Delirium associated with buprenorphine use in cardiac surgery: A retrospective cohort study

BACKGROUND AND AIMS: Delirium is defined as an acute disturbance in consciousness along with impaired thought processing and easy distraction. Buprenorphine is a mixed agonist–antagonist opioid analgesic. Few case reports have been published about the possible association between buprenorphine and delirium. The aim of this study was to look for an association between buprenorphine and postoperative delirium in patients undergoing off-pump coronary artery bypass grafting (CABG) surgery. METHODS: Retrospective data from 100 cases of off-pump CABG were collected. The patients were divided into two groups (50 patients each). In group I, buprenorphine was used for postoperative analgesia. In group II, buprenorphine was not used for postoperative analgesia. RESULTS: On post-operative day 0, there was no incidence of delirium in both groups. On post-operative days two and three, there was no incidence of delirium in group II, but a statistically significant incidence of delirium was seen in group I (P = 0.012, relative risk >1). The overall (all four days) incidence of delirium was higher in group I which was statistically significant (P = 0.006). The total number of delirium cases was seven (14%) in group I and out of the seven delirium cases, five patients (10%) had hyperactive delirium, and two patients (4%) had hypoactive delirium. CONCLUSION: Use of buprenorphine was associated with post-operative delirium, particularly of the hyperactive motoric subtype in off-pump CABG patients.