Measurement of neonatal heart rate using handheld Doppler ultrasound.

OBJECTIVE: This pilot study aimed to determine whether handheld Doppler ultrasound is feasible and reliable for measuring neonatal heart rate (HR) when compared with ECG. SETTING: Stable newborns were recruited from the neonatal intensive care unit and postnatal ward between July 2014 and January 2015 at Royal North Shore Hospital, Sydney, Australia. INTERVENTIONS: Each newborn had their HR recorded every 15 s over 145 s using four different modalities: ECG, counted audible Doppler (AD) over 10 s, pulse oximetry (PO) and the Doppler display (DD). OUTCOME MEASURES: The correlation and variation between each modality and ECG. RESULTS: 51 newborns with a median gestational age of 38 weeks (27-41) and a mean weight of 2.78 kg (0.82 to 4.76) with a median postnatal age of 3 days (0-87) were studied. There was a mean difference of 0.69 bpm (95% CI -2.9 to +1.5) between AD-HR and ECG-HR with good correlation between modalities (r=0.94, p<0.01). The median time to achieve AD-HR was 3 s (1-45). The mean difference between DD-HR and ECG-HR was 5.37 bpm (95% CI -12.8 to +2.1) with moderate correlation (r=0.37, p=0.04). The mean difference between PO-HR and ECG-HR was 0.49 bpm (95% CI -1.5 to +0.51) with good correlation (r=0.99, p<0.01). The variability between AD-HR and ECG-HR decreased with decreasing weight. CONCLUSIONS: AD-HR correlates well with ECG-HR. Further research in the delivery room is recommended before using AD-HR in this area.