Perioperative desaturation and risk factors in general anesthesia.

OBJECTIVE Despite advances in anesthetic technique, the incidence of perioperative desaturation in general anesthesia has remained high. Knowledge on factors associated with intraoperative desaturation is relatively scanty. The purpose of the present study was to investigate the distribution of time dependent intraoperative desaturation and factors predicting perioperative desaturation. MATERIAL AND METHOD A prospective observational analytic study was conducted. One thousand and ninety three patients schedule for elective surgery under general anesthesia (GA) were enrolled. Exclusion criteria were patients with preoperative arterial oxygen saturation (SpO2) < or = 95%, pregnant women, obvious difficult airway and those requiring mechanical ventilation postoperatively. Desaturation was defined as oxygen saturation < or = 95% for > or = 10 seconds. RESULTS Among 1093 eligible cases, 30 cases (2.74%) developed intraoperative desaturation. The probability of desaturation during induction, maintenance, and emergence were 0.55% (6/1093), 2.01% (22/1093), and 0.18% (2/1093), respectively. Occurrences of desaturation at the recovery room (RR) were noted in 224 patients (20.49%). Younger, obese patients, snorers, and lower respiratory tract infection were significant high-risk groups of intraoperative desaturation. Elderly, obese patients, snorers, positive history of pulmonary disease, modified Aldrete's score < or = 8, and duration of GA > or = 180 minutes predicted desaturation at RR. CONCLUSION Obesity and snorers were the high-risk groups of perioperative desaturation. Elderly patients are at lower risk of desaturation than children intraoperatively, but at a higher risk in the postoperative period Higher FiO2 should be given to high-risk patients during the intraoperative period. Desaturation can still occur at RR, even in patients who received oxygen. Pulse oximeter monitoring should be continued throughout RR care.