Intravenous omeprazole in critically ill patients: a randomized, crossover study comparing 40 with 80 mg plus 8 mg/hour on intragastric pH.

OBJECTIVE: To compare intravenous omeprazole 40-mg single dose with 8 mg/hr after an 80-mg bolus injection on 24-hr intragastric pH in intensive care unit (ICU) ventilated patients. DESIGN: Prospective, randomized crossover study. SETTING: A 42-bed medicosurgical ICU in a university hospital PATIENTS: Medicosurgical ventilated patients at risk of gastrointestinal bleeding. INTERVENTIONS: After baseline determination of intragastric pH, patients were randomly allocated to have a 40-mg iv omeprazole bolus injection (arm I) or 80 mg bolus, followed by 8 mg/hr continuous infusion for 24 hrs (arm II). After a 24-hr washout period, the opposite regimen was given in a crossover design. Intragastric pH was determined at regular intervals during the treatment period. RESULTS: In ten patients completing the protocol, the intragastric pH was similar for the two regimens for the first 12 hrs. The area under the pH curve was 5.51 +/- 0.48 for arm I compared with 6.02 +/- 0.33 for arm II (NS). Time to reach a pH of 4 or 6 was not significantly different for the two regimens. Time spent with a pH greater than 4 and 6 for the first 12 hrs was 10.11 +/- 1.14 and 8.31 +/- 1.16 hrs vs. 10.11 +/- 0.75 and 7.43 +/- 1.19 hrs for arm I and arm II, respectively (NS). When the first 24 hrs are considered, the area under the pH curve was 5.17 +/- 0.49 for arm I vs. 6.36 +/- 0.25 for arm II (p <.05). Time spent with a pH greater than 4 and 6 was 17.2 +/- 2.4 hrs and 12.63 +/- 2.22 vs. 23 +/- 0.41 and 19.48 +/- 1.63 in arm I and arm II, respectively (p <.05 and.01). An intragastric pH above 6 for all determinations was only observed in arm II. CONCLUSIONS: In critically ill patients, intravenous omeprazole 40 mg single dose is as effective as 8 mg/hr after an 80-mg bolus injection on mean intragastric pH, time spent with a pH greater than 4 and 6, but only for the first 12 hrs. If an intragastric pH greater than 6 has to be maintained for 24 hrs in all patients, an 80-mg bolus followed by 8 mg/hr iv omeprazole is to be given. Our data suggest that in several critically ill patients, a single 40-mg iv omeprazole bolus injection may be able to achieve stress ulcer prophylaxis and that 40 mg twice daily should be compared with 8 mg/hr after an 80-mg bolus injection in bleeding ulcers.