Frequency and risk factors for failed weaning from supplemental oxygen therapy after general anesthesia at a postanesthesia care unit: a retrospective cohort study

BACKGROUND: Patients are administered supplemental oxygen upon emergence from general anesthesia against the risk of hypoxia. However, few studies have assessed the weaning from supplemental oxygen therapy. This study investigated the frequency and risk factors of failure to discontinue supplemental oxygen at a postanesthesia care unit (PACU). METHODS: This retrospective cohort study was conducted in a tertiary hospital. We reviewed the medical records of adult patients admitted to the PACU after general anesthesia for elective surgery between January 2022 and November 2022. The primary endpoint was the frequency of failed weaning from supplemental oxygen therapy at PACU. A failed weaning was defined as oxygen saturation (SpO(2)) < 92% after discontinuing oxygen administration. The rate of failed discontinuation of supplemental oxygen at the PACU was assessed. Demographics, intraoperative, and postoperative factors were explored to determine potential associations with failed weaning from supplemental oxygen therapy using logistic regression analysis. RESULTS: We analyzed 12,109 patients. We identified 842 cases of failed weaning from supplemental oxygen therapy, with a frequency of 1:14 (95% confidence interval [CI], 1:15–1:13). Risk factors that showed the strongest associations with failed weaning included postoperative hypothermia (odds ratio [OR], 5.42; 95% CI, 4.40–6.68; P < 0.001), major abdominal surgery (OR, 4.04; 95% CI, 3.29–4.99; P < 0.001), and preoperative SpO(2) < 92% in room air (OR, 3.15; 95% CI, 2.09–4.64; P < 0.001). CONCLUSION: In the analysis of more than 12,000 general anesthetics, an overall risk of failed weaning from supplemental oxygen therapy of 1:14 was observed. The identified risk factors may help determine the discontinuation of supplemental oxygen administration at PACU. TRIAL REGISTRATION: Not applicable.