317 EFFECT OF GLUCOSE ADMINISTRATION ON FETAL BREATHING ACTIVITY (FBA) IN THE BABOON - EPOCH ANALYSIS RESULTS

Abstract

The relationship of breathing to other fetal activities was studied in 8 chronically catheterized pregnant baboons at 138-155 days of gestation following i.v. infusion of 25g of glucose to the mother. No significant changes in fetal heart rate (FHR), FHR variability and fetal or maternal blood pressure were observed during the infusion period.

A computer based epoch analysis method was used to automatically detect fetal breaths from a tracheal fluid pressure signal, distinguish episodes of breathing activity from apnea and generate parameters to characterize FBA. Although the number of epochs of FBA was essentially unchanged and breathing rate and variability increased slightly with glucose infusion, significant decreases in other FBA parameters were observed: mean epoch duration decreased from 13.7 to 12.4 sec; median number of breaths per epoch fell from 12 to 6 while the % of time spent in FBA dropped from 20.6% to 10.8%. Finally, mean breathing amplitude also decreased from −8.3 to −6.7 mmHg.

These results were unexpected. In human fetuses increases in plasma glucose have been associated with increased FBA. Our results may reflect variation among primate species. Nonetheless we noted that the direction of change in FBA parameters was consistent among all animals and suggests a need for study of the effect of maternal metabolic state on FBA.

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