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

Abstract

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 1 g 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 = .20). Opioid consumption was comparable between two groups. Group A utilized significantly less postoperative rescue antiemetics compared to group P (41% vs. 58%, P = .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.

Trial registration: ClinicalTrials.gov NCT03198871.

Keywords: Abdominal Surgery; Acetaminophen; Enhanced Recovery; Multimodal Analgesia; Postoperative Analgesia.

© The Author(s) 2021. Published by Oxford University Press on behalf of the American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Figures

Figure 1.

Consort flow diagram for the study population.

Figure 2.

After adjusting for age, gender, mental health medications, and intraoperative narcotic use, mixed model analysis showed no significant difference in pain scores at rest (P = .38) or with movement (P = 0.49) over time. ((A) Those treated with acetaminophen reported lower pain scores at rest (mean = 5.01, SE = 0.70) compared to the control group (mean = 5.86, SE 0.42) four hours post operatively. However, the acetaminophen group reported a higher mean increase in pain (mean = 0.03, SE 0.01) over time compared to the control group (mean = 0.02, SE = 0.01). ((B). Similar results were found with movement. The acetaminophen group reported a lower score at four hours post operatively (mean = 6.22, SE (0.91) compared to the control group (mean = 6.89, SE 0.54). Over time, the treatment group again reported a higher mean increase in pain (mean = 0.02, SE = 0.01) compared to the control group (mean = 0.01, SE = 0.01).