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 E1 before surgical palliation or transplantation. At our institution, we adjust the fraction of inspired oxygen, with supplemental nitrogen if needed, to control pulmonary vascular 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 were acutely altered by changes in the fraction of inspired oxygen. Measurements 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 patients breathed different amounts of oxygen; however, the retrograde velocity time integral in the descending aorta and the peak velocity of left-to-right shunt at the foramen ovale increased with increasing amounts of inspired oxygen. The ratio of antegrade to retrograde velocity time integrals in the descending aorta was greater with supplemental nitrogen than with supplemental oxygen. Middle cerebral arterial velocity time integrals were not significantly greater with supplemental nitrogen than with supplemental oxygen (p = 0.061).

CONCLUSIONS

Systemic and interatrial Doppler velocities are acutely influenced by the fraction of inspired oxygen in neonates with ductal-dependent systemic perfusion.