Anesthesia Complications

Chapter 53


Anesthesia Complications



Every day healthcare professionals practice within enormously complex environments; unexpected patient outcomes or complications can occur at any time. Public interest regarding patient safety has increased significantly over the past decade, largely as a result of the staggering number of preventable deaths cited in the Institute of Medicine’s (IOM) 1999 landmark report.1 The results of this report led to implementation of a broad range of improvement efforts concentrating on the prevention and detection of errors in health care. Complications can arise as consequences of another concurrent disease or of mishap. Often these complications appear unexpectedly, and they have been experienced by well-intentioned healthcare professionals who are surrounded by complex clinical conditions, poorly designed processes, and suboptimal communication patterns.2,3


This chapter is more than a simple compilation and review of various types of anesthetic complications. Our goal is to provide more insight into common and emerging types of anesthetic complications and to introduce organizational concepts that often surround complications in anesthesia. We discuss how to deal with complications systematically and examine the underlying human factors and lapses in communication involved in the development of critical incidents.



Mortality in Anesthesia


Risks related to anesthesia have declined over the past several decades; however, the exact cause of this decline is unclear.4 Anesthesia has had a 10-fold decrease in mortality since the 1980s and is often cited as reaching a six-sigma defect rate (99.99966% of end-products are statistically free of defects or 3.4 defects per million).4,5 Outcome measures studied related to the risk of anesthesia include mortality, morbidity, patient satisfaction, and quality of life.6 Perioperative risk related to anesthesia is multifactorial and depends on several interactions between the anesthesia, surgical procedure, and patient health. Increased safety measures (e.g., use of pulse oximetry) would be expected to improve outcomes, but no randomized controlled trials have been able to document such a conclusion.7


It is difficult to use mortality data to extrapolate conclusions about the safety of anesthesia, because no standard definition of what anesthesia mortality really is has been established. In addition, significant morbidity involving patients who do not die has not been considered in regard to safety. Some perioperative mortality data mainly include perioperative death to which human error has contributed versus all causes of death during or after anesthesia.4,8 Secondly, there is a lack of consensus related to the period of time after anesthesia that should define anesthesia-related mortality. Depending on which studies are referenced, this time frame can vary from 24 hours to 30 days after anesthesia.


Another issue that clouds outcome data related to morbidity and mortality is that older patients with multi-morbidities are now considered operable as a result of improved technology (e.g., less invasive procedures) resulting in higher perioperative surgical and anesthetic risk.7 Actual data are difficult to analyze because most studies use coroner’s registries, voluntary reports, surveys, and malpractice claims as primary data sources for perioperative death. As a result, prevalence data available for anesthesia-related mortality are approximate estimates as documented in Table 53-1.



Death attributable to anesthesia is rare.9 Anesthesia has evolved significantly regarding drug efficacy, equipment safety, and operative/procedural setting. Over 60% of surgical procedures are now performed in an ambulatory setting. Procedures associated with greater perioperative risk are increasingly being performed on an outpatient basis, and the use of regional techniques has increased.10 Emerging claim areas in which an increase has occurred over the years include regional anesthesia (16% of all claims), chronic pain management (18% of all claims), and acute pain (9% of all claims).6 By contrast, claims related specifically to surgical anesthesia have declined from 80% during the 1980s to 65% as compared with all anesthesia malpractice claims since 2000.6


The American Society of Anesthesiologists (ASA) classifies the patient’s physical status related to incidence of mortality on a scale of 1 to 5 based on comorbid conditions, 1 being the healthiest individual with no comorbidities and 5 being the individual that will likely die if surgery is not performed within 24 hours. The most current incidence of anesthesia mortality in a patient with an ASA physical status of 1 is 0.04 per 10,000 (0.0004%) anesthetics. Patients with comorbid conditions have higher risk. For example, an ASA physical status 2 risk is 0.5 per 10,000 (0.005%) anesthetics, an ASA physical status 3 risk is 2.7 per 10,000 (0.027%) anesthetics, and an ASA physical status 4 risk is 5.5 per 10,000 (0.055%) anesthetics.9 Death still remains the leading outcome in the ASA Closed Claims Project Database representing 26% of the most common complications from 1990 to 2007. The most common events leading to injury in anesthesia claims included regional blocks (20% of claims), respiratory (17% of claims), cardiovascular events (13% of claims), and equipment problems (10% of claims)6,8 (Box 53-1).



