The Effect of Scheduled Intravenous Acetaminophen in an Enhanced Recovery Protocol Pathway in Patients Undergoing Major Abdominal Procedures: A Prospective, Randomized, and Placebo-Controlled Clinical Trial.

Objective Enhanced recovery protocols (ERPs) utilize multi-modal analgesia regimens. Individual regimen components should be evaluated for their analgesic efficacy. We evaluated the effect of scheduled intravenous (IV) acetaminophen within an ERP on analgesia and recovery after a major abdominal surgery. Design This study is a prospective, randomized, double-blinded clinical trial. Setting The study setting was a tertiary care, academic medical center. Subjects Adult patients scheduled for elective major abdominal surgical procedures. Methods Patients in group A received 1g IV acetaminophen, while patients in group P received IV placebo every six hours for 48 hours postoperatively within an ERP. Pain scores, opioid requirements, nausea and vomiting, time to oral intake and mobilization, length of stay, and patient satisfaction scores were measured and compared. Results From 412 patients screened, 154 patients completed the study (Group A: 76, Group P: 78). Primary outcome was the number of patients with unsatisfactory pain relief, defined as a composite of average Numeric Rating Scale (NRS) scores above 5 and requirement of IV patient-controlled analgesia for pain relief during the first 48 hours postoperatively, and was not significantly different between the two groups (33 (43.4%) in group A versus 42 (53.8%) patients in group P, p=0.20). Opioid consumption was comparable between two groups. Group A utilized significantly less postoperative rescue antiemetics compared to group P (41% vs. 58%, p= 0.02). Conclusions Scheduled administration of IV acetaminophen did not improve postoperative analgesia or characteristics of postoperative recovery in patients undergoing major abdominal surgery within an ERP pathway.