Robert A. Caplan

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

RACTICE Guidelines are systematically developed recommendations that assist the practitioner and patient in making decisions about health care. These recommendations may be adopted, modified, or rejected according to clinical needs and constraints and are not intended to replace local institutional policies. In addition, Practice Guidelines developed by the American Society of Anesthesiologists (ASA) are not intended as standards or absolute requirements, and their use cannot guarantee any specific outcome. Practice Guidelines are subject to revision as warranted by the evolution of medical knowledge, technology, and practice. They provide basic recommendations that are supported by a synthesis and analysis of the current literature, expert and practitioner opinion, open-forum commentary, and clinical feasibility data. This document updates the “Practice Guidelines for Management of the Difficult Airway: An Updated Report by

Adverse respiratory events in anesthesia: a closed claims analysis.

Adverse outcomes associated with respiratory events constitute the single largest class of injury in the American Society of Anesthesiology Closed Claims Study (522 of 1541 cases; 34%). Death or brain damage occurred in 85% of cases. The median cost of settlement or jury award was +200,000. Most outcomes (72%) were considered preventable with better monitoring. Three mechanisms of injury accounted for three-fourths of the adverse respiratory events: inadequate ventilation (196; 38%), esophageal intubation (94; 18%), and difficult tracheal intubation (87; 17%). Inadequate ventilation was used to describe claims in which it was evident that insufficient gas exchange had produced the adverse outcome, but it was not possible to identify the exact cause. This group was characterized by the highest proportion of cases in which care was considered substandard (90%). The esophageal intubation group was notable for a recurring diagnostic failure: in 48% of cases where auscultation of breath sounds was performed and documented, this test led to the erroneous conclusion that the endotracheal tube was correctly located in the trachea. Claims for difficult tracheal intubation were distinguished by a comparatively small proportion of cases (36%) in which the outcome was considered preventable with better monitoring. A better understanding of respiratory risks may require investigative protocols that initiate data collection immediately upon the recognition of a critical incident or adverse outcome.

Management of the Difficult Airway

BACKGROUND The purpose of this study was to identify the patterns of liability associated with malpractice claims arising from management of the difficult airway. METHODS Using the American Society of Anesthesiologists Closed Claims database, the authors examined 179 claims for difficult airway management between 1985 and 1999 where a supplemental data collection tool was used and focused on airway management, outcomes, and the role of the 1993 Difficult Airway Guidelines in litigation. Chi-square tests and multiple logistic regression analysis compared risk factors for death or brain damage (death/BD) from two time periods: 1985-1992 and 1993-1999. RESULTS Difficult airway claims arose throughout the perioperative period: 67% upon induction, 15% during surgery, 12% at extubation, and 5% during recovery. Death/BD with induction of anesthesia decreased in 1993-1999 (35%) compared with 1985-1992 (62%; P < 0.05; odds ratio, 0.26; 95% confidence interval, 0.11-0.63; P = 0.003). In contrast, death/BD associated with other phases of anesthesia did not significantly change over the time periods. The odds of death/BD were increased by the development of an airway emergency (odds ratio, 14.98; 95% confidence interval, 6.37-35.27; P < 0.001). During airway emergencies, persistent intubation attempts were associated with death/BD (P < 0.05). Since 1993, the Airway Guidelines were used to defend care (8%) and criticize care (3%). CONCLUSIONS Death/BD in claims from difficult airway management associated with induction of anesthesia but not other phases of anesthesia decreased in 1993-1999 compared with 1985-1992. Development of additional management strategies for difficult airways encountered during maintenance, emergence, or recovery from anesthesia may improve patient safety.

Anesthesia-related cardiac arrest in children: initial findings of the Pediatric Perioperative Cardiac Arrest (POCA) Registry.

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.

