Validation of spontaneous assessment of baroreceptor reflex sensitivity and its relation to heart rate variability in the ovine fetus pre- and near-term.
Assessment of baroreceptor reflex sensitivity (BRS) in the ovine fetus provides insight into autonomic cardiovascular regulation. Currently, assessment of BRS relies on vasoactive drugs, but this approach is limited by feasibility issues and by the nonphysiologic nature of the stimulus. Thus we aimed to validate the method of spontaneous BRS assessment against the reference method of using vasoactive drugs in preterm (0.76 gestation, n = 16) and near-term (0.86 gestation, n = 16) chronically instrumented ovine fetuses. The BRS measures derived from the spontaneous and reference methods correlated at both gestational ages (R = 0.67 +/- 0.03). The sequence method of spontaneous BRS measures also correlated both to the root mean square of standard deviations (RMSSD), which is a measure of fetal heart rate variability reflecting vagal modulation (R = 0.69 +/- 0.03), and to fetal body weight (R = 0.65 +/- 0.03), which is a surrogate for growth trajectory of each fetus. The methodology presented may aid in developing new models to study BRS and cardiovascular control in ovine fetus in the last trimester of pregnancy.
Department of Obstetrics and Gynaecology, Lawson Health Research Institute, The University of Western Ontario, 268 Grosvenor Street, London, ON N6A 4V2, Canada. mfrasch@uwo.ca
Martin G
MG
Frasch
Thomas
T
Müller
Mark
M
Szynkaruk
Matthias
M
Schwab
D000818:Animals; D017704:Baroreflex / Q000187:drug effects / Q000502:physiology*; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D005260:Female; D005318:Fetal Heart / Q000187:drug effects / Q000196:embryology* / Q000502:physiology; D005323:Fetal Monitoring / Q000379:methods*; D005865:Gestational Age; D006340:Heart Rate, Fetal / Q000187:drug effects / Q000502:physiology*; D011247:Pregnancy; D015203:Reproducibility of Results; D012756:Sheep / Q000196:embryology* / Q000502:physiology; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014665:Vasodilator Agents / Q000494:pharmacology
D014662:Vasoconstrictor Agents; D014665:Vasodilator Agents