BOX 53-1   Complications of Anesthesia Identified by ASA Closed Claims Database




ASA, American Society of Anesthetists.


From Metzner J, et al. Closed claims’ analysis. Best Pract Res Clin Anaesthesiol. 2011;25:263-276.



Morbidity in Anesthesia


The term morbidity is indicative of disease, incorporating any complication, excluding death occurring during the perioperative period (Box 53-2). The incidence of adverse outcomes with minor morbidity is quite high (18%-22%). For example, hoarseness has been cited to occur in 14% to 50% of patients and may accompany a traumatic lesion in the larynx or hypopharyx in 6.3% of patients. Drug errors (0.1%), equipment malfunction (0.23%), postoperative nausea and vomiting (PONV) (10%-79%), accidental dural perforation (0.5-0.6%) are all fairly common anesthesia-related morbidities. Therefore, if morbidity is included in the definition of harm caused by anesthesia and linked to anesthesia safety within the framework of six sigma, then anesthesia remains far from being 99.99966% free of defects (Figure 53-1).4



BOX 53-2   Morbidity Classification




From Haller G, Laroche T, Clergue F. Morbidity in anaesthesia: today and tomorrow. Best Pract Res Clin Anaesthesiol. 2011;25(2):123-132.



Anesthesia risk remains even today in several areas including perioperative airway control during general anesthesia, perioperative management of hemorrhage, and circulatory perturbations associated with regional anesthesia. Human error contribution to morbidity is a significant concern identified in 51% to 77% of anesthesia-related deaths.4,9 It is difficult to quantify human error related to morbidity, and more research should be conducted in this area.


Teamwork and communication represent another cause of adverse outcomes contributing to 43% to 65% of sentinel events occurring in the operating room (e.g., wrong side/site, transfusion error). Communication breakdown (oral 36%, written 20%) and absence of help (44% of failures) when needed also contribute to morbidity.4


Anesthetic complications are the seventh leading cause of pregnancy-related mortality in the United States, accounting for 1.6% of all pregnancy-related deaths. An 18-year retrospective study of maternal mortality was conducted in the state of Michigan, where all pregnancy-associated deaths within 1 year of the termination of pregnancy for any cause were reviewed. Eight anesthesia-related and seven anesthesia-contributing maternal deaths were cited, and the pattern of deaths illustrates three key points. First, all anesthesia-related deaths from airway obstruction or hypoventilation took place during emergence and recovery, not during induction of general anesthesia. Second, system errors contributed to the majority of deaths, for example, lapses in standard postoperative monitoring, missed diagnoses (e.g., cardiomyopathy, ischemic heart disease, sleep apnea). Third, obesity and African-American race are important risk factors for anesthesia-related maternal mortality.11


Future morbidity/mortality issues will likely include more acute and chronic pain issues, regional anesthesia, issues related to oversedation, and management of the difficult airway. Analysis of these rare events is imperative, and can improve practice and ultimately patient safety. According to the Anesthesia Patient Safety Foundation (APSF), anesthesia-related mortality does not directly reflect patient safety during anesthesia. No patient should be harmed during anesthesia, but when a critical event does occur resulting in morbidity, the incident should be explored together with anesthesia-related mortality in order to assess the true level of patient safety during anesthesia.12



