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 15s over 145s using four different modalities: ECG, counted audible Doppler (AD) over 10s, 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 38weeks (27-41) and a mean weight of 2.78kg (0.82 to 4.76) with a median postnatal age of 3days (0-87) were studied. There was a mean difference of 0.69bpm (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 3s (1-45). The mean difference between DD-HR and ECG-HR was 5.37bpm (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 0.49bpm (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.