Heart-rate evaluation using fetal ultrasonic Doppler during neonatal resuscitation.

BACKGROUND

The 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-birthweight infants, and its efficacy during neonatal resuscitation, including cases of neonatal asphyxia.

METHODS

A three-lead electrocardiogram and fetal Doppler were used to measure resting heart rates in 100 newborns, including 48 preterm, low-birthweight infants, at 0 to 72 h 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, the fetal Doppler required a median time of 5 s, and electrocardiogram required a median time of 10 s (P < 0.001). During neonatal resuscitation, the heart rate was measured within 10 s in 18 of 21 cases (86%) and displayed with a median time of 5 s; this was measured in all neonatal asphyxia cases (9/9, 100%).

CONCLUSIONS

Fetal Doppler can measure heart rate in newborns accurately and rapidly and is useful for evaluating heart rate not only at rest but also during neonatal resuscitation, especially in asphyxia.