Antacids for obstetric patients.

The aspiration of regurgitated or vomited gastric contents is the most common cause of maternal deaths associated with anesthetics, causing an estimated 2 per cent of all maternal deaths in the United States. The incidence of aspiration is estimated to be one of every 430 patients who undergo cesarean section with general anesthesia. The pulmonary complications of aspiration are improved or avoided if the pH of the gastric contents is higher than 2.50. The oral administration of 30 c.c. of magnesium trisilicate has been shown to increase the pH of the gastric contents to above 2.50 in 100 per cent of treated patients, whereas only 60 per cent of the control group were found to have a pH above 2.50. Oral preoperative or predelivery antacid therapy may help to eliminate the morbidity and deaths secondary to aspiration and as such may be an adjuvant to, but not a substitute for, the safe management of the obstetric patient.