Journal of Applied Physiology, Vol 79, Issue 1 63-65, Copyright © 1995 by American Physiological Society
Effects of neuromuscular blockade on fetal heart rate variability: a power spectrum analysis
O. Sibony, J. P. Fouillot, D. Luton, J. F. Oury and P. Blot
Departement de Perinatologie, Hopital Robert Debre, Paris, France.
Spectral analysis of fetal heart rate variability allows quantitative
determination of the main components that affect this variability. The
physiological significance of these components is unclear; however,
movements appear to contribute to variability. We studied six fetuses in
which immobility required for in utero magnetic resonance or invasive fetal
procedures was achieved by fetal intravascular injection of curare between
32 and 36 amenorrhea weeks. For each fetus, we compared spectral density
parameters of heart rate variability. After curare administration, mean
spectrum power was halved. We did not observe a larger significant decrease
in any (very low, low, or high) frequency band. The other parameters of
spectral analysis of variability were unaltered. Fetal movements accounted
for a significant proportion of human fetal heart rate variability but did
not constitute a unique frequency component.
