Effect of patient-controlled sedation on recovery from ambulatory monitored anesthesia care

Patient-controlled sedation (PCS) with propofol has been shown to be an effective means of conscious sedation during monitored anesthesia care. The purpose of this study was to assess both the intraoperative conduct and postoperative recovery of patients receiving propofol for conscious sedation, randomized to either PCS or anesthetist-controlled sedation (ACS). Forty-three patients scheduled for outpatient procedures requiring monitored anesthesia care were randomized to PCS or ACS. Both groups received an initial bolus of propofol 0.5 mg/kg and fentanyl 1 microgram/kg i.v., followed by an identical background infusion of propofol 50 micrograms/kg per minute. Subsequent doses of propofol 30 mg i.v. were either self-administered (PCS) or administered at the discretion of the anesthetist (ACS). Variables measuring hemodynamics, ventilation, saturation, and level of sedation were measured at baseline, after initial bolus of propofol and fentanyl, after skin incision, at last stitch, at admission to recovery, and 1 hour later. More propofol was used by the PCS group (P < 0.05). Finger-tapping was slower and responsiveness scores were lower in the PCS group at the end of the procedure (P < 0.05). More patients in the PCS group required oxygen supplementation (saturation < 90%) on admission to recovery (P < 0.05). At 1 hour after recovery admission, however, there were no differences between groups. These results indicate that when patients determine their own sedation, they are more sedated at the end of a procedure than when the anesthetist determines the level of sedation.