The WHO2SAFE Score: A Predictive Tool for Postoperative Oxygen Requirement After PACU Recovery

Background: This study aimed to develop a scoring system that predicts postoperative oxygen requirements, enhances clinical decision-making, reduces unnecessary oxygen use, and improves the efficiency of postoperative respiratory care. Methods: This retrospective study included patients who underwent elective non-cardiac surgery with general anesthesia between 1 January 2018 and 31 December 2022. The outcome of the study was the postoperative oxygen requirement at PACU discharge. Predictors with significance were used to create a scoring system. Results: Among the 42,378 cases, 14.9% required supplemental oxygen at PACU discharge. The WHO2SAFE score, which ranges from 0 to 15, incorporates eight independent risk factors, given in the mnemonic WHO₂SAFE: intraoperative wheezing, intraoperative hypotension, obesity, operative time ≥ 180 min, sleep apnea, ASA classification ≥ 3, female, and elderly. Conclusions: The WHO₂SAFE score provides a practical tool for predicting the need for supplemental oxygen at PACU discharge via the web, facilitating early intervention and efficient resource utilization. A cutoff score of 6 facilitates clinicians to identify high-risk patients who benefit from close observation while minimizing unnecessary oxygen use in low-risk individuals.