BACKGROUND: Patients are most likely to develop severe arterial desaturation during the early postoperative period. Respiratory complications in postanesthesia care unit (PACU) increase the risk of major adverse cardiac outcomes, unanticipated ICU admission or delay in PACU discharges. The increased use of inhalation agents with low blood : gas partition coefficient, intermediate-acting muscle relaxants and continuous pulse oximeter monitoring over the past 10 years may have altered the incidence of immediate postoperative hypoxemia. This study was undertaken to determine the overall incidence of immediate postoperative hypoxemia in PACU.

METHODS: Hypoxemia was definsed as a pulse oxygen saturation (SpO₂) of less than 90% lasting for at least 20 sec. The occurrence of hypoxemia was documented and notified to the anesthesiologist by PACU nurses. The anesthesiologist recorded contributory factors and the management modalities used in patients with hypoxemia.

RESULTS: The incidence of hypoxia was 3.5 per 1,000 patients after general anesthesia. Most hypoxemic events (88%) occurred during the first 5 minutes after arrival in PACU. Upper airway obstruction was the major contributory factor for hypoxemia (75.5%) and most of these patients recovered simply after a jaw thrust or the insertion of an oral or nasal airway.

CONCLUSIONS: Postoperative hypoxemia does not occur often in PACU, but when it does, it is associated with major morbidity and increased medical costs. Therefore, oxygen supply is recommended in patients with risk factors of hypoxemia during transfer from operating rooms to PACU. Close monitoring of hypoxemia in PACU is needed in all patients after general anesthesia.