General anesthesia does not impair simulator driving skills in volunteers in the immediate recovery period - A pilot study

Purpose: The current recommendations to refrain from driving for 24 hr after general anesthesia (GA) lack evidence. Our objective was to measure impairment of driving performance at various time intervals after anesthesia using driving impairment at different blood alcohol concentrations (BAC) as a gold standard for comparison. Methods: Institutional Review Board approval was obtained. A cross-over design, within subject comparison was used. Twelve volunteers were randomized to three treatments: GA, alcohol, and no drug. Psychomotor recovery was assessed by Digit Symbol Substitution Test (DSST) and Trieger Dot Test (TDT). On the anesthetic day, GA was induced with propofol 2.5 mg·kg^-1 and fentanyl 1μg·kg^-1 and maintained with N₂O-O₂ 50:50 and approximately one minimum alveolar concentration of desflurane by spontaneous ventilation for 30 min. Driving simulator test runs occurred at two, three, four, and 24 hr postanesthesia. On the alcohol treatment day, a vodka and orange juice beverage was administered to reach the legal limit for BAC in the province of Ontario, Canada (BAC 0.08%). On the control day, no drug was given. Driving simulator test runs corresponded to the same time of day as the postanesthetic test runs. Two-way analysis of variance for dependent samples (ANOVA) was performed using the SAS program. P values of less than 0.05 were considered significant. Results: There was no significant difference in postanesthetic driving skills at two, three, and four hours postanesthesia, and the corresponding control sessions. There was no significant difference among the three sessions with respect to pen and paper tests of psychomotor performance. Performance during the alcohol session differed significantly from that during the control and postanesthetic sessions. Conclusion: Certain driving skills return by two hours after one half hour of GA of propofol, desflurane, and fentanyl in a group of young volunteers.