Y. Agata et al., REGIONAL BLOOD-FLOW DISTRIBUTION AND LEFT-VENTRICULAR OUTPUT DURING EARLY NEONATAL LIFE - A QUANTITATIVE ULTRASONOGRAPHIC ASSESSMENT, Pediatric research, 36(6), 1994, pp. 805-810
To examine the serial changes of left ventricular output and regional
blood flow distribution during the early neonatal period, we measured
blood flow volume in the ascending aorta, middle cerebral artery, celi
ac artery, superior mesenteric artery, and renal artery in 23 normal t
erm infants at 1, 4-8, 24, and 96 h after birth. The blood flow volume
in each vessel was measured by the pulsed Doppler technique. In the m
iddle cerebral artery, celiac artery, and superior mesenteric artery,
the blood flow volume at 1 and 4-8 h of age was significantly lower th
an after 24 h of age. In contrast, renal artery blood flow volume did
not change significantly throughout the study period. The reduced orga
n blood flow volume soon after birth was related to a low diastolic bl
ood flow in the major vessels, and the percent diastolic integral of b
lood flow velocity in each vessel showed an inverse linear correlation
with the diameter of the ductus arteriosus. The left ventricular outp
ut 1 h after birth was 365 +/- 69 mL/kg/min, which was significantly h
igher than after 4-8 h of age. Left ventricular output gradually decli
ned to 301 +/- 63 mL/kg/min at 4-8 h of age (p < 0.05 versus 96 h), 27
2 +/- 48 mL/kg/min at 24 h, and 258 +/- 54 mL/kg/min at 96 h. There wa
s a significant positive correlation between left ventricular output a
nd the ductus arteriosus diameter. We concluded that 1) there were sig
nificant changes in organ blood flow during the period of ductal closu
re, 2) the high left ventricular output and reduced regional blood flo
w at 1 and 4-8 h after birth resulted from diastolic left-to-right shu
nting through the ductus arteriosus, and 3) left ventricular output an
d regional organ blood flow were not directly related to each other. O
ur findings on the changes in regional organ blood flow and left ventr
icular output may provide a useful basis for interpreting abnormal hem
odynamics in the early postnatal period.