Prospective, Double Blind, Placebo Control, Study of Acetaminophen iv on Hospital Length of Stay in Morbidly Obese Individuals Undergoing Elective Laparoscopic Sleeve Gastrectomy

Morbid obesity is defined as a body mass index (BMI: weight [kg] / height [m]2) ≥ 40 or ≥ 35 if associated with comorbidities, and it is widely prevalent, nationally and globally. Overweight or obese individuals have increased morbidity and mortality. Among the many available treatment options, surgical management of obesity has been shown to be the most reliably effective in achieving sustained weight loss and improvements in glycemic, lipidemic, and blood pressure control, and improves five and ten year survival in contrast to matched controls who did not have surgery. Various surgical approaches have been used to provide long-term control of morbid obesity and its associated comorbidities, including laparoscopic sleeve gastrectomy.

During a sleeve gastrectomy the greater curvature of the stomach is separated from the lesser curvature and antrum, thereby eliminating ~85% of the total stomach, including the grehlin-producing portion of the stomach. A common complication of the procedure is postoperative nausea and vomiting (PONV), occurring in nearly 80% of patients undergoing the procedure. Risk factors for PONV include: female sex, history of PONV or motion sickness, nonsmoking, younger age, general vs. regional anesthesia, use of volatile anesthetics and nitrous oxide, administration of postoperative opioids, duration of anesthesia, and type of surgery (including cholecystectomy, laparoscopic, and gynecological). At the individual level, PONV adversely impacts both patient satisfaction and quality of life scores. At the systems level, PONV is associated with increased length of stay (LOS) in the post-anesthesia care unit and hospital, and can result in increased costs.

Both pharmacological and surgical approaches have been studied in an effort to reduce the incidence of PONV in sleeve gastrectomy patients. Omentopexy was unsuccessful, and pharmacologic prophylaxis with two [dexamethasone + odansetron; dexamethasone + granisetron; aprepitant + odansetron; or three (dexamethasone + odansetron + haloperidol; antiemetic agents was more effective than a single agent (odansetron or granisetron) alone in decreasing both nausea and vomiting. Even with triple therapy, just over 50% of patients were nauseous and 20% vomited within the first 36 hours following surgery, and hospital LOS was unaffected. Thus, there is a pressing need for improved control of PONV in sleeve gastrectomy patients.

Acetaminophen (N-(4-hydroxyphenyl)acetamide; paracetamol) is a mild analgesic whose main, but not sole, mechanism of action is thought to arise from inhibition of the cyclooxygenase pathway; the intravenous (iv) formulation (acetaminophen iv; ACP-iv) received US Food and Drug Administration (FDA) approval in November 2010 but has been available in Europe since 2002. It is approved by the FDA for the management of mild to moderate pain as a single agent and the management of moderate to severe pain with adjunctive opioid analgesics. Recently, two meta-analyses have evaluated the use of ACP-iv in the postoperative period for its efficacy in preventing postoperative pain [45] or reducing PONV [46]. In the study by De Oliveria et al., ACP-iv administration was found to significantly reduce postoperative pain, opioid consumption, and PONV. Similarly, the study by Apfel and colleagues indicated that iv-ACP, when administered prophylactically, reduced PONV as a consequence of improved pain control. With direct relevance to sleeve gastrectomy patients, a retrospective analysis of patients undergoing bariatric surgery (sleeve gastrectomy or laparoscopic Roux-en-Y gastric bypass) found that ACP-iv administration reduced opiate consumption and hospital LOS.

The investigators hypothesize that administration of ACP-iv in the perioperative period will reduce hospital LOS in sleeve gastrectomy subjects and will be associated with a reduction in hospital costs. The secondary hypothesis is that administration of ACP-iv will reduce PONV and improve subject satisfaction scores in the same subject population.