Acoustic stimulation in hypoxic-ischemic encephalopathy: heart rate analysis.

Two groups of 30 term newborns (normal and anoxic) were analyzed to study the influence of anoxia in the heart rate. The experiment consisted in a polygraphic EEG register before, during and after an acoustic stimulus. In basal conditions of active sleep, the heart rate in the asphyctic newborn was higher than in the normal group. The acoustic stimulation caused a transitional tachycardia. The variability of the heart rate was smaller in the asphyctic group. The basal heart rate varied in relation to the grade of Hypoxic-Ischemic Encephalopathy (HIE) and there was also a difference in the capacity of response to acoustic stimulation between the moderate HIE group and the normal group.