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Background: Much is still unknown about the actual incidence of anesthesia-related cardiac arrest in the United States., Methods: The authors identified all of the cases of cardiac arrest from their quality improvement database from 1999 to 2009 and submitted them for review by an independent study commission to give them the best estimate of anesthesia-related cardiac arrest at their institution. One hundred sixty perioperative cardiac arrests within 24 h of surgery were identified from an anesthesia database of 217,365 anesthetics. An independent study commission reviewed all case abstracts to determine which cardiac arrests were anesthesia-attributable or anesthesia-contributory. Anesthesia-attributable cardiac arrests were those cases in which anesthesia was determined to be the primary cause of cardiac arrest. Anesthesia-contributory cardiac arrests were those cases where anesthesia was determined to have contributed to the cardiac arrest., Results: Fourteen cardiac arrests were anesthesia-attributable, resulting in an incidence of 0.6 per 10,000 anesthetics (95% CI, 0.4 to 1.1). Twenty-three cardiac arrests were found to be anesthesia-contributory resulting in an incidence of 1.1 per 10,000 anesthetics (95% CI, 0.7 to 1.6). Sixty-four percent of anesthesia-attributable cardiac arrests were caused by airway complications that occurred primarily with induction, emergence, or in the postanesthesia care unit, and mortality was 29%. Anesthesia-contributory cardiac arrest occurred during all phases of the anesthesia, and mortality was 70%., Conclusion: As judged by an independent study commission, anesthesia-related cardiac arrest occurred in 37 of 160 cardiac arrests within the 24-h perioperative period.

Background: Delay in defibrillation (more than 2 min) is associated with worse survival in patients with a cardiac arrest because of ventricular fibrillation or pulseless ventricular tachycardia in intensive care units and inpatient wards., Methods: We tested the relationship between delayed defibrillation and survival from intraoperative or periprocedural cardiac arrest, adjusting for baseline patient characteristics. The analysis was based on data from 865 patients who had intraoperative or periprocedural cardiac arrest caused by ventricular fibrillation or pulseless ventricular tachycardia in 259 hospitals participating in the National Registry of Cardiopulmonary Resuscitation., Results: The median time to defibrillation was less than 1 min (interquartile range, <1 to 1 min). Delays in defibrillation occurred in 119 patients (13.8%). Characteristics associated with delayed defibrillation included pulseless ventricular tachycardia and noncardiac admitting diagnosis. The association between delayed defibrillation and survival to hospital discharge differed for periprocedural and intraoperative cardiac arrests (P value for interaction = 0.003). For patients arresting outside the operating room, delayed defibrillation was associated with a lower probability of surviving to hospital discharge (31.6% vs. 62.1%, adjusted odds ratio 0.49; 95% CI 0.27, 0.88; P = 0.018). In contrast, delayed defibrillation was not associated with survival for cardiac arrests in the operating room (46.8% vs. 39.6%, adjusted odds ratio 1.23, 95% CI 0.70, 2.19, P = 0.47)., Conclusions: Delays in defibrillation occurred in one of seven cardiac arrests in the intraoperative and periprocedural arenas. Although delayed defibrillation was associated with lower rates of survival after cardiac arrests in periprocedural areas, there was no association with survival for cardiac arrests in the operating room.

