Post-operative nausea and vomiting (PONV) is one of the leading causes of patient morbidity after laparoscopic bariatric surgeries. A wide variety of complications related to PONV has been described, such as prolonged length of stay (LOS) in hospital, unnecessary readmissions, delay in oral intake, and bad experience for patients. Although several antiemetic regimens have been tried so far in different studies, the incidence of PONV is not significantly lowered, and it seems that it is impossible to totally eliminate it. On the other hand, the implementation of Enhanced Recovery After Surgery (ERAS) has greatly reduced the incidence of PONV and LOS. Therefore, a combination of ERAS and multiple antiemetic regimens is currently used to reduce the incidence of PONV. Nevertheless, the optimal regimen has not been found yet, and many trials are conducting to find out the best antiemetic regimen. In this randomized clinical trial, we compare four different combined and single regimens alongside the implementation of ERAS to show which regimen is more effective.

After being approved by Iran National Committee for Ethics in Biomedical Research (IR.SBMU.MSP.REC.1399.784), a randomized clinical controlled trial was started with 130 patients in five groups. All the patients were proper candidates for laparoscopic bariatric surgeries, and structured informed consent was obtained from all participants.

All the operations were performed by board certified advanced laparoscopic surgeons in a minimally invasive educational center. All bariatric surgery was performed in our standardized institutional protocols as well as preoperative and postoperative care. Sleeve Gastrectomy (SG) surgeries were performed by using 44Fr Tubes.

To calculate the sample size in the clinical trial, we used the ANCOVA method with web-based tools. Twenty-six patients were estimated for each group. Patients were divided into five groups:

Group 1: Patients who did not receive any antiemetic during hospitalization (NA).

Group 2: Patients receiving metoclopramide alone (MA). Group 3: Patients who received ondansetron only. (OA) Group 4: Patients receiving a combination of metoclopramide and ondansetron (MO).

Group 5: Patients who received granisetron alone (GA). All patients were undergone ERAS protocols. In cases where the patient had PONV (including Group 1), intravenous Metoclopramide 0.2mg (Stat and BiD) was used as a rescue antiemetic.

To reduce the incidence of bias and confounding factors, all anesthetics and antiemetics used were provided from the same brand for each drug (see Appendix).

Patients with severe or moderate gastritis or duodenitis on esophagogastroduodenoscopy were excluded from the study, but patients with mild gastritis or positive rapid urease test on endoscopy, were treated for two weeks with three drugs of pentazole, amoxicillin, and metronidazole, and if the respiratory urease test was negative, they were included in the study and in refractory cases of H. Pylori, they were excluded. According to the American Society of Anesthesiologists (ASA) classification, patients with severe respiratory or cardiovascular problems (ASA III or higher) or a history of gastric or small bowel surgery were also excluded. Patients who underwent simultaneous cholecystectomy with bariatric surgery were also excluded.

Inclusion Criteria:

• BMI>40
• Only bariatric operations
• mild or moderate surgical risk
• without any previous gastrointestinal problems
• no previous gastrointestinal surgery

Exclusion Criteria:

• Moderate or severe gastritis or duodenitis
• GERD
• lack of H. Pylori eradication
• concurrent cholecystectomy
• Dissatisfaction during study

All the data and analytic works will be available for interested persons.

from February 2022

Everyone with verified institutional email.

After taking informed consent, patients enrolled in the groups. Each group had 26 members, and the subjects were unaware of which group they had been assigned. Also, the investigators weren't aware of the treatment assignment until the end of the trial.