RÉSUMÉ
BACKGROUND: Delirium, defined as an acute disorder of attention and global cognitive function is a common, serious and potentially preventable source of morbidity and mortality in hospitalized elderly patients. Different studies have shown that existence of premorbid depressive illness and use of psychotropic drugs can contribute to delirium. OBJECTIVE: To assess the incidence of post operative delirium in elderly patients with pre morbid depressive illness and on psychotropic medications undergoing coronary artery bypass grafting (a major cardiac surgery). MATERIALS AND METHODS: Prospective cohort study, Study Period: 1 ½ years. Using a prepared questionnaire after obtaining fully informed written consent. 3 visits for each patient: 1) before surgery, 2) in the ICU: 48 hours after surgery, 3) In ward after shifting out from ICU. Details from patients, care givers and nursing staff regarding features of delirium are obtained. RESULTS: Out of total 250 patients included in the study, 43 (17.2%) patients developed post operative delirium. Only 6 (20.7%) patients out of 29 who had pre morbid depression, developed post operative delirium compared to 37 (16.7%) patients out of 224 with no pre operative depression (p value: 0.6). Out of 28 patients who were on psychotropic drugs 5 (17.9%) patients developed post operative delirium compared to 38 (17.1%) patients out of 222 who did not use psychotropic drugs (P value: 1). Patients with pre morbid mental illness or those on psychotropic drugs have no increased risk to develop post operative delirium compared to general patients.