Supplemental oxygen after ambulatory surgical procedures.

The aim of this study was to determine the need for supplemental oxygen during recovery from general anesthesia for ambulatory surgery in healthy women without obesity or respiratory disease. Arterial oxygen saturation by pulse oximetry (SpO2) was monitored throughout the first postoperative hour in 164 patients. The patients breathed room air during recovery. Supplemental oxygen was given only to those who became hypoxemic (SpO2 less than or equal to 92%). It was discontinued at the end of 15 minutes and reinstituted for another 15 minutes if hypoxemia recurred. Twelve patients (7%) became hypoxemic and required supplemental oxygen for various periods of time up to 105 minutes. The need for supplemental oxygen increased with increasing age (P less than 0.05) but was not associated with a history of cigarette smoking, tracheal intubation, amount of opioids or sedatives given intraoperatively, anesthetic duration, or level of consciousness during recovery. Hypoxemia was neither predictable nor clinically apparent. We recommend that, unless arterial oxygenation is monitored, ambulatory patients should routinely receive supplemental oxygen during recovery from general anesthesia.