EFFECTS OF ORAL RANITIDINE, FAMOTIDINE AND OMEPRAZOLE ON GASTRIC VOLUME AND PH AT INDUCTION AND RECOVERY FROM GENERAL-ANESTHESIA

We have studied, in 150 patients undergoing elective general surgery, the effect on gastric content of omeprazole 40 mg, ranitidine 300 mg a nd famotidine 40 mg, given orally the night and the morning before sur gery. Volume and pH of gastric content were measured at induction and recovery from anaesthesia. Gastric volumes did not differ between grou ps. The median gastric pH was lower with omeprazole compared with rani tidine and famotidine at intubation (5.11, 7.05 and 6.99, respectively ) (P < 0.001) and extubation (6.41, 6.98 and 6.96) (P < 0.001). The pr oportion of patients with gastric pH < 2.5 at induction was 40% for om eprazole, 12% for famotidine and 10% for ranitidine (P < 0.02); the pr oportion did not differ significantly at extubation.