Gastric volume in early pregnancy: effect of metoclopramide.

This study was designed to ascertain whether gastric volume in early pregnancy is unduly large, and to determine whether preanesthetic administration of metoclopramide decreases this volume. Gastric pH and volume were measured following induction of general anesthetics in 20 nonpregnant surgical patients; 62 patients undergoing therapeutic abortion (mean gestational age, 15 +/- 3 weeks); and in 31 patients undergoing therapeutic abortions who received 10 mg metoclopramide intravenously, 15 to 30 min before anesthesia. Gastric volume was the same in the pregnant and nonpregnant control patients; in this former group, volume was not related to gestational age. In the nonpregnant control group, mean pH was lower, and there were more patients with a pH less than 2.5 than in the other groups; metoclopramide had no effect on pH. Treatment with metoclopramide resulted in significantly lower mean gastric volume (15 vs. 28 ml) and in significantly fewer patients with a gastric volume exceeding 25 ml (13% vs. 51%). Early pregnancy (less than 20 weeks gestation) confers no additional anesthetic hazard due to large gastric volume or low pH. Our data suggest that preanesthetic administration of metoclopramide may be beneficial in decreasing the risk of aspiration pneumonitis.