Association Between the Confusion Assessment Method for the Intensive Care Unit (CAM- ICU) and Prolonged Mechanical Ventilation Following Major Cardiac Surgery

Background Delirium is common after cardiac surgery and has been associated with adverse outcomes in critically ill patients. The Confusion Assessment Method for the Intensive Care Unit (CAM-ICU) is a validated tool for detecting delirium; however, few studies have explored its association with prolonged mechanical ventilation (PMV) following major cardiac surgery. This study aimed to investigate whether a positive CAM-ICU assessment is associated with PMV and other postoperative outcomes in this population. Methods We conducted a retrospective cohort study of 1,437 adult patients who underwent cardiac surgery in 2022. Delirium was assessed daily using the CAM-ICU during the early postoperative period. PMV was defined as ventilation lasting more than 24 hours after surgery. Clinical outcomes were analyzed using logistic regression and time-dependent Cox regression, with adjustments made using inverse probability of treatment weighting (IPTW). Results Among 1,437 patients, 281 (19.6%) were assessed as CAM-ICU positive in the early postoperative period. After IPTW adjustment, a positive CAM-ICU assessment was significantly associated with increased risk of PMV (odds ratio [OR] 3.60; 95% CI, 2.53–5.10; p < 0.001), reintubation (OR 3.37; 95% CI, 1.52–7.31; p = 0.002), intensive care unit (ICU) readmission (OR 2.53; 95% CI, 1.22–5.03; p = 0.010), and prolonged ICU stay after extubation (OR 2.95; 95% CI, 2.19–3.96; p < 0.001). Neither early death nor all-cause mortality differed significantly between groups after IPTW adjustment. Age-related analyses indicated that predicted ventilator duration was generally longer with a positive CAM-ICU assessment across most age groups, with attenuation of this difference in the very elderly (≥ 80 years). Conclusion An early postoperative positive CAM-ICU assessment was associated with higher risks of PMV, reintubation, ICU readmission, and prolonged ICU stay after major cardiac surgery. Routine CAM-ICU screening may help identify patients at risk of prolonged ventilation and enable timely, targeted interventions to improve postoperative respiratory recovery.