Incidence and Risk Factors for Side Effects of Spinal Anesthesia

We prospectively studied 952 patients to identify the incidence of hypotension (systolic blood pressure less than 90 mmHg), bradycardia (heart rate less than 50 beats/min), nausea, vomiting, and dysrhythmia during spinal anesthesia. Historical, clinical, and physiologic data were correlated with the incidence of these side effects by univariate and multivariate analysis. Hypotension developed in 314 patients (33%), bradycardia in 125 (13%), nausea in 175 (18%), vomiting in 65 (7%), and dysrhythmia in 20 (2%). Variables conferring increased odds of developing hypotension include peak block height greater than or equal to T5 (odds ratio 3.8, P less than 0.001), age greater than or equal to 40 yr (2.5, P less than 0.001), baseline systolic blood pressure less than 120 mmHg (2.4, P less than 0.001), combination of spinal and general anesthesia (1.9, P = 0.01), spinal puncture at or above the L2-L3 interspace (1.8, P less than 0.001), and addition of phenylephrine to the local anesthetic (1.6, P = 0.02). Variables conferring increased odds of developing bradycardia include a baseline heart rate less than 60 beats/min (odds ratio 4.9, P less than 0.001), ASA physical status classification of 1 versus 3 or 4 (3.5, P less than 0.001), current therapy with beta-adrenergic blocking drugs (2.9, P less than 0.001), and peak block height greater than or equal to T5 (1.7, P = 0.02). Variables conferring increased odds of developing nausea or vomiting include addition of phenylephrine or epinephrine to the local anesthetic (3.0-6.3, P less than or equal to 0.003), peak block height greater than or equal to T5 (odds ratio 3.9, P less than 0.001), use of procaine (2.6-4.4, P less than or equal to 0.003), baseline heart rate greater than or equal to 60 beats/min (2.3, P = 0.03), history of carsickness (2.0, P = 0.01), and development of hypotension during spinal anesthesia (1.7, P = 0.009). Our results indicate that the incidence of side effects during spinal anesthesia may be reduced by 1) minimizing peak block height; 2) using plain solutions of local anesthetics; 3) performing the spinal puncture at or below the L3-L4 interspace; and 4) avoiding the use of procaine in the subarachnoid space.

Unexpected cardiac arrest during spinal anesthesia: a closed claims analysis of predisposing factors.

Fourteen cases of sudden cardiac arrest in healthy patients who received spinal anesthesia were discovered in a preliminary review of 900 closed insurance claims for major anesthetic mishaps. All patients were resuscitated from the intraoperative cardiac arrest, but six suffered such severe neurologic injury that they died in hospital. Of the eight survivors, only one exhibited sufficient neurologic recovery to allow independence in daily self-care. In view of the unexpected nature of the cardiac arrests, as well as the ultimate severity of injury, these cases were analyzed in detail to determine whether there were recurring patterns of management that may have contributed to the occurrence or outcome of these anesthetic mishaps. Two patterns were identified. The first was the intraoperative use of sufficient sedation to produce a comfortable-appearing, sleep-like state in which there was no spontaneous verbalization. Cyanosis frequently heralded the onset of cardiac arrest in patients exhibiting this degree of sedation, suggesting that unappreciated respiratory insufficiency may have played an important role. The second pattern appeared to be an inadequate appreciation of the interaction between sympathetic blockade during high spinal anesthesia and the mechanisms of cardiopulmonary resuscitation. Prompt augmentation of central venous filling through the use of a potent α-agonist and positional change might have improved organ perfusion, shortened the duration of cardiac arrest, and lessened the degree of neurologic damage.

Practice advisory for preanesthesia evaluation: an updated report by the American Society of Anesthesiologists Task Force on Preanesthesia Evaluation.

P RACTICE Advisories are systematically developed reports that are intended to assist decision-making in areas of patient care. Advisories provide a synthesis and analysis of expert opinion, clinical feasibility data, open forum commentary, and consensus surveys. Practice Advisories developed by the American Society of Anesthesiologists (ASA) are not intended as standards, guidelines, or absolute requirements, and their use cannot guarantee any specific outcome. They may be adopted, modified, or rejected according to clinical needs and constraints and are not intended to replace local institutional policies. Practice Advisories are not supported by scientific literature to the same degree as standards or guidelines because of the lack of sufficient numbers of adequately controlled studies. Practice Advisories are subject to periodic update or re-

Nerve injury associated with anesthesia.

The authors examined the American Society of Anesthesiologists Closed Claims Study database to define the role of nerve damage in the overall spectrum of anesthesia-related injury that leads to litigation. Of 1,541 claims reviewed, 227 (15%) were for anesthesia-related nerve injury. Ulnar neuropathy represented one-third of all nerve injuries and was the most frequent nerve injury. Less-frequent sites of nerve injury were the brachial plexus (23%) and the lumbosacral nerve roots (16%). In a large proportion of cases, the exact mechanism of injury was unclear despite evidence of intensive investigation in the claim files. Median payment for nerve damage claims involving disabling injury was

Awareness during anesthesia: a closed claims analysis.

56,000, which was significantly lower than the

Airway injury during anesthesia: a closed claims analysis.

225,000 median payment for claims for disabling injury not involving nerve damage (P less than 0.01). The closed claims reviewers judged that the standard of care had been met significantly more often in claims involving nerve damage than in claims not involving nerve damage. The authors conclude that nerve damage is a significant source of anesthesia-related claims but that the exact mechanism of nerve injury is often unclear. In particular, ulnar nerve injuries seemed to occur without identifiable mechanism.