Estimating Neonatal Oxygen Consumption from Heart Rate

ABSTRACT The relationship between heart rate (HR) and oxygen consumption (V̇o2) has been investigated in a sample of 20 low‐risk, term neonates aged 14–48 hrs. Repeated, simultaneous measurements of HR and V̇o2 were performed on each neonate during each of three epochs ordered by increasing level of activity. A robust linear relationship was found between HR and V̇o2, with an average correlation of.90. Substantial variation was observed across individuals in the slope of the HR‐V̇o2 regression line. This variation was curvilinearly related to ponderal index (PI), with low PI neonates having the shallowest and steepest slopes. These findings suggest that HR may provide a flexible, non‐restrictive means of estimating neonatal V̇o2 but that the impact of prenatal growth history and postnatal growth performance on the estimation of V̇o2 from HR merits further investigation.