trial sequential analysis. Br J Anaesth. 2016;116:770-783. 20. Christie LE, Picard J, Weinberg GL. Local anaesthetic systemic toxicity. BJA Educ. 2015;15:136-142. 21. Heavner JE. Pharmacology of local anesthetics. In: Longnecker DE, Brown DL, Newman MF, Zapol WM, eds. Anesthesiology. New York: McGraw-Hill;


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Surgery_Schwartz. systemic toxicity. BJA Educ. 2015;15:136-142. 21. Heavner JE. Pharmacology of local anesthetics. In: Longnecker DE, Brown DL, Newman MF, Zapol WM, eds. Anesthesiology. New York: McGraw-Hill; 2012:767-782. 22. Naguib M, Lien C, Meistelman C. Pharmacology of neuromus-cular blocking drugs. In: Miller RD, Eriksson LI, Fleisher LA, Wiener-Kronish JP, Cohen N, Young WL, eds. Miller’s Anes-thesia. 8th ed. Philadelphia: Elsevier; 2015:958-994. 23. Naguib M, Samarkandi AH, El-Din ME, et al. The dose of succinylcholine required for excellent endotracheal intubating conditions. Anesth Analg. 2006;102:151-155. 24. Kodali BS, Urman RD. Capnography during cardiopulmonary resuscitation: current evidence and future directions. J Emerg Trauma Shock. 2014;7:332-340. This article reviews the impor-tance of capnography during cardiopulmonary resuscitation. 25. Avidan MS, Jacobsohn E, Glick D, et al. Prevention of intraoperative awareness in a high-risk surgical population. N Engl J Med. 2011;365:591-600.