INFLUENCE OF PREOPERATIVE GASTRIC ASPIRATION ON THE VOLUME AND pH OF GASTRIC CONTENTS IN OBSTETRIC PATIENTS UNDERGOING CAESAREAN SECTION

Aspiration of gastric contents, the most common anaestheticcause of maternal mortality, is decreased by emptying of thestomach and the use of antacids and H₂-receptor antagonists.One hundred and eighty-three mothers presenting for emergencyCaesaren section were allocated to three groups. In group 1,the stomach was emptied before operation via an orogastric tubeand thereafter 30 ml of sodium citrate 0.3 mol litre^–1was ingested 5–15 min before induction of general anaesthesia(our usual practice). Group 2 received only 30 ml of sodiumcitrate 0.3 mol litre^–1. Group 3 received ranitidine 50mg i.v. before operation, 5–15 min before induction ofanaesthesia, in addition to sodium citrate. Our results showthat preoperative gastric emptying with an orogastric tube followedby sodium citrate is preferred if anaesthesia should be induced15–20 min later. However, the use of ranitidine and sodiumcitrate is preferred at subsequent times. Although our datashow that preoperative gastric emptying decreased the mean intragastricvolumes before Caesarean section, the number of patients atrisk of acid aspiration was not reduced. In view of these findingsand the unpleasantness of orogastric intubation, we suggestthat routine preoperative gastric aspiration via an orogastrictube is not justified, although the manoeuvre should still beused following a recent meal.