Patient Factors and Postoperative Mortality in Patients Over 70 Years


The population of older patients is growing in number, and increasingly these patients require surgery and anesthesia. Preventing, detecting, and managing morbidity and mortality is the greatest challenge facing anesthesia providers. Several large studies using worldwide databases have recently been published with an attempt to identify patient risk factors that could predict postoperative mortality. The most important resource available to date related to exploring complications and mortality after surgery is the National Surgical Quality Improvement Program (NSQIP) database in the United States. The NSQIP was established in the early 1990s as part of the U.S. Veterans’ Administration Health System and is now run by the American College of Surgeons, containing data on millions of surgical patients. The database has been associated with hundreds of publications centered on perioperative risk.13


One such study from the NSQIP database extracted data on 25,000 patients aged 80 years or more and 550,000 patients aged less than 80 years who had noncardiac surgery under general, spinal, or epidural anesthesia. In the cohort over 80 years of age, the top five variables associated with 30-day mortality were (1) ASA physical status, (2) preoperative plasma albumin concentration, (3) emergency surgery, (4) preoperative functional status, and (5) preoperative renal impairment.13,14


The Australian and New Zealand College of Anaesthetists (ANZCA) Trials Group recently published the REASON study (Research into Elderly patient Anaesthesia and Surgery Outcome Numbers), which was a prospective observational study of 4100 patients in 23 hospitals.14,15 Patients 70 years and older undergoing noncardiac surgery and expected to stay at least one night in the hospital were included. The major findings of this study were that 1 in 20 patients (5%) died within 30 days of surgery, and one in 5 (20%) had at least one major complication within 5 days of surgery. Four preoperative factors emerged predicting postoperative mortality similar to the results of the NSQIP database study: age, ASA physical status, albumin, and those patients who had an accident and needed emergency surgery were at increased risk. A useful statistic from the REASON study is that patients aged 70 years who are an ASA physical status 1 or 2 have a 30-day mortality of 1% for inpatient surgery. Patients 80 to 89 years had an odds ratio for 30-day mortality of 2.1, meaning this age group was twice as likely to die as compared with healthy patients 10 years younger. Additionally, those patients who were 90 years of age had an odds ratio for 30-day mortality of 4.0 or were 4 times as likely to have postoperative mortality as compared with healthy patients in their 70s (Table 53-2). The most important postoperative complications were systemic inflammation, acute renal impairment, and unplanned critical care admission.14,15



The National Confidential Enquiry into Patient Outcome and Death database in the United Kingdom provides reports on aspects of patient care and safety. A 2010 report explored remedial factors in the processes of care of patients aged 80 years and older who died within 30 days of a surgical procedure. Out of 1120 patients, 85% had an ASA physical classification of 3 or 4, most having nonelective surgery. Only one third of these patients who died had acceptable perioperative care.15 The authors concluded that the impact of comorbid conditions upon the frailty of a patient is underappreciated, and that increased vigilance in this patient population is warranted.


Until recently the risk of surgery, with accompanying anesthesia, was viewed as the prime determinant of mortality. However, NSQIP data extracted from 8500 patients concluded that after accounting for age, ASA status, albumin, and emergency surgery complexity are important in about 5% of cases.15 This reinforces the fact that surgery itself is safe, and patient factors are more important than operative procedure factors.


One emerging area in the care of older patients is the attempt to define and quantify frailty and risk of postoperative complications. Five domains of frailty have been described as depicted in Box 53-3. They include age, sex, comorbidities, physical status, and type of surgeries. Patients with 2 or 3 domains were considered to have intermediate frailty, and those having 4 to 5 domains were classified as frail. The odds ratio was 2.0 for postoperative complications in those who were considered to have intermediate frailty and 2.5 for frail patients.16



BOX 53-3   Domains of Frailty Measurements




From Makary MA, et al. Frailty as a predictor of surgical outcomes in older patients. J American Coll Surg. 2010;210(6):901-908.


While age has often been the focus of perioperative concern, comorbidity, quantified with ASA physical status, is probably more important. Frailty is the new addition to this paradigm. Risk assessment should begin with patient factors that are more strongly associated with outcome than type of operation. Preoperative albumin should be measured regularly in patients over 70 years of age.



