The effectiveness and duration of preoperative antacid therapy

Abstract

2 series of patients scheduled for elective surgery were studied. All patients in both groups received conventional premedication with subsequent general anesthesia administered by orthodox techniques. In addition, 1 series of patients received 10 ml of magnesium trisilicate mixture, given 10 to 15 min prior to the induction of anesthesia. Those patients in the non-antacid series served as the control group. Of the control series of 50 patients (mean pH=3.2), 24 produced a pH=2.5, which in 8 patients was contained in volumes 0.5 ml/Kg body weight. These 8 (16%) patients were thus potentially at risk for developing acid aspiration during emergence and/or recovery from anesthesia. Of the 100 patients who received preoperative antacid (mean pH=7.4) 2% produced samples of gastric aspirate at the conclusion of surgery with pH 2.5, but only 1 of these recorded a volume 0.5 ml/Kg. There was no correlation between pH and volume of gastric contents in either series.