IV Acetaminophen for Post-Operative Pain Management in Enhanced Recovery After Surgery (ERAS) Population

Number of patients with unsatisfactory pain relief defined as average visual analog scale (VAS) more than 5 with or without requirement of IVPCA for pain relief during the first 48 hours postoperative period will be compared between the two groups and form the primary outcome for the study. Postoperative pain intensity will be measured by Visual Analog Scale (VAS) with 0- being no pain and 10-being maximum pain and the analgesic efficacy in both groups will also be evaluated by the amount of total narcotic consumption (measured with IV morphine equivalent doses of analgesics used to provide pain relief).

In response to an increased focus on improving patient outcomes and satisfaction with surgical care, a growing body of clinical evidence has recently been dedicated to enhanced recovery after surgery (ERAS) protocols. These evidence-based perioperative pathways aim to optimize patients undergoing surgery in the preoperative, intraoperative, and postoperative periods. ERAS protocols have incorporated the use of multimodal analgesia to minimize the use of intra- and postoperative opioid analgesics. Lidocaine, ketamine, magnesium, gabapentin, acetaminophen and non-steroidal anti-inflammatory drugs are some of the adjuvant analgesics used in combination with regional blocks to optimize analgesia and recovery. Multimodal analgesia has dependably been shown to significantly reduce postoperative opioid requirements as well as opioid-related side effects such as postoperative nausea and vomiting. Both oral and intravenous acetaminophen preparations have been shown to be useful adjuvants in multimodal analgesia. Intravenous acetaminophen has been of interest for its utility in post-surgical patients, who have not yet been cleared for oral intake. Intravenous acetaminophen should also be preferred over oral acetaminophen in patients after major abdominal surgery where absorption of medications given through oral route is erratic. Although the efficacy of intravenous acetaminophen as a postoperative pain adjunct is known, its exact role in ERAS protocols and non-narcotic multimodal analgesic regimens for major abdominal surgery has not been studied in randomized clinical trials to define its efficacy. The primary goal of this study is to assess the utility of a postoperative intravenous acetaminophen dosing schedule in minimizing postoperative pain, opioid consumption and opioid-related side effects. We also aim to study overall patient satisfaction and cost-effectiveness (direct and indirect costs) of this regimen as part of ERAS protocol at a large tertiary medical center.

Eligibility Criteria:
Inclusion Criteria:

* Male or Female
* 18 years of age or older
* patients scheduled for elective colorectal, pancreatic, and other major abdominal procedure.
* Patient consent will be obtained preoperatively for eligible study participants.

Exclusion Criteria:

* Patients who refuse to participate in the study or part of any other enhanced recovery after surgery (ERAS) research protocol.
* Patients with a documented allergy to acetaminophen.
* Chronic alcoholism
* Hypovolemia
* Chronic malnutrition
* Preoperative renal insufficiency (creatinine clearance less than or equal to 30ml/min) or hemodialysis
* Patients with a history of hepatic impairment, history of hepatic impairment or active hepatic disease
* severe chronic pain condition that required daily preoperative opioid dependence
* Patients with pre-existing dementia and/or other neuropsychiatric conditions impeding accurate assessment of pain scores or other study measures will be excluded.