Predictors of Postoperative Morphine Milligram Equivalents in Cardiac Surgery

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ObjectivesGiven both the short- and long-term deleterious effects of opioids, there has been increased focused on reducing the use of postoperative opioid analgesia. As patients undergoing cardiac surgery often require high levels opioids postoperatively, understanding risk factors for increased postoperative opioid use may be helpful for the development of patient specific opioid sparing pain regimens for this patient population. DesignThis study was a retrospective analysis of data from our electronic medical records and the Society of Thoracic Surgeon's database. SettingThis was a single-institution study at an academic medical center. ParticipantsAll patients undergoing open adult cardiac surgery were included. Exclusion criteria were patients with continuous IV narcotic drips and operative mortality. InterventionsAs this was a retrospective study, no interventions were conducted on the participants. Measurements and Main ResultsData for patient's postoperative opioid requirements was extracted from the electronic medical record. Total opioid use on postoperative days 0-3 was converted to morphine milligram equivalent (MME) via standard conversion factors. A total of 1,604 patients were included in the study. 456 patients were female, and 1,066 underwent coronary artery bypass grafting. Patients undergoing CABG had 31.0% increased use of MME (P<.001), patients with liver disease had 76.3% increased use of MME (P=.005), and patients with patient-controlled analgesia had 48.8% increased use of MME (P<.001) during postoperative days 0-3. Younger age (P<.001) and increased BMI (P<.001) were also associated with increased MME prescription. ConclusionsPatients undergoing CABG, patients with liver disease, patients with patient-controlled analgesia, in addition to younger age and increased BMI, are associated with increased narcotic use after cardiac surgery. Implementation of more aggressive perioperative multimodal opioid sparing regimens should be considered for these patient groups.