Acid-Base Status of Diabetic Mothers and Their Infants following Spinal Anesthesia for Cesarean Section

Abstract

Pregnancy in the diabetic patient is associated with increased hazard to mother and fetus. Cesarean section is frequently required in this high-risk group. The present authors, in a previous investigation, noticed lower umbilical pH values in infants of diabetic mothers having spinal anesthesia for cesarean section than in infants whose diabetic mothers received general anesthesia (7.20 vs. 7.28). The study reported here was designed to assess the effectiveness of the following measures in the administration of spinal anesthesia: 1) strict regulation of maternal blood glucose levels to maintain them between 80 and 90 mg/dl, 2) acute intravenous volume loading immediately before the induction of spinal anesthesia with a dextrose-free solution, and 3) avoidance of maternal hypotension during anesthesia. The purpose of such measures was to improve the neonatal acid-base values in this special group of patients.

Twenty parturients scheduled for elective primary or repeat cesarean section at term were selected at random. Ten were controlled insulin-dependent diabetic mothers (mean preoperative fasting blood glucose level, 86 ± 4 mg/dl). The other 10 were healthy nondiabetic women who served as control patients.

Two diabetic parturients were hospitalized three weeks before delivery for control of fasting blood glucose levels. Before surgery, however, fasting blood glucose levels were within normal limits (86 ± 4 mg/dl) in all the diabetic mothers.

Comparison of the two groups of mothers revealed no significant differences in maternal age, height, or gestational age. Systolic blood pressure did not exceed 130 torr in any parturient within 24 hours of operation, and none of the mothers had systolic pressures of more than 30 torr from baseline levels during anesthesia. The total amount of ephedrine administered varied from 10 to 30 mg and was not significantly different between the two groups.

There were no differences in the induction-delivery or uterine incision-delivery intervals between the two groups. The acid-base status of the mothers in both groups was normal at delivery. There were no significant differences in acid-base status or in blood-gas tensions between infants in the control and in the diabetic groups. Only one baby in the diabetic group had an Apgar score of less than 7 at one minute; the rest had Apgar scores greater than 7 at both one and five minutes.

The authors observed that strict control of maternal diabetes, avoidance of dextrose-containing solutions for acute maternal volume expansion before anesthesia, and prompt treatment of any decrease of maternal blood pressure will maintain neonatal acid-base status at control levels during spinal anesthesia and avoid the development of acidemia.