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 h 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 1437 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.