Postoperative Cognitive Dysfunction


Postoperative cognitive changes after anesthesia have been reported in both the elderly for over a century and more recently in children displaying behavioral and developmental disorders after anesthesia.17 It has been postulated that anesthetic agents can produce neurotoxic effects leading to postoperative neurologic, developmental, and behavioral complications. Postoperative cognitive problems can be categorized as postoperative cognitive dysfunction (POCD), delirium, dementia, confusion, learning, and memory problems.



Elderly Undergoing Noncardiac Surgery


The two most common postoperative cognitive disorders in the elderly are delirium and POCD and can be difficult to diagnose. A comparison of these two disorders can be found in Table 53-3. Delirium is defined as a disturbance of consciousness that is accompanied by a change in cognition that cannot be attributed to a preexisting psychological state. Presentation of postoperative delirium is variable, and patients may exhibit hyper or hypoactive cognitive or motor states. Postoperative delirium usually occurs during the first postoperative days as an acute, fluctuating loss of orientation and impairment of attention and memory. The incidence of delirium is approximately 20% in hospitalized elderly patients, and 80% in sedated intensive care unit (ICU) patients. Delirium is independently associated with increased hospital stay and mortality. Age and preexisting disease are important risk factors, in addition to medication side effects, electrolyte or fluid defects, and withdrawal symptoms.17 Delirium research has focused on identification and treatment of risk factors prior to surgery. Factors associated with an increased postoperative delirium include advancing age, sensory deprivation (visual or hearing impairment), sleep deprivation, social isolation, physical restraint, use of bladder catheter, polypharmacy, psychoactive drugs, comorbidities, severe illness, cognitive impairment, hyper-/hypothermia, dehydration, malnutrition, and low serum albumin.18



Recent randomized controlled trials suggest that pain management and depth of general anesthesia are important modifiable factors for postoperative delirium after hip fracture surgery. Regional anesthesia with light propofol sedation compared with deep sedation was associated with a 50% decrease in postoperative delirium.19 Another recent study reported a 35% reduction in postoperative delirium after hip arthroplasty using a multifactorial approach. Perioperative interventions consisted of supplemental oxygen, systolic blood pressure greater than 90 mmHg, transfusion for hemoglobin less than 10 g/dL, adequate pain relief, intravenous fluid supplementation, normothermia, avoidance of polypharmacy, spinal anesthesia, propofol sedation, and use of paracetamol as well as opioid as needed.20 A Cochrane review concluded that regional anesthesia has a slight benefit over general anesthesia in reducing acute postoperative confusion after hip arthroplasty, but could not find a difference regarding mortality or other outcomes.21


POCD presents as a subtle deterioration of memory, concentration, and information processing distinct from delirium and dementia and is not a formal psychiatric diagnosis. Neuropsychologic testing is necessary for detection and must show that an individual has new onset of deficits in at least 2 areas of cognitive function lasting for a period of at least 2 weeks, and diagnosis is made when all other neurocognitive disorders can be ruled out. These diagnostic criteria make it impossible to accurately identify POCD during hospital stay, and symptoms can persist for weeks or months postoperatively.


One of the first large prospective studies describing postoperative cognitive decline after noncardiac surgery described an incidence of 25% at 1 week and 10% at 3 months after surgery. Advancing age was the only significant predictor for POCD at 3 months after surgery. Other similarly designed studies report POCD in up to 30% to 40% of adult patients of all ages at hospital discharge.17


General anesthesia has been implicated as the cause of postoperative cognitive problems. However, two large recent prospective studies demonstrated that type of anesthesia did not impact long-term cognitive outcome. A study comparing coronary angiography with light sedation, total hip arthroplasty with general anesthesia, and coronary artery bypass graft surgery under general anesthesia found a 16% to 17% incidence of POCD at 3 months in all three groups. Therefore, POCD may be independent of the type of anesthesia and surgical procedure.22


