Positioning of umbilical arterial catheters with ultrasound.

Fifty six infants were studied by ultrasound, 22 during the placement of the umbilical artery catheter. The descending aorta, bifurcation, common iliac arteries, and the intra-arterial catheter could be clearly seen. We recommend that the catheter tip be placed 5-10 mm above the aortic bifurcation thus avoiding the major branches of descending aorta.