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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.

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BACKGROUND: Airway injury during general anesthesia is a significant source of morbidity for patients and a source of liability for anesthesiologists. To identify recurrent patterns of injury, the authors analyzed claims for airway injury in the American Society of Anesthesiologists (ASA) Closed Claims Project database. METHODS: The ASA Closed Claims database is a standardized collection of case summaries derived from professional liability insurance companies closed claims files. All claims for airway injury were reviewed in depth and were compared to other claims during general anesthesia. RESULTS: Approximately 6% (266) of 4,460 claims in the database were for airway injury. The most frequent sites of injury were the larynx (33%), pharynx (19%), and esophagus (18%). Injuries to the esophagus and trachea were more frequently associated with difficult intubation. Injuries to temporomandibular joint and the larynx were more frequently associated with nondifficult intubation. Injuries to the esophagus were more severe and resulted in a higher payment to the plaintiff than claims for other sites of airway injury. Difficult intubation (odds ratio = 4.53, 95% confidence interval [CI] = 2.36, 8.71), age older than 60 yr (odds ratio = 2.97, 95% CI = 1.51, 5.87), and female gender (odds ratio = 2.43, 95% CI = 1.09, 5.42) were associated with claims for pharyngoesophageal perforation. Early signs of perforation, e.g., pneumothorax and subcutaneous emphysema, were present in only 51% of perforation claims, whereas late sequelae, e.g., retropharyngeal abscess and mediastinitis, occurred in 65%. CONCLUSION: Patients in whom tracheal intubation has been difficult should be observed for and told to watch for the development of symptoms and signs of retropharyngeal abscess, mediastinitis, or both.

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BACKGROUND: Awareness during general anesthesia is a frightening experience, which may result in serious emotional injury and post-traumatic stress disorder. We performed an in-depth analysis of cases from the database of the American Society of Anesthesiologists Closed Claims Project to explore the contribution of intraoperative awareness to professional liability in anesthesia. METHODS: The database of the Closed Claims Project is composed of closed US malpractice claims that have been collected in a standardized manner. All claims for intraoperative awareness were reviewed by the reviewers to identify patterns of causation and standard of care. Logistic regression analysis was used to identify independent patient and anesthetic factors associated with claims for recall during general anesthesia compared to other general anesthesia malpractice claims. RESULTS: Awareness claims accounted for 79 (1.9%) of 4,183 claims in the database, including 18 claims for awake paralysis, i.e., the inadvertent paralysis of an awake patient, and 61 claims for recall during general anesthesia, ie., recall of events while receiving general anesthesia. The majority of awareness claims involved women (77%), younger than 60 yr of age (89%), American Society of Anesthesiologists physical class I-II (68%), who underwent elective surgery (87%). Most (94%) claims for awake paralysis represented substandard care involving errors in labeling and administration, whereas care was substandard in only 43% of the claims for recall during general anesthesia (P < 0.001). Claims for recall during general anesthesia were more likely to involve women (odds ratio [OR] = 3.08, 95% confidence interval [CI] = 1.58, 6.06) and anesthetic techniques using intraoperative opioids (OR = 2.12, 95% CI = 1.20, 3.74), intraoperative muscle relaxants (OR = 2.28, 95% CI = 1.22, 4.25), and no volatile anesthetic (OR = 3.20, 95% CI = 1.88, 5.46). CONCLUSIONS: Deficiencies in labeling and vigilance were common causes for awake paralysis. Claims for recall during general anesthesia were more likely in women and with nitrous-narcotic-relaxant techniques.

