Control of Gastric Acidity by Glycopyrrolate Premedication in the Parturient

The effect of premedication with the anticholinergic quaternary ammonium compound, glycopyrrolate (0.4 mg), on gastric juice pH was investigated in 23 parturients scheduled for elective cesarean section under general anesthesia, and the results were compared to a control group of 15 nonpremedicated obstetric patients and 25 parturients premedicated with atropine (0.6 mg). In the nonpremedicated control group, the mean gastric juice pH was 2.36 (SE +/- 0.23), 66% having a pH less than the critical level of 2.5. Premedication with atropine did not significantly increase the gastric pH, while in those premedicated with glycopyrrolate, the mean pH increased to 3.7 (+/- 0.35), and the incidence of pH less than the critical level dropped to 34%. The effect of glycopyrrolate on gastric juice pH was significantly increased when the premedication-induction time was prolonged to 60 to 120 minutes. It was concluded that glycopyrrolate premedication can be used in the parturient as an additional measure to safeguard against acid-aspiration syndrome.