Intravenous acetaminophen in bariatric surgery: effects on opioid requirements

Background: Opioids are commonly used after bariatric surgery for pain control because of their potent analgesic effects. Nevertheless, the morbidly obese patient has increased risk for developing adverse effects produced by opioids (such as sedation, apnea, hypoxemia, ileus, and vomiting). Intravenous acetaminophen (IVA) has been evaluated in some specialties showing a reduction in opioid consumption. The purpose of this study was to evaluate the effect on opioid consumption when IVA is administered in bariatric surgery patients. Material and methods: A retrospective study was performed in patients who underwent bariatric surgery. Group A included those patients who received IVA perioperatively and group B those who did not. The amount of opioids administered was calculated and compared for each group. Results: Group A included 38 cases (44.7%) and group B included 47 cases (55.3%). A comparison was performed in terms of age (P = 0.349), body mass index (P = 0.311), gender (P = 0.890), American Society of Anesthesiologist score (P = 0.438), total surgical time (P = 0.497), perioperative complications (P = 0.786), number of procedures per surgeon (P = 0.08), and type of surgical procedure (P <= 0.01). Group A had a mean 24-h total opioid dose of 99.5 mg, whereas group B of 164.6 mg (P = 0.018). Group A received 39.5% less opioids than group B. A post hoc analysis determined a statistical power of 0.74. Conclusions: IVA used perioperatively can decrease opioid consumption in patients after bariatric surgery. Randomized trials are needed to corroborate these results. (C) 2015 Elsevier Inc. All rights reserved.