Protecting against the acid aspiration syndrome in adult patients undergoing emergency surgery.

This paper has studied the effect of i.v. cimetidine and ranitidine, given 1 h prior to anesthesia, on gastric volume and pH in three homogeneous groups undergoing emergency surgery. Group I (10 patients) received placebo, group II (20 patients) cimetidine 400 mg in saline solution, and group III (20 patients) ranitidine 150 mg in saline. Standardised premedication was administered and anesthesia induced. Immediately after tracheal intubation the stomach contents were aspirated and analysed for volume and pH. There were no significant differences in gastric volume among the three groups. However, treated patients had significantly elevated pH as compared with the control group and the number of patients at risk (pH < 2.5 and volume > 25 ml) was significantly smaller at 20% and 15%, respectively, than in the control group (40%). It is concluded that cimetidine 400 mg, and ranitidine 150 mg i. v., given about 70 min. prior to induction of anesthesia may decrease the risk of the acid aspiration syndrome in emergency operations.