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KEY POINTS
Anesthesia risk estimates are influenced by the circumstances in which they are generated; estimates derived from one site or population may not be valid in other settings or specific patients.
The risk of death related primarily to anesthesia is estimated to be as low as 1 in 200,000 anesthetics in some large populations, reflecting improvement of perhaps two orders of magnitude over more than 70 years.
Despite the very low anesthesia-attributable mortality rate, the large and increasing number of anesthetics engenders a substantial public health burden of mortality and morbidity, much of which may be preventable.
The overall low anesthesia-attributable mortality should not be a cause for complacency but rather an impetus for continued emphasis on improving anesthesia safety, particularly for high-risk patients and high-risk procedures.
Most anesthesia risk results from patient-specific characteristics, with additional contributions from surgical and anesthesia factors, but there is growing recognition that organizational culture and other characteristics of the clinical setting, including experience, teamwork, and communication, are important contributors to overall risk.
The American Society of Anesthesiologists physical status classification correlates with risk for mortality and morbidity, but it is somewhat subjective and, without additional clinical information, is alone not as strong a predictor of poor outcomes as other morbidity-specific indicators.
Although randomized clinical trials have rightly become the gold standard for establishing efficacy in clinical research, randomized clinical trials have a limited role in studying anesthesia risk, particularly because they cannot efficiently and at reasonable cost parse the confounding clinically relevant variables.
Well-conducted observational studies reveal that anesthesia risk is influenced more by how the anesthesia provider delivers care rather than which specific drugs and techniques are used. Thus, careful attention to factors such as blood pressure, perfusion, oxygenation, body temperature, and depth of anesthesia are often more beneficial than the specific anesthetic drug or technique that is selected.
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“How risky is anesthesia?” patients often wonder. Their concern really is multipart. First, how likely is something to go wrong; then, what “bad things” could happen; and, finally, what can be done to reduce the risk to me and to others in the future?
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This concern for enhanced anesthesia-related safety has special poignancy because anesthetic care usually confers no therapeutic benefit per se. Rather, it facilitates other therapeutic or diagnostic interventions. The potential for harm is expressed by a variety of risk metrics, most commonly as the incidence rate for an adverse event. Such metrics enable estimating the contributions of various aspects of anesthetic care (eg, anesthetic techniques and drugs, clinical care sites, temporal factors such as duration of hypotension or hypoxemia, promptness of interventions) to overall anesthetic risk allow clinicians to formulate care strategies that are evidence based and form the basis for comparative effectiveness studies that evaluate new drugs, anesthetic methods, and specific procedures. These diverse approaches have included inquests and closed malpractice-liability claims; case reports and series; study ...