We investigated regional hemodynamic maturation over the first two weeks of life in 17 VLBW infants (775 to 1245 g, 24 to 31 weeks gestation). Infants did not have symptomatic PDA but were given indomethacin (Indo) for IVH prophylaxis. Middle cerebral (C) and superior mesenteric artery (M) Doppler blood flow velocities (BFV) and cardiac function were recorded before Indo at 6, 30 and 54 hours of age and before and after feeding on days 7 and 14 of life (Fig., M ± SE). Cardiac output (CO) increased (ANOVA, p < 0.05) over the first 14 days of life as a result of combined increases in stroke volume and heart rate (p < 0.05). Contractility did not change. Mean and end-distolic CBFV increased by 71 and 374%, respectively (ANOVA, p < 0.05), from 6 to 54 hours of life with no further change from 3 to 14 days. In contrast, baseline MBFV did not change over the first 54 hours of life, but coincident with the initiation of feedings increased by 54% (ANOVA, p < 0.05) from 3 to 14 days. In response to feeding, mean MBFV increased 35% (p < 0.05) on day #7 and 17% (p = ns) on day #14. The post-prandial MBFV did not differ significantly on days 7 and 14. Maturational increases in cardiac function and regional BFVs were not related statistically to changes in ductus arteriosus patency, BP, SaO2, pH or PaCO2. We conclude that in VLBW infants, cerebral and mesenteric regional BFVs and CO increase significantly over the first 2 weeks of life. Region specific patterns of hemodynamic maturation are observed, with cerebral BFV increasing in the first 54 hours of life and preprandial mesenteric BFV increasing from 3 to 14 days, after enteral nutrition has been established. (Supported by Wyeth Pediatrics.)

figure 1

Figure 1