Low signal quality pulse oximetry measurements in newborn infants are reliable for oxygen saturation but underestimate heart rate

AimWe assessed the influence of system messages (SyMs) on oxygen saturation (SpO(2)) and heart rate measurements after birth to see whether clinical decision-making changed if clinicians included SyM data. MethodsThe heart rate and SpO(2) of term infants were recorded using Masimo pulse oximeters. Differences in means and standard deviations (SD) were calculated. Permutation corrected the nonrandom distribution and intersubject variation. SpO(2) and heart rate centile charts were computed with, and without, SyMs. ResultsPulse oximetry measurements from 117 neonates provided 28477 data points. SyMs occurred in 46% of measurements. Low signal quality accounted for 99.9% of SyMs. The mean SpO(2) was lower with SyMs (p<0.001), while the SpO(2) SD was similar to data without SyMs. The SpO(2) centile charts were approximately 2% lower with SyMs included, but they were not more dispersed. Mean heart rate was lower (p<0.001) and more dispersed (p<0.001) when a SyM occurred. The heart rate centile charts were lower, with increased variability, when SyMs were included. ConclusionA SyM occurred frequently during pulse oximetry in term infants after birth. SpO(2) measurements with low signal quality proved reliable for monitoring an infant's clinical condition. However, heart rate could be underestimated by low signal quality measurements.