Early postnatal changes in superior mesenteric artery blood flow velocity in healthy term infants.
OBJECTIVE
After birth, the newborn intestinal circulation undergoes physiological changes. The purpose of this work was to characterize the changes in mesenteric blood flow velocity occuring during the first three days of life in healthy term infants.


METHODS
30 healthy term newborns were studied repeatedly at the age of 2, 24 and 70 hours. Blood flow velocity in superior mesenteric artery (SMA) was measured by Doppler ultrasound, peak systolic velocity (PSV), end-diastolic velocity (EDV) and time-averaged mean velocity (TAV) were recorded at each time point. Resistance index (RI) and pulsatility index (PI) were calculated.


RESULTS
SMA EDV increased from 2 h [-5.2+/-6.8 cm/s (mean +/- SD)] to 24 h (12.9+/-3.8 cm/s, p<0.001) with further insignificant increase to 70 h (14.9+/-4.7 cm/s). At 2 h of age the mean EDV was negative in 23 of 30 cases (76.7%). PSV did not change between 2 h (58.0+/-21.8 cm/s) and 24 h (58.5+/-15.0 cm/s) but it increased to 70 h (79.6+/-17.7 cm/s). TAV showed a significant increase with time. RI decreased from 2 h (1.09+/-0.11) to 24 h (0.78+/-0.06, p<0.001) with further insignificant increase to 70 h (0.81+/-0.06).


CONCLUSIONS
The blood flow velocity in SMA increases during the early neonatal period in term infants. The most remarkable changes occur within the first 24 hours of life. At 2 h of age a reversed blood flow is present in majority of infants.
Matasova
Katarina
K
Clinic of Neonatology, Jessenius Faculty of Medicine, Martin, Slovak Republic. matasova@orangemail.sk
Zibolen
Mirko
M
Kolarovszka
Hana
H
Ciljak
Martin
M
Baska
Tibor
T
Murgas
Dalibor
D
Kolarovszki
Branislav
B
Dragula
Milan
M
D000222:Adaptation, Physiological; D000367:Age Factors; D000704:Analysis of Variance; D001783:Blood Flow Velocity / Q000502:physiology; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007231:Infant, Newborn; D007422:Intestines / Q000098:blood supply* / Q000000981:diagnostic imaging; D008297:Male; D017538:Mesenteric Artery, Superior / Q000000981:diagnostic imaging / Q000502:physiology*; D012016:Reference Values; D012039:Regional Blood Flow; D013152:Splanchnic Circulation / Q000502:physiology*; D018608:Ultrasonography, Doppler