Assessment of neonatal heart rate immediately after birth using digital stethoscope, handheld ultrasound and electrocardiography: An observational cohort study
Abstract
The extent and initiation of cardiopulmonary resuscitation of neonates in the delivery room are largely guided by neonatal heart rate (HR), with current guidelines recommending the use of ECG for HR monitoring during resuscitation.1-3 Our aim was to determine if handheld ultrasound (HUS) or digital stethoscope (DS) could offer a novel method of quickly and effectively assessing HR in the delivery suite. Two physicians attended each delivery, one assessed the HR by stethoscope auscultation and the second assessed the HR using either HUS (Mortara, Signos RT Personal Ultrasound), DS (Littmann 3200, 3M, USA) or ECG (IntelliVue MP5, Philips, The Netherlands).
The time to achieve first HR and the HR recorded were noted, then when both modalities were recording a simultaneous HR was recorded. Each physician was blinded to the others recording modality during assessment.
The mean difference between stethoscope and ECG in the HR recorded was MINUS SIGN 10 beats per minute (bpm) (p=0.024), between stethoscope and HUS +5 bpm (p=0.4), and between stethoscope and DS +27 bpm (p=0.061). We found that the DS used in our study was unreliable at measuring HR in the delivery room, frequently not displaying any HR or displaying an HR significantly lower than the auscultated HR.
However, it should be highlighted that all infants assessed in our study were vigorous and often crying, which have been found previously to affect DS recording.4 It was noted that our ability to record HR on the HUS was limited by the fact that it is difficult to visually count contractions, especially at HR over 100 bpm. While an exact number of beats per minute was challenging to obtain, we could however appreciate cardiac contractility readily which would be valuable in neonatal resuscitation.
We conclude that ECG was the quickest method of recording HR in the delivery room compared with DS and HUS in our study. However, the traditional stethoscope remained the quickest method to obtain an HR when the time delay in applying ECG leads is taken into consideration.