Doppler assessment of human neonatal gut blood flow velocities: postnatal adaptation and response to feeds.

Duplex pulsed Doppler ultrasound was used to study changes in gut blood flow velocities during the first week of life in a group of 14 term babies. There was a significant increase in fasting peak systolic velocity in the superior mesenteric artery between days 1 and 2 with a further upward trend until day 5; no such changes were seen in the coeliac axis. Fasting velocities were 20% lower in breast-fed babies than bottle-fed babies. Following feeds, there was a significant increase in velocity in the superior mesenteric artery that was 35% greater in the bottle-fed than breast-fed babies. Changes in the coeliac axis were qualitatively similar but substantially smaller. The peak velocity in both vessels occurred 50 min after a feed. We conclude that Doppler ultrasound can be readily used to measure gut blood flow velocities in the human newborn. It provides a noninvasive technique for investigating adaptive postnatal changes in the splanchnic circulation, and, in particular, the response to feeds.