Incidence and risk factors for unplanned intensive care unit transfer from the postanesthesia care unit: a...

To investigate the incidence and risk factors for unplanned intensive care unit (ICU) admission from the postanesthesia care unit (PACU) in adults following general anesthesia.

In this case-control study, we retrospectively collected data from 98,738 adult patients who underwent general anesthesia and entered into PACU between January 2021 and January 2024. Patients with unplanned ICU admission from the PACU (UIAP) were classified as the UIA group. Control group (who were routinely discharged from the PACU to the ward) were matched 1:3 with UIA group based on operative date (± 1 month), sex, and age (± 3 years). Clinical data were collected through medical record. Univariate and multivariate analysis were performed to identify risk factors for UIAP and to develop a predictive model.

During the study period, a total of 98,539 eligible patients were transferred to the PACU after surgery, of whom 113 (0.115%) required a UIAP. The occurrence of UIAP significantly increased the risk of ICU readmission [odds ratio (OR) = 21.0, 95% confidence interval (CI): 2.612-168.843, P < 0.001] and 30-day readmission (OR = 6.5, 95% CI: 2.530-16.700, P < 0.001) and did not significantly affect In-hospital mortality. Hypoxemia (34.51%) and delayed awakening (29.20%) were the most common reasons for UIAP. Multivariate analysis identified emergency surgery (OR = 17.494, 95% CI: 4.653-65.776, P < 0.001), ASA classification (OR = 5.662, 95% CI: 1.888-16.981, P = 0.002), ≥ 2 comorbidities (OR = 4.337, 95% CI: 1.867-10.078, P = 0.001), increased intraoperative blood loss (OR = 1.003, 95% CI: 1.000-1.005, P = 0.029) and longer operative time (OR = 1.007, 95% CI: 1.003-1.012, P = 0.001) as risk factors for UIAP. Moreover, increased preoperative hemoglobin level was identified as protective factor for UIAP (OR = 0.975, 95% CI: 0.957-0.993, P = 0.007). Analysis indicates that when preoperative hemoglobin level fall below 120 g/L, the risk of developing UIAP increases by 3.69 times (95% CI: 2.097-6.490, P < 0.001). The nomogram model in this study demonstrated strong discriminatory power (AUC = 0.888, 95% CI: 0.844-0.932) and good calibration upon internal validation.

In adult patients who underwent general anesthesia surgery, the incidence of UIAP was 0.115%. UIAP was significantly associated with an increased risk of ICU readmission. We identified emergency surgery, a higher ASA classification, ≥ 2 comorbidities, increased intraoperative blood loss and longer operative time as potential risk factors for unplanned transfer from the PACU to the ICU after general anesthesia. Additionally, increased preoperative hemoglobin level was a protective factor for UIAP patients.

Chinese Clinical Trial Registry (Registration No.ChiCTR2500104205), 12 June, 2025. Retrospectively registered.