Although dopamine (DA) increases blood pressure (BP) and urine output in the hypotensive and/or oliguric neonate (Seri I, J Pediatr 126:333, 1995), the regional hemodynamic effects of the drug on organ blood flows have not been studied in the neonate. We compared the vascular responses to DA in the renal(RA), superior mesenteric (SMA), and middle cerebral (MCA) artery, and in the descending aorta (DAo) in 10 non-hypotensive, preterm neonates(GA=26.9±2.8, range=23-31 weeks; BW=1005±399, range 461-1810 g) during the first 2 days of life who presented with RDS and poor peripheral perfusion. Blood flow velocity profile was measured by Acuson XP color and a duplex Doppler unit with a 5.0/7.0 MHz Sector Probe at a close to zero angle. The pulsatility index (Pl = peak systolic velocity - lowest diastolic velocity divided by the mean velocity) was used to assess the drug-induced selective alterations in the renal (RBF), mesenteric (MBF), cerebral (CBF) and DAo(DAoBF) blood flows at a DA dose (2.5-7.5 μg/kg/min) which raised BP by 15 to 20% and improved peripheral perfusion. Table

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Conclusions: 1) In preterm infants with compensated shock, the DA dose which raises BP by 15-20% selectively increases RBF while MBF, CBF and DAoBF remain unchanged. This finding is the first demonstration of a selective renal vascular dopaminergic response in preterm neonates.2) In humans, maturation of the mesenteric vascular dopaminergic system may lag behind that of the kidney. 3) DA did not affect CBF .4) DA increased BP by raising both peripheral vascular resistance and cpardiac output, since DAoBF remained unchanged.