Fig. 1. Comparisons of total time in the postanesthesia care unit (PACU) in different clinical categories. ( Upper left ) Comparison of Bispectral Index (BIS)–monitored patients and controls. ( Upper right ) Comparison by anesthetic groups: pent/iso = thiopental–isoflurane; pr/iso = propofol–isoflurane; pent/sevo = thiopental–sevoflurane; pr/sevo = propofol–sevoflurane. P < 0.0001 by analysis of variance for all groups. P values for intergroup comparisons: pr/sevo versus pent/sevo, P = 0.0169; pent/iso versus pr/iso, P = 0.0003; pr/sevo versus pr/iso, P < 0.0001; pent/iso versus pent/sevo, P < 0.0001; pr/sevo versus pent/iso, P < 0.0001; pr/iso versus pent/sevo, P = not significant. ( Lower left ) Comparison of groups categorized by duration of anesthesia: P < 0.0001 by analysis of variance. For all groups, P values for intergroup comparisons: 0–100 versus 101–200 min, P < 0.0001; 101–200 versus 201–400 min, P < 0.0001. ( Lower right ) Comparisons of surgical categories. ABD = abdominal surgery; FMJ = major body surface surgery; N/A = other surgical procedures; OMI = minor orthopedic surgery; PMJ = major orthopedic surgery, SMI = minor body surface surgery. P < 0.0001 by analysis of variance for all groups.