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BACKGROUND: Nerve injury associated with anesthesia is a significant source of morbidity for patients and liability for anesthesiologists. To identify recurrent and emerging patterns of injury we analyzed the current American Society of Anesthesiologists (ASA) Closed Claims Project Database and performed an in-depth analysis of claims for nerve injury that were entered into the database since the authors' initial report of the subject. METHODS: The ASA Closed Claims Database is a standardized collection of case summaries derived from the closed claims files of professional liability insurance companies. Claims for nerve injury that were not included in the authors' 1990 report were reviewed in-depth. RESULTS: Six hundred seventy (16% of 4,183) claims were for anesthesia-related nerve injury. The most frequent sites of injury were the ulnar nerve (28%), brachial plexus (20%), lumbosacral nerve root (16%), and spinal cord (13%). Ulnar nerve (85%) injuries were more likely to have occurred in association with general anesthesia, whereas spinal cord (58%) and lumbosacral nerve root (92%) injuries were more likely to occur with regional techniques. Ulnar nerve injury occurred predominately in men (75%) and was also more apt to have a delayed onset of symptoms (62%) than other nerve injuries. Spinal cord injuries were the leading cause of claims for nerve injury that occurred in the 1990s. CONCLUSION: New strategies for prevention of nerve damage cannot be recommended at this time because the mechanism for most injuries, particularly those of the ulnar nerve, is not apparent.

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BACKGROUND: Anesthesia gas delivery equipment is a potentially important source of patient injury. To better define the contribution of gas delivery equipment to professional liability in anesthesia, the authors conducted an in-depth analysis of cases from the database of the American Society of Anesthesiologists Closed Claims Project. METHODS: The database of the Closed Claims Project is composed of closed US malpractice claims that have been collected in a standardized manner. All claims resulting from the use of gas delivery equipment were reviewed for recurrent patterns of injury. RESULTS: Gas delivery equipment was associated with 72 (2%) of 3,791 claims in the database. Death and permanent brain damage accounted for almost all adverse outcomes (n = 55, 76%). Equipment misuse was defined as fault or human error associated with the preparation, maintenance, or deployment of a medical device. Equipment failure was defined as unexpected malfunction of a medical device, despite routine maintenance and previous uneventful use. Misuse of equipment (n = 54, 75%) was three times more common than equipment failure (n = 17, 24%). Misconnects and disconnects of the breathing circuit made the largest contribution to injury (n = 25, 35%). Reviewers judged that 38 of 72 claims (53%) could have been prevented by pulse oximetry, capnography, or a combination of these two monitors. Overall, 56 of 72 gas delivery claims (78%) were deemed preventable with the use or better use of monitors. The year of occurrence for claims involving gas delivery equipment ranged from 1962 to 1991 and did not differ significantly from claims involving other adverse respiratory events. CONCLUSIONS: Claims associated with gas delivery equipment are infrequent but severe and continue to occur in the 1990s. Educational and preventive strategies that focus on equipment misuse and breathing circuit configuration may have the greatest potential for enhancing the safety of anesthesia gas delivery equipment.

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BACKGROUND: Expert opinion in medical malpractice is a form of implicit assessment, based on unstated individual opinion. This contrasts with explicit assessment processes, which are characterized by criteria specified and stated before the assessment. Although sources of bias that might hinder the objectivity of expert witnesses have been identified, the effect of the implicit nature of expert review has not been firmly established. METHODS: Pairs of anesthesiologist-reviewers independently assessed the appropriateness of care in anesthesia malpractice claims. With potential sources of bias eliminated or held constant, the level of agreement was measured. RESULTS: Thirty anesthesiologists reviewed 103 claims. Reviewers agreed on 62% of claims and disagreed on 38%. They agreed that care was appropriate in 27% and less than appropriate in 32%. Chance-corrected levels of agreement were in the poor-good range (kappa = 0.37; 95% CI = 0.23 to 0.51). CONCLUSIONS: Divergent opinion stemming from the implicit nature of expert review may be common among objective medical experts reviewing malpractice claims.

