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 centre 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 analyse six and twelve months 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.