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 c oronary 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 CA BG surgery. Exclusion criteria included preoperative sensory or language ba rriers. INTERVENTIONS: Each patient was assessed within 24 h before surgery for bas eline demographic, medical and functional data. Incident delirium (within f our postoperative days) was diagnosed by a study physician. Nine potential risk factors for delirium were subjected to univariate and multivariate ana lysis. MAIN RESULTS: Of 75 consenting patients, three died during or soon after su rgery and one was still comatose at follow-up. Of the remaining 71 particip ants, 23 (32%) experienced delirium. Those with delirium were more likely t han those without delirium to have a history of a stroke (21% versus 4%, re spectively, P=0.032) and to have had a longer duration of cardiopulmonary b ypass (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 stro ke and duration of cardiopulmonary bypass as risk factors. CONCLUSIONS: Delirium in the elderly after CABG surgery is common. Its occu rrence may be predisposed by a history of a stroke and precipitated by a lo nger duration of CPB.