Association of Pain with Atrial Fibrillation and Delirium after Cardiac Surgery; A DECADE Sub-Study

Abstract Objective: We aim to evaluate the effects of postoperative pain on the incidence of atrial fibrillation and delirium in patients having surgery with cardiopulmonary bypass. Design: Post-hoc analysis of the DECADE a randomized, placebo-controlled trial. Setting: Tertiary, academic hospital. Participants: 605 adults from the DECADE enrolled at Cleveland Clinic Main Campus, who had had surgery with cardiopulmonary bypass. Interventions: Dexmedetomidine versus placebo started before surgical incision, and postoperatively was maintained until 24 h. Measurements Primary outcomes were Atrial fibrillation, diagnosed by clinicians in ICU, presence of delirium assessed with the Confusion Assessment Method for the ICU, data on pain scores and opioid consumption, occurring between ICU admission and the earlier of postoperative day 5 or hospital discharge. Results: Postoperative pain level was similar among patients with or without atrial fibrillation. Two hundred six (34%) patients had atrial fibrillation and ninety-two (15%) had delirium before hospital discharge within the first 5 postoperative days. The risk of atrial fibrillation was not significantly different between groups (hazard ratio: 1.09; 97.5% CI: 0.99, 1.20, P = 0.039), there was no associations between postoperative pain and the risk of postoperative delirium (hazard ratio: 0.96; 97.5% CI: 0.84, 1.11; P = 0.57). Postoperative opioid consumption was neither significantly associated with postoperative atrial fibrillation nor delirium. Conclusions: Atrial fibrillation and delirium are not associated with pain after cardiac surgery. Opioid use was not associated with atrial fibrillation and delirium. Since both atrial fibrillation and delirium have multifactorial nature, further studies should be focused on other plausible mechanisms.