Physical status score and trends in anesthetic complications

Since deaths due to anesthesia have now become rare, emphasis in quality assurance of anesthetic care must focus on morbidity rather than only on mortality. To facilitate comparisons of outcomes, data from a large anesthesia follow-up program (N = 112,000 anesthetics) were used to evaluate the usefulness of the American Society of Anesthesiologists' Physical Status score (PS) as an independent predictor of nonfatal adverse anesthetic complications. For each patient, the anesthesiologist filled out a form containing information about the patient, the anesthetic, the operative procedure, and outcomes in the operating and recovery rooms. Postoperative complications were assessed by a designated anesthesia follow-up nurse. We calculated the PS-specific complication rate by dividing the number of complications to patients in each PS category by the number of anesthetics given to patients in the same category. We found that PS-specific complication rates increased with increasing PS scores for most complications sought. For intraoperative and recovery room complications, the PS-specific rates increased from 1978-80 and 1981-83 as compared to 1975-77. However, there was no increase over time in the rate of postoperative major complications. After adjusting for patient, anesthesia, and surgery-related variables by multiple logistic regression, the relative odds of having an intraoperative or postoperative major complication were increased for patients classified PS2, PS3 and PS4 & 5 as compared to PS1. However, those in higher PS categories were less likely to have a recovery room complication than PS1 patients.(ABSTRACT TRUNCATED AT 250 WORDS)