Background: Inhaling of gastric contents in lower respiratory tract and larynx results in developing of pulmonary aspiration. The acidity of aspirate contents and its volume determines severity of aspiration and is major cause of post-anesthetic mortality.

Objective: To compare the effect of four drugs (ranitidine, IV ondansetron, metoclopramide, omeprazole and metoclopramide) in all possible four combinations, to decrease gastric fluid residual volume and gastric acidity in undergoing laparoscopic-cholecystectomy.

Design: It was a clinical randomized trial.

Study Settings: Trial was conducted at Department of Anesthesiology and ICU, Sheikh Zayed Hospital, Lahore, for a period of 6 months from 01-07-2019 to 31-12-2019.

Patients and Methods: A total of 308 patients from both the genders undergoing laparoscopic cholecystectomy were included in this study. Four equal groups were made by random division of patients. Group A: ranitidine & ondansetron, group B: ranitidine & metoclopramide, group C: omeprazole & ondansetron and group D: omeprazole & metoclopramide. Pre-anesthetic medicine was given to all the patients two hours before surgery. For assessing volume of gastric fluid and its pH, an oro-gastric tube was passed. An informed written informed consent was taken from all the patients.

Results: Mean age in this study was 36.40±9.15, 33.23±9.13, 36.82±9.37 and 36.57±9.49 years respectively for Group A,B,C and D. Aspirate had mean quantity of 12.56±5.60 ml/kg, 12.65±5.39 ml / kg, 13.68±5.76 ml/kg and 14.34±6.85 ml/kg and he aspirate mean pH was 2.56±0.55, 2.47±0.58, 2.51±0.57 and 2.45±0.58 respectively for group A,B,C and D. Among both the trial groups, this different was insignificant (p-value > 0.05) for both outcomes.

Conclusion: All the drug combinations had no significant difference. However, comparatively less pH and volume of gastric fluid was shown by combination of ranitidine plus ondansetron. Therefore, this combination is recommended before general anesthesia for reducing gastric fluid aspirate in patients undergoing surgery.

Keywords: Laparoscopic cholecystectomy, Omeprazole, Ranitidine, Metoclopramide, Ondansetron, gastric fluid acidity, pH, gastric fluid volume