The concept of cerebral oxygen reserve offers one hypothesis regarding the significant differences in the degree of cognitive symptoms. Patients with preoperative vascular risk factors may be at greater risk for POCD. Several other etiologies have been proposed, including brain hypoxia caused by arterial hypoxemia or low flow, residual concentrations of general anesthetics such as benzodiazepines, or long-lasting effects of general anesthetics on cholinergic or glutaminergic neurotransmission, as well as psychological factors related to illness and environment during hospitalization.17



Elderly Undergoing Cardiac Surgery


The incidence of overall mortality after coronary artery bypass grafting has continued to decline; however, delirium and POCD remain a major concern in patients undergoing cardiac procedures, with an incidence ranging from 30% to 80%.23 It has been assumed that the use of extracorporeal cardiopulmonary bypass was the primary culprit; however, large prospective randomized studies comparing on-pump versus off-pump bypass techniques have not shown any significant reduction in the incidence of postoperative neurologic injury.24–26 The etiologic explanation could still involve the increased amount of atheromatous plaques and vascular disease in these patients, but this has yet to be clarified. Therefore, efforts to reduce incidence of postoperative neurologic injury have shifted focus towards patient risk factors (e.g., degree of aortic atherosclerosis, carotid arteries, and brain involvement).23



Pediatric Postoperative Cognitive Development Dysfunction


A great deal of concern has recently arisen regarding the safety of anesthesia in the pediatric population. Anesthetic agents have been implicated in pediatric developmental delays that have undergone prolonged procedures and/or multiple procedures (Figure 53-2).27 A growing body of evidence in animals suggests that under certain circumstances, anesthetic drugs could adversely affect neurologic, cognitive, and social development of neonates and young children.27,28



Exposure to certain anesthetic agents during sensitive periods of brain development in animal studies has been postulated to result in widespread neuronal apoptosis and functional deficits later in development. So far N-methyl-d-aspartate (NMDA) receptor antagonists and γ-aminobutyric acid (GABA) agonists have been implicated. However, no safe doses of these agents or safe duration of administration of these agents have been defined.28,29 For example, 5-day-old non-human primates exposed to ketamine for either 9 or 24 hours experienced neuroapoptosis. A similar neurologic damaging effect was observed in the fetuses of pregnant rhesus monkeys (third trimester) exposed to ketamine for 24 hours. No effect was seen when ketamine exposure duration was 3 hours. Neuroapoptosis also has been demonstrated in primates given isoflurane on postnatal day 6.28 The Food and Drug Administration (FDA) and others are currently conducting more studies to address the neurocognitive and neurobehavioral aspects of anesthetic-induced apoptosis.


Studies in children have attempted to assess effects of anesthetics on the developing human brain. A retrospective cohort analysis followed a birth cohort of 383 children who underwent inguinal hernia repair during the first 3 years of life and compared them with 5050 children in a control sample who had undergone no hernia repair before the age of 3 years. The children who underwent hernia repair were twice as likely as those who did not to have a developmental delay or behavioral disorder.28 Another recent study retrospectively examined children (younger than 4 years) who were exposed to a single anesthetic (n = 449), two anesthetics (n = 100), or more (n = 44) related to the development of learning disabilities. No increased risk of learning disabilities was found with a single anesthetic. However, significant increased risk of learning disabilities was associated with two or more anesthetics and also increased with greater cumulative exposure to anesthesia.29 It appears that windows of anesthetic vulnerability exist that are dependent on the exposure time, amount, and type of anesthesia. However, no definitive conclusions can be drawn on the basis of these nonrandomized studies in humans because of the substantial potential for confounding and bias. Interpretation is difficult due to the retrospective nature of the studies, lack of precise information in terms of age, agent, duration, and dose of anesthetics, specific agents used, variable outcome end-points used, and the method outcomes that were assessed.27 Although withholding anesthesia in children who need surgery is unreasonable, obtaining more information about safe use is imperative. If anesthetic agents are found to affect the developing brain, strategies for mitigating and managing such risks can be implemented.27–29



