INHIBITION OF GASTRIC-ACID SECRETION IN THE INTENSIVE-CARE UNIT AFTERCORONARY-ARTERY BYPASS GRAFT - A PILOT CONTROL STUDY OF INTRAVENOUS OMEPRAZOLE BY BOLUS AND INFUSION, RANITIDINE AND PLACEBO

We have investigated the acid inhibitory efficacy of omeprazole and ra nitidine in patients in the intensive care unit. Following coronary ar tery bypass grafts (CABG), 41 patients were randomly allocated to rece ive placebo, ranitidine 50 mg i.v. every 8 h, omeprazole 80 mg loading dose and then 40 mg every 8 h, omeprazole 80 mg loading dose and then 40 mg every 8 h by i.v. bolus or omeprazole 80 mg i.v. loading dose a nd then 40 mg every 8 h by i.v. infusion. Gastic aspirate samples were collected before administration of the study drug and then continuous ly in hourly aliquots for a minimum of 20 h for measurement of volume, pH titratable acidity and pepsin. The pretreatment pH values in patie nts randomised to the two omeprazole groups were notably lower than th ose in the placebo and ranitidine groups. This rendered comparison of pH changes impossible. Gastric aspirate pH significantly increased in the two omeprazole groups. Volume of aspirate was significantly decrea sed in the two omeprazole groups (but not in the ranitidine group) com pared with placebo. There were no significant differences in 24-h acid output, total pepsin activity or mean 24-h pH between the groups, and there were no significant differences in haematological, renal or liv er function tests between the groups. Although intravenous omeprazole increased the pH and reduced the volume of gastric secretions, it did not, in the doses used, fully inhibit gastric secretion.