Risk factors of postoperative intensive care unit admission during the COVID-19 pandemic: A multicentre retrospective cohort study

Background: During the Coronavirus disease 2019 (COVID-19) pandemic, intensive care unit (ICU) capacity was scarce. Since surgical patients also require ICU admission, determining which factors lead to an increased risk of postoperative ICU admission is essential. This study aims to determine which factors led to an increased risk of unplanned postoperative ICU admission during the COVID-19 pandemic. Methods: This multicentre retrospective cohort study investigated all patients who underwent surgery between 9 March 2020 and 30 June 2020. The primary endpoint was the number of surgical patients requiring postoperative ICU admission. The secondary endpoint was to determine factors leading to an increased risk of unplanned postoperative ICU admission, calculated by multivariate analysis with odds ratios (OR's) and 95% confidence (CI) intervals. Results: One hundred eighty-five (4.6%) of the 4051 included patients required unplanned postoperative ICU admission. COVID-19 positive patients were at an increased risk of being admitted to the ICU compared to COVID-19 negative (OR 3.14; 95% CI 1.06-9.33; p = 0.040) and untested patients (OR 0.48; 95% CI 0.32-0.70; p = 0.001). Other predictors were male gender (OR 1.36; 95% CI 1.02-1.82; p = 0.046), body mass index (BMI) (OR 1.05; 95% CI 1.02-1.08; p = 0.001), surgical urgency and surgical discipline. Conclusion: A confirmed COVID-19 infection, male gender, elevated BMI, surgical urgency, and surgical discipline were independent factors for an increased risk of unplanned postoperative ICU admission. In the event of similar pandemics, postponing surgery in patients with an increased risk of postoperative ICU admission may be considered.