Objective: To evaluate the changes in the distribution ratio of the umbilical venous blood flow to the ductus venosus(DV) in a near-term hircine fetus model with acute hypoxemia.
Methods: Twelve near-term fetal sheep(5 control group and 7 occlusion group) underwent umbilical cord occlusions(90-sec total cord occlusions 5 times at 30-min intervals)at 116~130 days gestation. The DV blood flow, the umbilical vein(UV) blood flow , the DV/UV ratio were performed 5 minutes before the first umbilical cord occlusions, 3 minutes after each occlusion.
Results: 1.In experimental group animals, the DV blood flow (70.25±15.47 ml/min~171.47±72.16 ml/min,P<0.05), the DV/UV ratio (0.24±0.03~0.96±0.3, P<0.05) increased with cord occlusions,and still significatly rose as compared with the control animals. The UV blood flow(298±67.45 ml/min~176.29±54.12 ml/min, P<0.05) descented with cord occlusions,and still significatly descented as compared with the control animals.2.There were negative correlation between the DV blood flow, the DV/UV ratio and pH(r=-0.681, r =-0.770, P<0.01).There were negative correlation between them and PaO2(r =-0.622,r =-0.797, P<0.01).There were significant relationship between them and PaCO2(r =0.418, r =0.658, P<0.01). There were significant relationship between the UV blood flow and pH, PaO2(r=0.324, r =0.580, P<0.01).There were negative correlation between the UV blood flow and PaCO2(r =-0.521,P<0.01).
Conclusions: Doppler ultrasonographic detection of the DV/UV ratio will be as a new prospective technique in screening of fetal acute hypoxemia.