Regional hemodynamic effects of dopamine in the sick preterm neonate

Objective: To study the effects of dopamine on renal, mesenteric, and cereb ral blood flow in sick preterm neonates. Study design: The pulsatility index was used to assess the dopamine-induced changes in renal, mesenteric, and cerebral blood flow by means of color Do ppler ultrasonography in 23 nonhypotensive preterm neonates (birth weight: 981 +/- 314 g; postnatal age: <2 days). Dopamine was given at a dose of 6.1 +/- 3.0 mu ug/kg per minute to combat oliguria, impaired peripheral perfus ion, or both. Blood flow velocity measurements were made before and during dopamine administration, with each patient serving as his or her own contro l subject. Results: Dopamine significantly increased blood pressure and urine output. Dopamine decreased the pulsatility index in the renal artery (2.98 +/- 1.18 vs 1.68 +/- 0.45; P < .05) while the pulsatility index in the superior mes enteric and medial cerebral artery was not affected. Thus renal blood flow increased while mesenteric and cerebral blood flow remained unchanged durin g dopamine treatment. The increase in renal blood flow was independent of t he blood pressure changes. Conclusions: These findings suggest a functionally mature renal, but not me senteric, vasodilatory dopaminergic response in the preterm neonate. The ob servations also indicate the lack of an effect of low- to medium-dose dopam ine on cerebral hemodynamics in the nonhypotensive preterm neonate.