EFFECT OF ERYTHROMYCIN ON GASTRIC-MOTILITY IN MECHANICALLY VENTILATED CRITICALLY ILL PATIENTS - A DOUBLE-BLIND, RANDOMIZED, PLACEBO-CONTROLLED STUDY

Objective: To document the action of erythromycin on gastric emptying and motility in mechanically ventilated patients. Design: Crossover, double-blind, randomized, placebo-controlled study. Setting: General intensive care unit in a university hospital. Patients: Ten patients, mechanically ventilated, in a stable hemodynamic condition. Interventions: Erythromycin (200 mg iv over 30 mins) and placebo were infused at midmorning, on two consecutive days, in a random order. Pressure changes in the gastric antrum were recorded by means of a multilumen manometric tube (perfused catheter technique) over a period of 300 mins, beginning with the institution of the erythromycin or placebo infusion. Gastric emptying was simultaneously assessed by the kinetics of the absorption of acetaminophen delivered into the stomach (1 g with 20 mL of water) immediately before the infusion. Measurements and Main Results: Motility was quantified by determining the number of contractions, the amplitude of contractions, and the Motility Index (Motility Index = natural logarithm [sum of amplitude x number of contractions] + 1). Comparison between placebo and erythromycin was made for the first hour after the infusion and for the whole recording session. The maximal acetaminophen concentration, the time to reach the peak acetaminophen concentration, and the area under the concentration-time curve at 60 mins were obtained from serial determinations of plasma acetaminophen concentrations. Compared with placebo, the mean number of contractions (104 +/- 34 vs. 5 +/- 8; p = .003), the mean amplitude of contractions (52 +/- 16 vs. 20 +/- 17 mm Hg; p = .005), and the Motility Index (13.06 +/- 0.95 vs. 4.45 +/- 3.54; p = .004) were significantly increased during the first hour after erythromycin infusion compared with placebo. Number of contractions (p = .017) and Motility Index (p < .001) after erythromycin infusion remained significantly higher when values throughout the whole recording session were considered. The following data were noted after erythromycin was infused: a) the time to reach the peak acetaminophen concentration was shorter (32 +/- 8 vs. 171 +/- 93 mins; p = .007); b) the maximal acetaminophen concentration was higher (22.09 +/- 6.23 vs. 5.38 +/- 3.80 mu g/mL; p = .007); and c) the area under the concentration-time curve at 60 mins increased markedly (730 +/- 269 vs. 72 +/- 42 mu g/min/mL; p = .002) as compared with placebo. Conclusion: In mechanically ventilated patients, intravenous erythromycin (200 mg over 30 mins) increases indices of antral motility and accelerates gastric emptying as assessed by the kinetics of acetaminophen absorption.