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

Abstract

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. 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 72h after birth. Times to display heart rate were compared between electrocardiogram and fetal Doppler by the Bland-Altman analysis and Wilcoxonsigned-ranktest. The time required for the fetal Doppler to measure heart rate during neonatal resuscitation was also assessed. 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 5s, and electrocardiogram required a median time of 10s (P < 0.001). During neonatal resuscitation, the heart rate was measured within 10s in 18 of 21 cases (86%) and displayed with a median time of 5s; this was measured in all neonatal asphyxia cases (9/9, 100%). 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.