Incidence and risk factors for unplanned intensive care unit transfer from the postanesthesia care unit: a propensity score-matched analysis

Objective The aim of this study was to investigate the incidence and risk factors for unplanned transfer from the postanesthesia care unit (PACU) to the intensive care unit (ICU) in adult patients after general anesthesia. Methods This was a retrospective case‒control study that included adult patients with UIAP (unplanned ICU admission from the PACU) who underwent general anesthesia procedures between January 2021 and January 2024. The control group comprised patients transferred back to the ward from the PACU who were matched (1:1) for operation date, sex, age, BMI, surgical classification, and type of surgery to those in the case group. Results During the study period, a total of 97,704 patients were transferred to the PACU after surgery, and 113 unplanned ICU transfers occurred (0.116%). The most common reasons for unplanned transfers from the PACU to the ICU were hypoxemia (34.5%) and delayed awakening (29.2%). According to the multivariate analysis, emergency surgery [odds ratio (OR) = 3.366, 95% confidence interval (CI) = 1.186, 9.552], ASA classification (OR = 12.287, CI = 3.064, 49.280), coronary artery disease (OR = 5.129, CI = 1.526, 17.240), hemoglobin level (OR = 0.369, CI = 0.192, 0.711), blood loss volume (OR = 2.386, CI = 1.262, 4.510) and operation time (OR = 2.033, CI = 1.288, 3.210) were recognized as independent risk factors for UIAP after general anesthesia. Conclusion In adult patients who underwent general anesthesia procedures, the incidence of UIAP was 0.116%. We identified emergency surgery, coronary artery disease, ASA classification, preoperative hemoglobin level, blood loss volume and operation time as independent risk factors for unplanned transfer from the PACU to the ICU after general anesthesia. This would help clinicians to better predict the perioperative risk stratification of patients, thereby improving their prognosis. Trial registration Chinese Clinical Trial Registry (Registration No.ChiCTR2500104205), 12 June, 2025. Retrospectively registered.