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BACKGROUND: Prevention of hypothermia is an important aspect of anesthetic management. Methods used for its prevention may, however, cause cutaneous burns. We reviewed the American Society of Anesthesiologists (ASA) Closed Claims Project database to determine if there were recurrent patterns of injury arising from intraoperative warming methods. METHODS: The ASA Closed Claims Project database is a collection of closed malpractice claims that have been reviewed in a standardized format. All claims for burns were reviewed. RESULTS: Among the 3,000 total claims there were 54 burns, of which 28 resulted from materials or devices used to warm patients. Intravenous fluid bags or bottles warmed in an oven and then applied to the patient's skin were responsible for 18 of the 28 (64%) burns associated with warming devices. These burns from intravenous fluid bags or bottles occurred in predominantly healthy (ASA physical status 1-2) young (age 38 +/- 17 yr, mean +/- standard deviation) women undergoing routine gynecologic or peripheral orthopedic surgery under general anesthesia. Of the eight burns from electrically powered warming equipment, five resulted from circulating-water mattresses. CONCLUSIONS: Intravenous fluid bags or bottles warmed in an operating room oven represent a hazard to anesthetized patients. Because intravenous fluid bags or bottles are not an efficient method of patient warming, there seems to be little justification for their use.

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We developed a continuous quality improvement (CQI) program for anesthesia services based on self-reporting of critical incidents and negative outcomes through a dichotomous (yes/no) response on the anesthesia record. Immediate case investigation provides data for systematic peer review of anesthesia management. Trend analysis of the database of critical incidents and negative outcomes identifies opportunities for improvement. The CQI program resulted in the reporting of nearly twice as many problems related to anesthesia management (5% of all anesthetics) as did the checklist it replaced (2.7%). Escalation of patient care (3.2%) and operational inefficiencies (2.2%) were more common than patient injury (1.5% of all anesthetics). Among the 537 cases with anesthesia management problems were 119 human errors and equipment problems (22%). Regional nerve blocks and airway management represented the most common problem areas. Improvement in anesthesia services was made through prompt implementation of strategies for problem prevention devised by the practitioners themselves through peer review, literature review, and clinical investigations.

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A probability-summation model is introduced to provide quantitative criteria for discriminating independent from interactive effects of multiple laser exposures on biological tissue. Data that differ statistically from predictions of the probability-summation model indicate the action of sensitizing (synergistic/positive) or desensitizing (hardening/negative) biophysical interactions. Interactions are indicated when response probabilities vary with changes in the spatial or temporal separation of exposures. In the absence of interactions, probability-summation parsimoniously accounts for "cumulative" effects. Data analyzed using the probability-summation model show instances of both sensitization and desensitization of retinal tissue by laser exposures. Other results are shown to be consistent with probability-summation. The relevance of the probability-summation model to previous laser-bioeffects studies, models, and safety standards is discussed and an appeal is made for improved empirical estimates of response probabilities for single exposures.

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OBJECTIVE: The objective of this study was to prospectively examine the incidence of patient-related failure of pulse oximetry in the postanesthesia care unit (PACU). METHODS: We studied 2,937 patients who, after receiving anesthesia, were admitted to the PACU at the University of Washington Medical Center from December 1989 through May 1990. Pulse oximetry readings were recorded using a Nellcor N-200 oximeter without electrocardiographic synchronization. Failure was defined as the inability to obtain a pulse oximetry reading for 2 or more 15-minute periods after eliminating probe position or mechanical malfunctions. RESULTS: The overall failure rate in our study was 0.64%, with 19 patient-related pulse oximetry failures from 2,937 cases. Patients on whom the device failed were significantly older (62 +/- 18 vs 46 +/- 19 yr [mean +/- SD]; p < 0.01), had higher median American Society of Anesthesiologists status (3 vs 2), and had longer operations than nonfailure patients (328 +/- 182 vs 185 +/- 127 min; p < 0.01). There was no difference in the duration of PACU times for both groups. CONCLUSIONS: The failure rate and patient characteristics compare favorably with a previously published study of intraoperative pulse oximetry failure. We conclude that while the pulse oximeter is a reliable instrument for the measurement of blood oxygenation, there is a small but consistent incidence of patient-related failure with this monitoring device in the PACU.

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