One-hundred consecutive patients undergoing aesthetic surgical procedures with adjunctive intravenous sedation in an office-based ambulatory surgical facility were monitored by an anesthesiologist with an ECG, stethoscope, automatic sphygmomanometer, and pulse oximeter. The pulse oximeter detected hypoxemia occurring intraoperatively and in the recovery room earlier than the traditional methods of monitoring. By detecting early drops in the SAO2 with the pulse oximeter, appropriate corrective measures could be instituted and titration of intravenous anesthetics adjusted, avoiding progression to more profound hypoxemia and thus resulting in the safer delivery of anesthesia. The pulse oximeter is a useful and recommended adjunct to the traditional methods of monitoring in an office-based ambulatory surgical facility.