Detecting ductal shunting in premature infants by range-gated Doppler echocardiography

Range-gated pulsed Doppler echocardiography has been reported to be a useful noninvasive bedside technic for detecting ductal left-to-right shunting in premature infants. We studied 30 premature infants with a birth weight of less than 1,500 gm, using a 5 MHz system developed by Advanced Technology Laboratories. An umbilical artery catheter was used to obtain a contrast aortogram. Twenty-three infants had both a positive flush aortogram and a continuous turbulence documented by Doppler echocardiography. A clinically audible murmur was present in 17 of these patients. In six infants there was no Doppler evidence of PDA. In five of this last group there was also a negative flush aortogram. The excellent correlation found between the Doppler and aortographic studies suggests that this noninvasive technic is very sensitive for detecting ductal left-to-right shunting, even in the absence of an audible murmur.