Anesthesia risk estimates are influenced by the circumstances in which they are generated; estimates developed in one clinical setting or selected population may not be relevant to other settings or specific patients.
The risk of death related primarily to anesthesia is estimated to be as low as approximately 1 in 200,000 anesthetics in some large populations and reflects improvement of perhaps 2 orders of magnitude over more than 60 years.
Despite the very low anesthesia-attributable mortality rate, the very large and increasing number of anesthetics engenders a substantial burden of mortality and morbidity, much of which may be preventable.
The very low anesthesia-attributable overall mortality should not be a cause for complacency but rather an impetus toward a greater emphasis on improving anesthesia-related morbidity in selected subpopulations of high-risk patients or high-risk procedures.
Approximately 75% of risk actually relates directly to patient-specific characteristics, including age, gender, and comorbidity; 20% to surgical issues, such as experience and judgment; and the remaining 5% to anesthesia factors, including experience, board certification, pharmacologic issues, and overall management of care.
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 measures.
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 identify the confounding clinically relevant variables.
Well-conducted observational studies reveal that anesthesia risk is influenced much more by how the anesthesiologist provides care rather than specifically what methods are used. Thus careful attention to such factors as blood pressure, perfusion, oxygenation, body temperature, and depth of anesthesia, for example, are often more beneficial than the specific anesthetic drug or technique that is selected.
"What is the risk of 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 following me in the future?
Anesthesia care providers try to allay patients' concerns by citing statistics based on large populations or reassuring that common anesthesia side effects, however annoying, are fortunately transient. Serious, life-threatening complications now are uncommon, if not rare. Such comments may offer comfort, but they do little to specify the magnitude and types of risks that a given individual faces, nor do they indicate that we know how to reduce the risks. The current national focus on patient safety leads to expectations that we provide more to our patients, and this chapter will provide such information.
The concern for enhanced safety has special import for anesthesia care because anesthesia care usually confers no therapeutic benefit but rather facilitates other therapeutic or diagnostic interventions. The potential for harm is expressed ...