Background: Despite decreasing cardiac events, perioperative beta-blockade also increases perioperative stroke and mortality. Major bleeding and/or hypotension are independently associated with these outcomes. To investigate the hypothesis that beta-blockade limits the cardiac reserve to compensate for acute surgical anemia, the authors examined the relationship between cardiac events and acute surgical anemia in patients with and without beta-blockade., Methods: The records of all noncardiac, nontransplant surgical patients between March 2005 and June 2006 were retrospectively retrieved. The primary outcome was a composite that comprised myocardial infarction, nonfatal cardiac arrest, and in-hospital mortality (major adverse cardiac event). The lowest recorded hemoglobin in the first 3 days defined nadir hemoglobin. Propensity scores estimating the probability of receiving a perioperative beta-blocker were used to match (1:1) patients who did or did not receive beta-blockers postoperatively. The relationship between nadir hemoglobin and major adverse cardiac event was then assessed., Results: This analysis identified 4,387 patients in whom nadir hemoglobin could be calculated; 1,153 (26%) patients were administered beta-blockers within the first 24 h of surgery. Propensity scores created 827 matched pairs that were well balanced for all measured confounders. Major adverse cardiac event occurred in 54 (6.5%) beta-blocked patients and in 25 (3.0%) beta-blocker naive patients (relative risk 2.38; 95% CI 1.43-3.96; P = 0.0009). The restricted cubic spline relationship demonstrated that this difference was restricted to those patients in whom the hemoglobin decrease exceeded 35% of the baseline value., Conclusions: beta-Blocked patients do not seem to tolerate surgical anemia when compared with patients who are naive to beta-blockers. Prospective studies are required to validate these findings.

Background: The authors determined associated cardiac arrest and death rates in cases from Canada and the United States as reported to The North American Malignant Hyperthermia (MH) Registry and analyzed factors associated with a higher risk of poor outcomes., Methods: The authors searched the database for AMRA (adverse metabolic/musculoskeletal reaction to anesthesia) reports with inclusion criteria as follows: event date between January 1, 1987, and December 31, 2006; "very likely" or "almost certain" MH as ranked by MH Clinical Grading Scale; location in Canada or the United States; and one or more anesthetic agents given. The exclusion criterion was a pathologic condition other than MH independently judged by the authors. Severe MH outcomes were analyzed as regards clinical history and presentation, using Wilcoxon rank sum tests for continuous variables and Pearson exact chi-square tests for categorical variables. A Bonferroni correction adjusted for multiple comparisons., Results: Of 291 events, 8 (2.7%) resulted in cardiac arrests and 4 (1.4%) resulted in death. The median age in cases of cardiac arrest/death was 20 yr (range, 2-31 yr). Associated factors were muscular build (odds ratio, 18.7; P = 0.0016) and disseminated intravascular coagulation (odds ratio, 49.7; P < 0.0001). Increased risk of cardiac arrest/death was related to a longer time period between anesthetic induction and maximum end-tidal carbon dioxide (216 vs. 87 min; P = 0.003). Unrelated factors included patient or family history, anesthetic management, and the MH episode., Conclusions: Modern US anesthetic practice did not prevent MH-associated cardiac arrest and death in predominantly young, healthy patients undergoing low- to intermediate-risk surgical procedures.

Background: The objective of this study was to determine the incidence and outcome of perioperative cardiac arrest (CA) in children younger than 18 yr undergoing anesthesia for noncardiac and cardiac procedures at a tertiary care center., Methods: After institutional review board approval (Mayo Clinic, Rochester, Minnesota), all patients younger than 18 yr who had perioperative CA between November 1, 1988, and June 30, 2005, were identified. Perioperative CA was defined as a need for cardiopulmonary resuscitation or death during anesthesia care. A cardiac procedure was defined as a surgical procedure involving the heart or great vessels requiring an incision., Results: A total of 92,881 anesthetics were administered during the study period, of which 4,242 (5%) were for the repair of congenital heart malformations. The incidence of perioperative CA during noncardiac procedures was 2.9 per 10,000, and the incidence during cardiac procedures was 127 per 10,000. The incidence of perioperative CA attributable to anesthesia was 0.65 per 10,000 anesthetics, representing 7.5% of the 80 perioperative CAs. Both CA incidence and mortality were highest among neonates (0-30 days of life) undergoing cardiac procedures (incidence: 435 per 10,000; mortality: 389 per 10,000). Regardless of procedure type, most patients who experienced perioperative CA (88%) had congenital heart disease., Conclusion: The majority of perioperative CAs were caused by factors not attributed to anesthesia, in distinction to some recent reports. The incidence of perioperative CA is many-fold higher in children undergoing cardiac procedures, suggesting that definition of case mix is necessary to accurately interpret epidemiologic studies of perioperative CA in children.

