Routine Use of Intravenous Acetaminophen Safely Enhances Pain Control After Minimally Invasive Hepatectomies: a retrospective cohort study

Background Effective postoperative pain management is crucial after minimally invasive hepatectomy (MIH) to promote recovery, and multimodal analgesia strategies are used to reduce opioid requirements and improve outcomes. Multimodal therapies for postoperative pain management commonly comprise acetaminophen. However, the safety and efficacy of acetaminophen for postoperative analgesia in minimally invasive hepatectomy remains unestablished due to its hepatic metabolism. This study aimed to evaluate the safety and analgesic efficacy of routine intravenous acetaminophen administration following MIH. Methods The data of consecutive 50 participants who had undergone MIH were retrospectively analyzed. Regarding postoperative analgesia, participants were assigned to either the opioid-alone cohort (Cohort O) or opioid with routine intravenous acetaminophen cohort (Cohort A). Analgesic efficacy was evaluated using the numerical rating scale (NRS) over the first 2 postoperative days. The sum of opioid rescue doses and frequency of postoperative nausea and vomiting (PONV) were assessed. Analgesic safety was determined by monitoring prolonged elevated transaminase levels. Results Postoperatively, no statistically significant differences in the hepatic and renal functions and systemic inflammatory markers were observed between the two cohorts. On both postoperative day 1 and day 2, Cohort A showed lower NRS scores compared with Cohort O. Notably, almost all patients in Cohort A did not require any rescue opioid doses, resulting in a significantly reduced median rescue dose (6 versus 0 doses, p = 0.0017). Even when opioid doses were reduced due to PONV, Cohort A continued to exhibit significantly lower NRS scores. Conclusions Multimodal analgesia comprising the routine intravenous acetaminophen administration could be safe and effective after minimally invasive hepatectomy, without adverse effects regarding hepatic function.