Comparison of noninvasive techniques to measure blood pressure in newborns.

OBJECTIVE To compare blood pressure measurements in newborn infants using the flush method, pulse oximetry and oscillometry according to Doppler findings. METHODS Noninvasive blood pressure measurements were made using three techniques (flush method, pulse oximetry and oscillometry) in three groups of newborns: 15 normal term infants, 16 stable preterm infants, and 14 critically ill infants. All measurements were video recorded, edited separately, coded and analyzed independently by three neonatologists. RESULTS Fifty-seven measurements were made using each method. The flush method and pulse oximetry had a better correlation with Doppler findings than oscillometry (correlation coefficients: 0.89, 0.85, 0.71; p < 0.01). The difference between measurement means, their standard deviations and the 95% confidence intervals when compared with Doppler findings were: -5.2 ± 7.9 (-21.1:10.7) mmHg for the flush method; 0.4 ± 8.9 (-17.5:18.2) mmHg for pulse oximetry; and 6.4 ± 16.1 (-25.8:8.6) mmHg for oscillometry. The flush method had a better agreement with Doppler findings for the diagnosis of hypotension than oximetry and oscillometry. CONCLUSIONS The flush method and pulse oximetry seem to be useful techniques to measure systolic blood pressure in newborn infants; oscillometry had the poorest agreement with Doppler findings to detect hypotension.