Heart rate evaluation using fetal ultrasonic Doppler during neonatal resuscitation.

BACKGROUND: Our objective of the present study was to verify the speed and accuracy of fetal ultrasonic Doppler (fetal Doppler) in measuring heart rate of newborns at rest, including preterm, low birth weight infants, and its efficacy during neonatal resuscitation, including cases of neonatal asphyxia. METHODS: A 3-lead electrocardiogram and fetal Doppler were used to measure resting heart rates in 100 newborns, including 48 preterm, low birth weight infants, at 0 to 72 hours after birth. Times to display heart rate were compared between electrocardiogram and fetal Doppler by the Bland-Altman analysis and Wilcoxon signed-rank test. The time required for the fetal Doppler to measure heart rate during neonatal resuscitation was also assessed. RESULTS: In 100 newborns, the mean error of the resting heart rate in 1,293 measurement points was 0.07 beats/min. To display the heart rate, fetal Doppler required a median time of 5 seconds, and electrocardiogram required a median time of 10 seconds (p < 0.001). During neonatal resuscitation, the heart rate was measured within 10 seconds in 18 of 21 cases (86%) and displayed with a median time of 5 seconds; this was measured in all neonatal asphyxia cases (9/9, 100%). CONCLUSIONS: Fetal Doppler can accurately and rapidly measure heart rate in newborns and is useful for evaluating heart rate not only at rest, but also during neonatal resuscitation, especially in asphyxia.