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The purpose of this presentation is to report findings and discuss practice and research implications from two exploratory studies of delirium among patients who underwent “off-pump” coronary artery bypass graft surgery. The first study focused on the etiologic correlates, the second study focused on the patterns and course of delirium. Thirty-seven consenting patients (median age 68 years, 95% White, 81% male) with no history of cognitive impairment or substance abuse were screened every 12 hours, from 24 hours after surgery to a median of postoperative day 3. Five patients with a “positive” screen were assessed via the Confusion Assessment Method for the ICU and NEECHAM Confusion Scale until their delirium resolved. Pre- and post-operative Mini-Mental State Exam (MMSE) scores were obtained. The delirium group (n = 5, 13.5%) had more predisposing factors (older age, p = .01; a tendency toward poorer preoperative cardiac and renal functions, p < .1), overall delay in recovery (longer ICU stay, p = .02; a tendency toward longer hospital stay, p < .1), and a tendency to have more precipitating factors (postoperative hypoxia, renal failure, pneumonia, and unstable vital signs, or narcotics use) than the non-delirium group (n=32). The delirium course included an “emergence” (without a lucid period) and an “interval” (with a 1- to 3-day lucid period) patterns with “short-term” (1-2 days) period. A decline in the MMSE score was observed among “emergence” delirium patients. Correlates and antecedent events of delirium identified in the study were consistent with the literature. Frequent and systematic observation enables accurate identification of subtle delirium symptoms or delirium of a sudden onset. Interventions should be tailored to different patterns of delirium. A larger study that includes older patients with greater acuity and disease severity is recommended to evaluate whether the findings are robust.