THE INITIAL CLINICAL-EXPERIENCE OF 1819 PHYSICIANS IN MAINTAINING ANESTHESIA WITH PROPOFOL - CHARACTERISTICS ASSOCIATED WITH PROLONGED TIMETO AWAKENING

In October 1989, propofol underwent Phase IV Food and Drug Administrat ion testing that involved 25,981 patients, 1722 institutions, and 1819 anesthesiologists. Participants were 18-80 yr of age and ASA physical status I-III; they could not have a continuing pregnancy or prior adv erse anesthetic experience. Anesthesiologists completed detailed forms to describe their use of propofol in this three-step study: propofol for induction only (Step 1), for induction and then maintenance by int ermittent bolus injection (Step 2), or for continuous infusion (Step 3 ). In early 1992, our group of anesthesiologists and epidemiologists a nalyzed the resulting data base. We evaluated data from 14,882 patient s (8095 given bolus injections and 6787 given continuous infusion) to determine factors predicting prolonged time (>15 min after cessation o f all anesthesia) to awakening, one measure of recovery from anesthesi a. The incidence of prolonged awakening was 6.8% (1016 patients); the median and mean (+/- SD) times to awakening were, respectively, 5 min and 7.2 +/- 7.3 min. The following variables were associated (P < 0.05 ) with prolonged awakening from propofol maintenance anesthesia: a tot al dose of propofol >8 mg/kg, male gender, endotracheal intubation, ag e >65 yr, abdominal surgery, continuous infusion of propofol, and conc omitant use of isoflurane or benzodiazepines. These results support th e clinical impression that recovery from propofol anesthesia is remark ably rapid; although the vast majority of physicians participating in this study were using propofol for maintenance for the first time, onl y 6.8% of patients had awakening times exceeding 15 min.