Background: The authors determined the incidence of cardiac arrest and predictors of survival following perioperative cardiac arrest in a large population of patients at a tertiary referral center., Methods: Medical records of patients who experienced cardiac arrest in the perioperative period surrounding noncardiac surgery between January 1, 1990, and December 31, 2000, were reviewed. Logistic regression identified characteristics associated with immediate (>or= 1 h) and hospital survival, with P

Background: Deep hypothermic circulatory arrest (DHCA), as used in infant heart surgery, carries a risk of brain injury. In a piglet DHCA model, neocortical neurons appear to undergo apoptotic death. Caspases, cytochrome c, tumor necrosis factor (TNF), and Fas play a role in apoptosis in many ischemic models. This study examined the expression of these factors in a DHCA piglet model., Methods: Thirty-nine anesthetized piglets were studied. After cardiopulmonary bypass (CPB) cooling of the brain temperature to 19 degrees C, DHCA was induced for 90 min, followed by CPB rewarming. After separation from CPB, piglets were killed at 1, 4, 8, 24, and 72 h and 1 week. Caspase-8 and -3 activity, and concentrations of TNF-alpha, Fas, Fas-ligand, cytochrome c, and adenosine triphosphate (ATP) were measured in the neocortex by enzymatic assay and Western blot analysis. Caspase-8 and -3 activity and cell death were examined histologically. Significance was set at P < 0.05., Results: In neocortex, damaged neurons were not observed in control (no CPB), rarely observed in CPB (no DHCA), and rarely observed in the DHCA 1-h, 4-h, and 1-week reperfusion groups. However, they were seen frequently in the DHCA 8-, 24-, and 72-h reperfusion groups. Although neuronal death was widespread 8-72 h after DHCA, cortical ATP concentrations remained unchanged from control. Both caspase-3 and -8 activities were significantly increased at 8 h after DHCA, and caspase-3 concentration remained elevated for as long as 72 h. Caspase-3 and -8 activity was also observed in damaged neocortical neurons. Cytosolic cytochrome c and Fas were significantly expressed at 1 h and 4 h after DHCA, respectively. Fas-ligand and TNF-alpha were not observed in any group., Conclusion: After DHCA, induction of apoptosis in the neocortex occurs within a few hours of reperfusion and continues for several days. Increased Fas, cytochrome c, and caspase concentrations, coupled with normal brain ATP concentrations and apoptotic histologic appearance, are consistent with the occurrence of apoptotic cell death.

Background: Cardiopulmonary bypass (CPB) and deep hypothermic circulatory arrest (DHCA), as used for infant heart surgery, carry a risk of ischemic neurologic injury. Volatile anesthetics have neuroprotective properties against both global and focal ischemia at normothermia. The authors examined the hemodynamic and neuroprotective effects of desflurane in a piglet CPB-DHCA model., Methods: Twenty piglets aged 5-10 days received a desflurane- (6-9% expired) or fentanyl-based anesthetic before and during CPB (before and after DHCA). DHCA lasted 90 min at 19 degrees C brain. Cardiovascular variables (heart rate, arterial pressure, blood gases, glucose, brain temperature) were monitored. On postoperative day 2, neurologic and histologic outcomes were determined., Results: Cardiovascular variables before, during, and after CPB were physiologically similar between groups. The desflurane group had better neurologic performance (P = 0.023) and greater postoperative weight gain (P = 0.04) than the fentanyl group. In neocortex, the desflurane group had less tissue damage (P = 0.0015) and fewer dead neurons (P = 0.0015) than the fentanyl group. Hippocampal tissue damage was less in the desflurane group (P = 0.05), but overall, neuronal cell counts in the CA1 sector of the right hippocampus were similar to those in the fentanyl group., Conclusions: Desflurane-based anesthesia yields hemodynamics during CPB with DHCA that are similar to those with fentanyl-based anesthesia. However, desflurane-based anesthesia improves neurologic and histologic outcomes of CPB-DHCA in comparison with outcomes with fentanyl-based anesthesia.

