The early postnatal blood flow characteristics in the superior mesenteric and coeliac arteries in late preterm neonates

Objectives: The objective of this study is to evaluate intestinal blood flow changes within the first 72h in the late preterm infants in comparison with the healthy term neonates.Methods: In this prospective study, we analyzed Doppler flow velocity waveforms of superior mesenteric artery (SMA) and coeliac trunc (TC) in 20 late preterm and 20 term infants at the age of 2, 24, and 72h.Results: Significant end-diastolic velocity (end-diastolic velocity (EDV)(SMA)) rise up to 24h was documented in all patients (late preterm: -9.329.48 to 17.01 +/- 6.94; p<.05; term: -8 +/- 5.74 to 12.39 +/- 3.33; p<.001), associated with a conversion from negative values to positive ones. Reversed blood flow was documented in SMA at 2h in 75% late preterm neonates. Preterm infants showed significantly higher mean peak systolic velocities (peak systolic velocity (PSV)(SMA)), end-diastolic velocities (EDVSMA) at 24h and PSVTC at 72h than term infants (p<.05). The resistance and pulsatility indices (PI) decreased within 24h in both groups and inversely reflected the postnatal changes in EDVSMA. Mean PIAMS at 2h was significantly higher in term neonates.Conclusion: Late preterm neonates show similar progressive postnatal increase in blood flow velocities accompanied with a decrease in vascular resistance in SMA and TC then term neonates.