Abdominal aortic aneurysm patients remain at risk for delirium on the surgical ward after intensive care unit dismissal

BACKGROUND: The incidence of delirium following open abdominal aortic aneurysm (AAA) surgery is significant, with incidence rates ranging from 12% to 33%. However, it remains unclear on what level of care a delirium develops in AAA patients. The aim of this study was to investigate the incidence of delirium in the ICU and on the surgical ward after AAA surgery. METHODS: A single-center retrospective cohort study was conducted that included all patients treated electively for an open AAA repair and patients who underwent emergency treatment for a ruptured AAA between 2013 and 2018. The diagnosis of delirium was verified by a psychiatrist or geriatrician using the Diagnostic and Statistical Manual of Mental Disorders (DSM-V) criteria. The incidence of delirium was calculated. Cox proportional hazards regression analyses were used to analyze 6- and 12-month survival. RESULTS : A total of 135 patients were included, 46 patients (34%) had a delirium during admission. Of these, 30 patients (65%) developed a delirium in the ICU and 16 patients (35%) on the surgical ward. There was no significant difference in six months and twelve months mortality between the ICU and ward delirium groups (HR=1.64, 95% CI: 0.33-8.13, and HR=1.12, 95% CI: 0.28-4.47, respectively). CONCLUSIONS: Delirium frequently occurs in patients who undergo AAA surgery. This study demonstrated that patients on the surgical ward remain at risk of developing a delirium after ICU dismissal. Patients with ICU delirium differ in clinical characteristics and outcomes from patients with a delirium on the surgical ward.