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 72 h 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 72 h.
Results: Significant end-diastolic velocity (end-diastolic velocity (EDV) _SMA ) rise up to 24 h was documented in all patients (late preterm: -9.32 ± 9.48 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 2 h in 75% late preterm neonates. Preterm infants showed significantly higher mean peak systolic velocities (peak systolic velocity (PSV) _SMA ), end-diastolic velocities (EDV _SMA ) at 24 h and PSV _TC at 72 h than term infants (p < .05). The resistance and pulsatility indices (PI) decreased within 24 h in both groups and inversely reflected the postnatal changes in EDV _SMA . Mean PI _AMS at 2 h 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.