Effect of single oral dose of sodium rabeprazole on the intragastric pH & volume in patients undergoing elective surgery.

BACKGROUND & OBJECTIVE While evaluating the effectiveness of drugs used for the prophylaxis of acid aspiration of gastric contents, the impact of duodeno-gastric reflux on gastric contents has not been studied earlier. This study was carried out to evaluate the effect of preanaesthetic oral administration of sodium rabeprazole on pH and volume of gastric contents in adult patients undergoing elective surgery by excluding cases contaminated with duodeno-gastric refluxate. METHODS The patients in group C (control) in the triple blind placebo controlled trial received placebo while group S sodium rabeprazole 20 mg orally at 2100 h, a night before elective surgery. Next day, gastric contents were aspirated with a large bore, multi-orifices gastric tube passed through an endotracheal tube placed blindly in oesophagus after tracheal intubation and analyzed for the presence of bile salts, pH and volume. The pH and volume of gastric contents were the primary and duodeno-gastric reflux secondary outcome measures of the study. RESULTS The pH and volume of group S-2 were 3.97+/-1.78 and 9.48+/-8.39 ml respectively compared with 1.90+/-0.47 and 19.60+/-18.56 ml of group C-2. Sodium rabeprazole, after excluding contaminated cases with duodeno-gastric refluxate, significantly increased the pH (P<0.001), decreased the volume of gastric contents (P<0.005) and the proportion of the patients (30.76 vs 2.63%) considered at risk compared with placebo (P<0.001) according to the criteria defined (pH < 2.5 and volume > 25 ml). Thirty nine samples (33.33%) out of 117 were contaminated with duodenal contents. Duodenogastric reflux significantly (P<0.001) affected pH and volume of gastric in both groups C-1 vs C-2 and S-1 vs S-2. INTERPRETATION & CONCLUSION Sodium rabeprazole 20 mg given orally a night before surgery provided adequate prophylaxis for acid aspiration syndrome at the time of induction of anaesthesia and duodeno-gastric reflux significantly affected both the pH and volume of gastric contents.