COMPARATIVE EFFECTS OF PREMEDICATION WITH DIAZEPAM, RANITIDINE, SODIUM-CITRATE AND ENPROSTIL ON GASTRIC-JUICE PH AND VOLUME

A study was designed to assess the efficacy of oral premedication with diazepam or enprostil in preventing the gastric aspiration syndrome in fasted patients scheduled for elective surgery, and to compare the results with those obtained with ranitidine and sodium citrate. The study included 120 consecutive patients undergoing urological or plastic surgery, randomly assigned to four groups of 30. Two hours before anaesthesia, the patients from three groups were given, with 30 ml of water, either 10 mg diazepam, or 150 mg ranitidine, or 35-mu-g enprosil. Those in the fourth group were given 30 ml of 0.5 M sodium citrate, ten minutes before induction. Anaesthesia consisted in the administration of thiopentone, fentanyl, vecuronium and nitrous oxide in oxygen. After endotracheal intubation, a gastric tube was inserted. The stomach fluid content was completely aspirated, and then again 60 and 120 min after induction, as well as at the end of surgery. Age, weight and duration of surgery were comparable in the four groups. Mean pH in the diazepam group was much lower than that in the other groups, both just after induction (2.3 +/- 1.54; p < 0.001 vs. ranitidine and sodium citrate; p < 0.01 vs. enprostil) and at the end of surgery (3.2 +/- 2.03; p < 0.01 vs. ranitidine and sodium citrate; p < 0.05 vs. enprostil). There was more than 0.4 ml.kg-1 gastric juice in the sodium citrate group. Immediately after induction, 22 % of patients in the diazepam group were considered to be at risk from gastric aspiration (pli < 2.5, and volume above 0.4 ml.kg-1), as opposed to 6 %, 4 % and none in the enprostil, ranitidine and sodium citrate groups respectively. It was concluded that oral diazepam premedication did not protect against the risk of gastric aspiration in fasted patients scheduled for elective surgery.