Background: The Pediatric Perioperative Cardiac Arrest (POCA) Registry was formed in 1994 in an attempt to determine the clinical factors and outcomes associated with cardiac arrest in anesthetized children., Methods: Institutions that provide anesthesia for children are voluntarily enrolled in the POCA Registry. A representative from each institution provides annual institutional demographic information and submits anonymously a standardized data form for each cardiac arrest (defined as the need for chest compressions or as death) in anesthetized children 18 yr of age or younger. Causes and factors associated with cardiac arrest are analyzed., Results: In the first 4 yr of the POCA Registry, 63 institutions enrolled and submitted 289 cases of cardiac arrest. Of these, 150 arrests were judged to be related to anesthesia. Cardiac arrest related to anesthesia had an incidence of 1.4 +/- 0.45 (mean +/- SD) per 10,000 instances of anesthesia and a mortality rate of 26%. Medication-related (37%) and cardiovascular (32%) causes of cardiac arrest were most common, together accounting for 69% of all arrests. Cardiovascular depression from halothane, alone or in combination with other drugs, was responsible for two thirds of all medication-related arrests. Thirty-three percent of the patients were American Society of Anesthesiologists physical status 1-2; in this group, 64% of arrests were medication-related, compared with 23% in American Society of Anesthesiologists physical status 3-5 patients (P < 0.01). Infants younger than 1 yr of age accounted for 55% of all anesthesia-related arrests. Multivariate analysis demonstrated two predictors of mortality: American Society of Anesthesiologists physical status 3-5 (odds ratio, 12.99; 95% confidence interval, 2.9-57.7), and emergency status (odds ratio, 3. 88; 95% confidence interval, 1.6-9.6)., Conclusions: Anesthesia-related cardiac arrest occurred most often in patients younger than 1 yr of age and in patients with severe underlying disease. Patients in the latter group, as well as patients having emergency surgery, were most likely to have a fatal outcome. The identification of medication-related problems as the most frequent cause of anesthesia-related cardiac arrest has important implications for preventive strategies.

Background: The incidence of perioperative bradyarrhythmias in patients with bifascicular or left bundle branch block (LBBB) and the influence of an additional first-degree atrioventricular (A-V) block has not been evaluated with 24-h Holter electrocardiographic monitoring. Therefore the authors assessed the rate of block progression and bradyarrhythmia in these patients., Methods: Patients (n = 106) with asymptomatic bifascicular block or LBBB with or without an additional first-degree A-V block scheduled for surgery under general or regional anesthesia were enrolled prospectively. Three patients were excluded. Of the 103 remaining, 56 had a normal P-R interval and 47 had a prolonged one. Holter monitoring (CM2, CM5) was applied to each patient just before induction of anesthesia and was performed for 24 h. The primary endpoint of the study was the occurrence of block progression. As secondary endpoints, bradycardias < 40 beats/min with hemodynamic compromise (systolic blood pressure < 90 mmHg) or asystoles > 5 s were defined., Results: Block progression to second-degree A-V block and consecutive cardiac arrest occurred in one case of LBBB without a prolonged P-R interval Severe bradyarrhythmias with hypotension developed in another eight patients: asystoles > 5 s occurred in two cases and six patients had bradycardias < 40/min. Pharmacotherapy was successful in these eight patients. There was no significant difference for severe bradyarrhythmias associated with hemodynamic compromise between patients with and without P-R prolongation (P = 1.00)., Conclusions: In patients with chronic bifascicular block or LBBB, perioperative progression to complete heart block is rare. However, the rate of bradyarrhythmias with hemodynamic compromise proved to be relevant. Because an additional first-degree A-V block did not increase the incidence of severe bradyarrhythmias and pharmacotherapy by itself was successful in nearly all cases, routine prophylactic insertion of a temporary pacemaker in such patients should be questioned.

