Open AccessParasympathetic nervous system response to acidosis: Evaluation in an experimental fetal sheep model
Author(s) -
Ghesquière Louise,
De Jonckheere Julien,
Drumez Elodie,
Sharma Dyuti,
Aubry Estelle,
Deruelle Philippe,
Storme Laurent,
HoufflinDebarge Véronique,
Garabedian Charles
Publication year - 2019
Publication title -
acta obstetricia et gynecologica scandinavica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.401
H-Index - 102
eISSN - 1600-0412
pISSN - 0001-6349
DOI - 10.1111/aogs.13515
Subject(s) - medicine , acidosis , fetus , heart rate , anesthesia , autonomic nervous system , cardiology , metabolic acidosis , blood pressure , pregnancy , biology , genetics
Heart rate variability and fetal heart rate decelerations are impacted by parasympathetic function and reflect acid‐base status. Our team developed a new heart rate variability index, the fetal stress index ( FSI ), which has lower interindividual variability and higher sensitivity for detecting fluctuations in parasympathetic nervous system activity. The aim of this study was to explore the ability of the FSI to predict fetal acidosis in a fetal sheep model. Material and methods Repeated 1‐minute total umbilical cord occlusions ( UCO s) were performed every 2.5 minutes over 3 hours to generate fetal acidosis mimicking that which occurs during labor and contractions. Fetal hemodynamic parameters, blood gas, the FSI and the magnitude (from the beginning to the nadir) of the fetal heart rate deceleration were recorded at regular intervals. The data were analyzed over three time intervals because of variation in the duration of the experiments: period A (first 12 UCO s), period B (middle 12 UCO s) and period C (last 12 UCO s). Results Nine experiments were performed. Acidosis was progressive with a significant difference between the pH , lactate levels and base deficit values for the three periods of occlusion ( P < 0.05). Both FSI and the magnitude of fetal heart rate decelerations gradually increased during the UCO s and both differed significantly between periods A and C ( P = 0.0008 for FSI and P = 0.003 for deceleration). Conclusion This experimental protocol allowed the development of progressive acidosis in a good model of the physiology of labor. Parasympathetic nervous system activity increased during acidosis and could be measured using our index, the FSI , and the magnitude of fetal heart rate decelerations.