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 (EDVSMA) at 24 h and PSVTC 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 EDVSMA. Mean PIAMS 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.

Very early postnatal changes in splanchnic circulation in term infants.

BACKGROUND: Reversed blood flow has been reported in the superior mesenteric artery (SMA) in 92% of healthy term newborns at 2 h of age. By 24 h after birth the end-diastolic velocity became positive in all of the infants. OBJECTIVE: To characterize hemodynamic changes in the coeliac artery and superior mesenteric artery in healthy term newborns during the first 6 h after birth and to specify the time interval when the negative values of end-diastolic velocity in the superior mesenteric artery become positive. MATERIALS AND METHODS: Our study included 30 healthy term newborns. The blood flow velocity was assessed by Doppler ultrasonography at 2 h, 4 h and 6 h after birth. RESULTS: The end-diastolic velocity in the superior mesenteric artery changed from negative values at the age of 2 h (-0.9 cm/s, range -13.2 to 0.0) to positive (7.08 cm/s, range 6.3 to 13.5, P < 0.001) at 6 h after birth. In the coeliac artery, the end-diastolic velocity increased during this period, but negative values were not observed (11.8 cm/s, range 9.3 to 13.9 at 2 h and 18.03 cm/s, range 14.2 to 27.6 at 6 h). CONCLUSION: Important changes occur in splanchnic circulation during the first 6 h after birth. The rise in end-diastolic velocity in the superior mesenteric artery from negative to positive values in 83% of healthy term newborns is the most important change.