Background: Serious complications related to regional anesthesia have previously been described primarily in case reports and retrospective surveys. The authors prospectively evaluated a multicenter series of regional anesthetics, using preplanned criteria to measure the incidence and characteristics of associated serious complications., Methods: Requests were sent to 4,927 French anesthesiologists in advance of a subsequent 5-month study period. Participating anesthesiologists were asked for detailed reports of serious complications occurring during or after regional anesthetics performed by them during the study interval. Details regarding each complication then were obtained via a second questionnaire., Results: The number of responding anesthesiolgists was 736. The number of regional anesthetics performed was 103,730, corresponding to 40,640 spinal anesthetics, 30,413 epidural anesthetics, 21,278 peripheral nerve blocks, and 11,229 intravenous regional anesthetics. Reports of 98 severe complications were received, with follow-up information being obtained for 97. In 89 cases, complications were attributed fully or partially to regional anesthesia. Thirty-two cardiac arrests, seven of which were fatal, occurred during the study. Of these, 26 occurred during spinal anesthesia, with 6 being fatal, 3 occurred during epidural anesthesia, and 3 more occurred during peripheral blocks. The higher incidence of cardiac arrest during spinal anesthesia (6.4 +/- 1.2 per 10,000 patients) compared with all other regional anesthesia (1.0 +/- 0.4 per 10,000 patients) was statistically significant (P < 0.05). Of 34 neurologic complications (radiculopathy, cauda equina syndrome, paraplegia), 21 were associated either with paresthesia during puncture (n = 19) or with pain during injection (n = 2), suggesting nerve trauma or intraneural injection. Twelve patients who had neurologic complications after spinal anesthetics had no paresthesia during needle placement and no pain on injection. Of these 12 patients (7 with radiculopathy and 5 with cauda equina syndrome), 9 received intrathecal hyperbaric lidocaine, 5%. The incidence of neurologic injury was significantly greater after spinal anesthesia (6 +/- 1 per 10,000 cases; P < 0.05) than after each of the other types of regional procedures (1.6 +/- 0.5 per 10,000 cases for the weighted average). Seizures attributed to elevated serum levels of local anesthetics occurred in 23 patients, but none suffered a cardiac arrest., Conclusions: (1) The incidence of cardiac arrest and neurologic injury related to regional anesthesia were very low, but both were more than three SDs greater after spinal anesthesia than after other regional procedures. (2) Two thirds of the patients with neurologic deficits had either a paresthesia during needle placement or pain on injection. (3) Seventy-five percent of the neurologic deficits after nontraumatic spinal anesthesia occurred in patients who had received hyperbaric lidocaine, 5%.

The purpose of this study was to compare the efficacy of standard cardiopulmonary resuscitation and cardiopulmonary resuscitation with interposed abdominal compression for restoration of spontaneous circulation in an asphyxial and fibrillatory arrest model. Twenty-eight pigs weighing 19-27 kg were randomly allocated to two arrest groups. Each of these two groups was then subdivided into a treatment group and a control group resulting in four groups of seven pigs each. In the control groups standard cardiopulmonary resuscitation was performed with a pneumatically driven chest compressor at a rate of 80 beats per min. The animals' lungs were ventilated at a respiratory rate of 20 breaths per min independently of chest compression. In the treatment group, in addition to standard cardiopulmonary resuscitation, manual interposed abdominal compression was applied at the midabdomen in the second half of the relaxation phase using a blood pressure cuff to measure and standardize the compressions. Following asphyxial cardiac arrest of 3 min, none of the seven animals could be resuscitated with standard cardiopulmonary resuscitation, whereas all seven animals could be resuscitated with interposed abdominal compression and standard cardiopulmonary resuscitation after 240 +/- 84 s. Following fibrillatory cardiac arrest of 4 min, none of the seven animals that received standard cardiopulmonary resuscitation and countershocks could be resuscitated. In the group that received standard cardiopulmonary resuscitation and interposed abdominal compression spontaneous circulation was achieved in all animals in 244 +/- 117 s. End-diastolic arteriovenous pressure difference, which correlates with coronary blood flow, was significantly higher with interposed abdominal compression during resuscitation from both forms of cardiac arrest. The results of our study indicate that cardiopulmonary resuscitation with interposed abdominal compression in the second half of the relaxation phase improves diastolic arteriovenous pressure difference and resuscitation success in comparison with that following standard cardiopulmonary resuscitation. The use of interposed abdominal compression during basic cardiac life support should be investigated further in patients.