Duplex versus unguided pulsed Doppler measurements of right ventricular output in newborn infants.

Noninvasive measurement of pulmonary artery blood flow has widespread implications for management of newborn infants requiring intensive care. Using a precordial, unguided, single Doppler technique, we evaluated right ventricular output in 26 preterm and 16 term infants without cardiopulmonary problems and compared it with right ventricular output obtained by duplex Doppler scanning and left ventricular output measured by a suprasternal single Doppler approach. Weights ranged from 1,120 to 3,960 g and postconceptional ages from 29 to 42 weeks. Unguided measurements of left and right ventricular output and guided and unguided measurements of right ventricular output were highly correlated (r = +0.92 and +0.95 respectively, p less than 0.001). The precordial single Doppler technique offers a reliable noninvasive estimate of right ventricular output in preterm and term newborn infants.