Effect of clmetidine on reduction of gastric secretion and pH in adult patients undergoing elective surgery and its impact on aspiration risk

ABSTRACT

Aspiration of gastric contents is rare, but serious and life threatening complication of general anaesthesia. Its severity depends upon the pH and volume of gastric contents. This study was conducted to evaluate the effect of pre-anaesthetic administration of oral Cimetidine on pH and volume of gastric contents in 116 adult inpatients of either sex, American Society of Anaesthesiologists physical status I-II, and aged 15-70 years. The patients in Group C [Control] received Placebo while Group T [Cimetidine 800 mg] orally at 9 PM, 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 analysed for the presence of bile salts, pH and volume. Thirty-two samples [28.31%] out of 113 were contaminated with duodenal contents. Duodenogastric reiluxate significantly affected both the pH and volume of gastric contents in both groups. Cimetidine, after excluding contaminated cases either with duodenogastric refluxate or blood, did not significantly increase the pH [p=0.1221], decrease the volume of gastric contents [p=0.0816] and the proportion of the patients [25.64% versus 23.80%] considered [at risk] compared with Placebo [p=1.0000] according to the criteria defined [pH 25 ml]. Cimetidine 800 mg given orally at 9 PM did not provide adequate prophylaxis for acid aspiration syndrome at the time of induction of anaesthesia