Impact of intraoperative methadone use on postoperative opioid requirements after cardiac surgery

Disclaimer In an effort to expedite the publication of articles, AJHP is posting manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time. Purpose Inadequate pain control after cardiac surgery increases postoperative morbidity. Increasing evidence suggests that perioperative intravenous (IV) methadone results in improved analgesia. This study evaluated the effect of intraoperative IV methadone on postoperative opioid requirements and surgical recovery. Methods A retrospective review of patients undergoing coronary artery bypass graft (CABG), valvular surgery or both between April 2017 and August 2018 was conducted. Patients were separated into a usual care cohort of those who received short-acting opioids (ie, IV fentanyl, hydromorphone, or morphine) alone or a methadone cohort of those who received IV methadone plus short-acting opioids. Opioid requirements were assessed within the first 24 hours of surgery (postoperative day [POD] 0) and 25 to 48 hours after surgery (POD 1) as oral morphine milligram equivalents (MME). Postoperative pain scores, adjunctive analgesia, time to extubation, use of noninvasive respiratory support (continuous positive airway pressure [CPAP] or bilevel positive airway pressure [BiPAP]), and intensive care unit (ICU) and hospital length of stay (LOS) were also evaluated. Results A total of 117 patients were evaluated (methadone cohort, n = 52; usual care cohort, n = 65). Median cumulative intraoperative opioid consumption was less in the methadone cohort (150 MME vs 314.1 MME; P < 0.0001). The methadone cohort required 44% fewer MME than the usual care cohort on POD 0 (median MME, 15.8 vs 36; P = 0.025), with low and not significantly different opioid use in both cohorts on POD 1 (15.5 MME vs 7.5 MME; P = 0.47). Weight-based methadone dosing ranged from 0.1 to 0.4 mg/kg (mean, 0.22 mg/kg). There were no significant differences in pain scores, time to extubation, use of CPAP or BiPAP, or ICU and hospital LOS. Conclusion Intraoperative IV methadone in cardiac surgery patients was safe and significantly reduced intraoperative and postoperative opioid requirements on POD 0.