Comparative Study between Ondansetron and Dexamethasone for Preventing Postoperative Nausea and Vomiting after laparoscopic Cholecystectomy

BACKGROUND Postoperative nausea and vomiting (PONV) have been described as the "big little problem"(1,2) for anaesthesiology for laparoscopic surgery. Commonest cause of morbidity after aesthesia and surgery are pain and postoperative nausea vomiting.(3,4,5) METHODS Institutional ethical committee clearance and written informed consent were obtained from 60 female patients of American Society of Anaesthesiologists physical status I and II, aged between 18 to 65 years, weighing about 50-60 Kg., height 150 to 160 cm, scheduled for laparoscopic cholecystectomy (duration < 90 minutes) under general anaesthesia in this prospective, randomised, double blind controlled study. Patients coming to operation theatre were divided by computer generated randomization in to two groups of 30 each, Group-A (n=30) and Group-B (n=30). A person, who was blind to the randomisation schedule, was administered the study drug 1 minute prior to other I.V. drugs. One of the following regimens, for Group A patients: Ondansetron 4 mg in 2 ml or for Group B patients: Dexamethasone 8 mg in 2 ml were administered. After preoxygenation, general anaesthesia was administered, pneumoperitoneum created, laparoscopic cholecystectomy done, and anaesthesia reversed. For post-operative analgesia Paracetamol (1000 mg) I.V. was administered. All patients were observed post operatively by noting vital signs and complications, if any. All episodes of PONV (nausea, vomiting, retching) were recorded for 12 hrs post operatively. Rescue drug Inj. Metoclopramide 10 mg I.V. was given, if required. All data from each patient was obtained and tabulated. RESULTS The age, weight, height, ASA status and duration of surgery of the patients included in study group (p=0.05) were comparable and there was no significant statistical difference among the data collected during the study. Incidence of nausea is higher in both groups in the first hour though it is not statistically significant. Within 3-6 hours, patients receiving Dexamethasone had higher incidence of nausea, but it is not statistically significant. Incidence of retching is higher in both groups in the first hour. It is not statistically significant. Vomiting was more in the first 3 hours in both groups. It was not statistically significant. Need for rescue drug (Inj. metoclopramide 10 mg I.V.) was similar in both groups. CONCLUSIONS Ondansetron is as effective as Dexamethasone in reducing the incidence of nausea and vomiting in post-operative period of laparoscopic cholecystectomy and has minimal side effects.