Hazards in anaesthetic practice: general considerations, injury, and drugs.

The hazards of anaesthesia should be considered in the context of the hazard of surgery and of the pathology for which the surgery is being undertaken. Anaesthesia has become progressively safer since the successful demonstration of ether anaesthesia in Boston, Massachusetts, United States in 1846 and the first reported death under anaesthesia in 1847. The best estimation of the rate of anaesthesia-related mortality comes from the anaesthesia mortality review committees in Australia and New Zealand, where data have been collected under essentially consistent definitions since 1960, and reports are amalgamated under the auspices of the Australian and New Zealand College of Surgeons. An internationally accepted definition of anaesthetic mortality is overdue. Extending the time for inclusion of deaths from 24 h to 30 days or longer substantially increases estimated rates of mortality. Attribution of cause of death may be problematic. Even quite small degrees of myocardial injury in patients undergoing non-cardiac surgery increase the risk of subsequent mortality, and in older patients, 30-day all-cause mortality following inpatient surgery may be surprisingly high. Patients should be given a single estimate of the combined risk of surgery and anaesthesia, rather than placing undue emphasis on the risk from anaesthesia alone. Hazards may arise from equipment or from drugs either directly or through error. Error often underlies harmful events in anaesthesia and may be made more likely by fatigue or circadian factors, but violations are also important. Training in expert skills and knowledge, and in human factors, teamwork, and communication is key to improving safety.