Incidence and risk factors for delirium and other adverse outcomes in older adults after coronary artery bypass graft surgery

OBJECTIVE: To determine the incidence and risk factors for delirium after coronary artery bypass graft (CABG) surgery. DESIGN: Prospective cohort. SETTING: Cardiac surgery units of a tertiary care hospital. PARTICIPANTS: Consecutive patients over age 65 years undergoing elective CABG surgery. Exclusion criteria included preoperative sensory or language barriers. INTERVENTIONS: Each patient was assessed within 24 h before surgery for baseline demographic, medical and functional data. Incident delirium (within four postoperative days) was diagnosed by a study physician. Nine potential risk factors for delirium were subjected to univariate and multivariate analysis. MAIN RESULTS: Of 75 consenting patients, three died during or soon after surgery and one was still comatose at follow up. Of the remaining 71 participants, 23 (32%) experienced delirium. Those with delirium were more likely than those without delirium to have a history of a stroke (21% versus 4%, respectively, P = 0.032) and to have had a longer duration of cardiopulmonary bypass (CPB) (113 mins versus 95 mins, respectively, P = 0.025). A tendency to have experienced low cardiac output (83% versus 58%, respectively, P = 0.061) postoperatively was also noted. Multivariate analysis confirmed past stroke and duration of cardiopulmonary bypass as risk factors. CONCLUSIONS: Delirium in the elderly after CABG surgery is common. Its occurrence may be predisposed by a history of a stroke and precipitated by a longer duration of CPB.