Cardiopulmonary Complications



Intraoperative Cardiac Arrest


Currently, cardiac arrest during anesthesia is usually a concomitant and not a causative factor. Incidence of intraoperative cardiac arrest has been cited as 0.2 to 1.1 per 10,000 adults and 1.4 to 2.9 per 10,000 children.30,31 Cardiac arrest during neuraxial anesthesia is less frequent compared with general anesthesia, with an incidence of 0.04 to 1.8 per 10,000 anesthetics. Etiologic factors can be grouped into categories: preoperative complications (65%), surgical procedures (24%), intraoperative pathologic events (9%), and those attributable to anesthetic management (2%).31 Excessive surgical bleeding has been identified in 70% of surgical procedure-related deaths, and major causes of intraoperative pathologic events (e.g., myocardial ischemia, pulmonary embolism, and severe dysrhythmias). Fifty-percent of anesthetic management–related events were caused by airway or ventilatory problems, followed by medication errors and infusion/transfusion mishaps. Perioperative cardiac arrest is multifactorial in origin including factors such as patient comorbidities, inadequate risk estimation, inappropriate anesthetic management, and human error or misjudgment.30,31



Sudden Cardiac Arrest


Sudden cardiac arrest (SCA) is a leading cause of death in the United States, accounting for an estimated 325,000 deaths each year. Approximately 6 cases per 100,000 individuals have been reported.32 Ninety-five percent of victims die before ever reaching emergency assistance. The most common underlying substrate of sudden cardiac arrest is ischemia and/or left ventricular dysfunction (Table 53-4).33 Hypertrophic cardiomyopathy is the most common underlying cause of sudden cardiac death in young athletes.32 However, there are also patients with preserved left ventricular function who are at risk for sudden cardiac arrest. Many of these individuals are walking around with long QT syndrome (LQTS).34 Long QT syndrome has gained increased attention because of young athletes collapsing unexpectedly in sudden cardiac arrest. Long QT syndrome is an arrhythmogenic inherited or acquired cardiovascular disorder, with a prevalence of approximately 1 per 2500 to 10,000, causing sudden death as a result of episodes of syncope, seizures, and ventricular tachycardia. Only about 60% of patients are symptomatic at the time of diagnosis. Induction of general anesthesia has provoked LQTS without any prior clinical diagnosis or preoperative abnormal clinical findings.35 Sudden sympathetic stimulation during intubation may be a cause or it could be QTc (interval corrected for heart rate) prolongation, as well as drugs that have positive adrenergic properties (e.g., ketamine, pancuronium). Careful anesthetic management should include treatment with beta-blockers preoperatively. Heart rate should be maintained below 130 beats/minute. It is recommended to avoid any pharmacologic agents that have the potential to further prolong the QT interval (Table 53-5).36 Episodes of torsades de pointes may be short lived and self-terminating, but treatment with magnesium sulfate is considered the treatment of choice. Temporary pacing is also an effective method for controlling torsades de pointes (Figure 53-3).35,37



