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.