CONGENITAL HEART-DISEASE WITH DUCTAL-DEPENDENT SYSTEMIC PERFUSION - DOPPLER ULTRASONOGRAPHY FLOW VELOCITIES ARE ALTERED BY CHANGES IN THE FRACTION OF INSPIRED OXYGEN

Background: An unfavorable balance in systemic and pulmonary perfusion may occur in neonates with ductal-dependent systemic perfusion while being treated with prostaglandin E(1) before surgical palliation or tr ansplantation. At our institution, we adjust the fraction of inspired oxygen, with supplemental nitrogen if needed, to control pulmonary vas cular tone and maintain systemic oxygen saturations near 75%. Methods: We performed a noninvasive Doppler ultrasound study in 10 patients to determine whether velocity time integrals in the descending aorta and middle cerebral arteries and the peak velocity at the foramen ovale w ere acutely altered by changes in the fraction of inspired oxygen. Mea surements were performed after 10- to 15-minute intervals of breathing 14% to 19%, 21%, and 35% oxygen. Results: Antegrade descending aortic velocity time integrals did not change significantly when these patie nts breathed different amounts of oxygen; however, the retrograde velo city time integral in the descending aorta and the peak velocity of le ft-to-right shunt at the foramen ovale increased with increasing amoun ts of inspired oxygen. The ratio of antegrade to retrograde velocity t ime integrals in the descending aorta was greater with supplemental ni trogen than with supplemental oxygen. Middle cerebral arterial velocit y time integrals were not significantly greater with supplemental nitr ogen than with supplemental oxygen (p = 0.061). Conclusions: Systemic and interatrial Doppler velocities are acutely influenced by the fract ion of inspired oxygen in neonates with ductal-dependent systemic perf usion.