TABLE 53-4


Causes of Sudden Cardiac Death







































Underlying Heart Disease Incidence Description
Ischemic heart disease Greater than 50% luminal narrowing
Less than 20 yr, 0%
20-29 yr, 24%
30-40 yr, 58%		 Atherosclerotic coronary artery disease, generally with normal cardiac function
Sudden arrhythmic death syndrome Brugada syndrome 5:10,000 (0.05%)
Long QT syndrome 1:2500 (0.04%)
Short QT syndrome
Catecholaminergic polymorphic VT 1: 10,000 (0.01%)
Wolff-Parkinson-White syndrome 0.9%-3%		 Brugada syndrome—hereditary channelopathy with right ventricular conduction delay and ST elevation in right precordial leads (dome or cove-like) associated with incomplete or complete right bundle-branch block and ultimately VF
Long QT syndrome—channelopathy with QT interval (greater than 480 ms)
Short QT syndrome—channelopathy with QT interval (less than 340 ms)
Catecholaminergic polymorphic VT—genetically mediated, cardiac channelopathy induced by exercise or emotional stress with structurally normal hearts
Wolff-Parkinson-White syndrome—preexcitation syndrome with an accessory pathway (Bundle of Kent) causing atrioventricular reentrant tachycardia and/or VF with structurally normal hearts; shortened PR, delta waves, and widened QRS may be present
Hypertrophic cardiomyopathy (HCM) 1:500 (0.2%) of general population
36% of all sudden cardiac deaths (additional 10% of cases have unexplained increase in cardiac mass not meeting full criteria for HCM		 Inherited disease characterized by myocyte disarray, asymmetric hypertrophy of left ventricle (typically at the septum), occasional LV outflow tract obstruction, and predisposition for unstable ventricular arrhythmias
Arrhythmogenic right ventricular cardiomyopathy 1:5000 (0.02%) general population Right ventricular wall-thinning and fibrofatty tissue infiltration
Congenital right ventricular cardiomyopathy 18% congenitally abnormal coronary arteries
12% anomalous coronary artery origins and hypoplastic anatomy		 Also called arrhythmogenic right ventricular dysplasia (ARVD); rare form of cardiomyopathy in which the heart muscle of the right ventricle is replaced by fat and/or fibrous tissue
Commotio cordis 5% (nonspecific causes)
19.9% (athletic injury)		 Blunt chest wall impact
Myocarditis Less than 5% Myocardial inflammation
Aortic disorder 3%-8% Thoracic dissection/rupture

VT, Ventricular tachycardia; VF, ventricular fibrillation; LV, left ventricle.


Adapted from Cross BJ, Estes M, Link MS. Sudden cardiac death in young athletes and nonathletes. Curr Opin Crit Care. 2011;17(4):328-334; Heiner JD, Bullard-Berent JH, Inbar S. Deadly proposal, a case of catecholaminergic polymorphic ventricular tachycardia. Pediatr Emerg Care. 2011;27(11):1065-1068.




Perioperative episodes of sudden cardiac arrest in the pediatric population sparked the formation of the Pediatric Perioperative Cardiac Arrest Registry in 1994 to study the causes and outcomes from perioperative cardiac arrests in anesthetized children. Results from a recent examination of arrests from 1998 to 2004 indicate that cardiovascular causes of arrest accounted for the highest proportion of arrests (41%); among these the most common identifiable single cause was hypovolemia related to underestimation of blood loss and inadequate peripheral IV access (Figure 53-4).38 Cardiac arrests due to medication errors were most common during the mid-1990s; this statistic has dropped significantly during more recent years. One explanation for this is a decline in the incidence of cardiac depression from decreased use of halothane.38




Myocardial Infarction


The Perioperative Ischemic Evaluation (POISE) trial data using surgical data from 56 countries suggests that perioperative myocardial infarction (MI) is the most common cardiovascular complication after noncardiac surgery, with an incidence of 5% in patients 45 years or older with cardiovascular risk factors.39 Patients who suffer a perioperative MI have a 30-day mortality of between 11.6% and 21.6%.40 Over 200 million noncardiac surgical procedures are performed annually worldwide, which equates to 10 million perioperative myocardial infarctions and more than 1.1 million deaths. This is a significant public burden considering that perioperative MIs are commonly undiagnosed and undertreated.39


Characteristics and short-term prognosis of perioperative MI have evolved over the past two decades. Fewer patients with nonoperative MI have ST-segment elevation, and more patients have non–ST segment elevation. Short-term mortality is decreasing. A large cohort study using POISE data extracted from over 8000 patients reported that most MIs occur within 48 hours of surgery (74.1%); 65.5% were asymptomatic.40 Independent predictors of perioperative MI from this cohort are depicted in Table 53-6.


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May 31, 2016 | Posted by in ANESTHESIA | Comments Off on Anesthesia Complications

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