Feasibility of handheld ultrasound to assess heart rate in newborn nursery

Background and objectives: Heart rate (HR) assessment is important during neonatal resuscitation. The most reliable ways of assessing HR at birth are pulse oximetry (PO) and/or electrocardiograph (ECG). However, delayed recording time due to poor perfusion or probe and electrode placement has been a concern. Point-of-care ultrasound (POCUS) provides a real-time instant view of the heart. The aim of this study was to look at the feasibility of POCUS in assessing the heart rate of stable, healthy, term neonates.

Methods: The study was approved by the institutional review board, and informed consent was obtained from the subject's mother. A real-time video image was obtained from the POCUS probe using the app on the smartphone. The principal investigator (PI) counted the heart beats for six seconds using a stopwatch, which was then multiplied by 10 to give the HR per minute. The assistant recorded the simultaneous HR using the PO. The HRs obtained from both methods were recorded and then compared using the Pearson correlation and Bland-Altman plot.

Results: A total of 30 HR observations were made using the POCUS and PO simultaneously. The correlation coefficient (r) was noted to be 0.75 with a p-value of <0.0001 for pairwise correlation. A strong agreement was noted between the two methods using Bland-Altman Plot.

Conclusion: We were able to demonstrate the feasibility of using handheld POCUS in assessing the HR of stable NB infants in the newborn nursery. A follow-up study is planned to evaluate its feasibility in the delivery room.