Arterial blood pressure wave forms in radial and posterior tibial arteries in critically ill newborn infants.

The aim of this study was to document arterial blood pressure wave forms at two sites along the arterial tree of the neonate: in the radial and posterior tibial arteries. Using a high-fidelity catheter tip-transducer system, peripheral arterial blood pressure wave forms in 26 critically newborn infants were studied. In 14 infants the radial artery and in 12 infants the posterior tibial artery was cannulated. Radial artery blood pressure waves resembled those of proximal aortic rather than those of the radial artery in adults. Quantitative analysis of the waves was performed to reassure this finding. Blood pressure waves obtained from posterior tibial artery resembled those of femoral artery rather than those of posterior tibial artery waves in adults. We conclude that radial and posterior tibial artery wave forms in neonates appear to have a central appearance. This phenomenon might be explained by the close proximity of the radial and posterior tibial artery to the central aorta and femoral artery respectively, due to the small and short limbs of the neonate. The finding allows an "easy central pressure look" at both ends of the neonatal aorta.