539: Impact of Perioperative Intravenous Acetaminophen on Opioid Consumption Post-Cardiothoracic Surgery

Introduction: Intravenous acetaminophen (IV APAP) has been shown to reduce post-operative opioid consumption in some surgical subsets; however, there is limited data to support its use in the cardiothoracic surgery (CTS) population where the benefit of IV administration may be most pronounced secondary to reduced absorption of oral medications after cardiopulmonary bypass (CPB). Methods: This was a propensity-matched, pre- and post-analysis in patients undergoing CTS-CPB before and after implementation of one dose of IV APAP perioperatively as part of an Enhanced Recovery After Surgery (ERAS) protocol focused on multimodal pain management. The primary outcome was opioid consumption in the first 24 hours IV morphine milligram equivalents (MMEs). Secondary outcomes included several opioid-related adverse effects. Results: After propensity matching, 80 patients were included in each group. Significantly more patients in the IV APAP group received gabapentin (86.2% vs. 23.8%) and methocarbamol (40% vs. 21.2%) postoperatively; the median dose of oral acetaminophen in the first 24 hours was significantly higher in the IV APAP group (3004 mg vs. 2472 mg). Total IV MMEs in the first 24 hours postoperatively were 20.8 in the IV APAP group compared with 31.4 in the no IV APAP group (p=0.008). This difference was also seen in the first 6 hours (3.8 versus 6.6, p=0.001). Time to diet ordered was significantly shorter in the IV APAP group (11.9 versus 18.6 hours, p=0.001). Conclusions: Patients who received perioperative IV acetaminophen had significantly lower opioid consumption in the first 24 hours after CTS-CPB compared to patients who did not.