Umbilical vein blood flow determination in the ovine fetus: comparison of Doppler ultrasonographic and steady-state diffusion techniques.
OBJECTIVE
This study was undertaken to assess the accuracy of triplex ultrasonographic measurement of venous umbilical blood flow in comparison with the steady-state diffusion technique and to determine the impact of cotyledon weight and number on umbilical blood flow.


METHODS
Six late-gestation ewes with long-term catheter placement were studied for venous umbilical blood flow with the ethanol steady-state diffusion technique and with triplex-mode ultrasonography (color Doppler, pulsed-wave Doppler, and real-time ultrasonography). At necropsy the number and weight of the cotyledons serving each umbilical vein were recorded.


RESULTS
Umbilical blood flow determined by triplex-mode ultrasonography (207. 5 +/- 8.6 mL. kg(-1) fetus. min(-1)) was virtually identical to that determined with the steady-state diffusion technique (208.1 +/- 7.3 mL. kg(-1) fetus. min(-1); P =.9). When values were normalized for the weight or number of cotyledons serving each vein, there was no difference in umbilical blood flow between small and large umbilical veins in all the sheep.


CONCLUSIONS
Our study validates the accuracy of the triplex ultrasonographic method and provides justification for its use in future human investigations. In absolute terms umbilical blood flow frequently differs between the 2 veins. When expressed per number or mass of cotyledons, however, the umbilical blood flows are similar.
Galan
H L
HL
Division of Perinatal Medicine, Department of Obstetrics and Gynecology, University of Colorado, Denver 80262, USA.
Jozwik
M
M
Rigano
S
S
Regnault
T R
TR
Hobbins
J C
JC
Battaglia
F C
FC
Ferrazzi
E
E
D000818:Animals; D004058:Diffusion; D005260:Female; D006041:Goats / Q000502:physiology*; D009929:Organ Size; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000502:physiology*; D012039:Regional Blood Flow; D012044:Regression Analysis; D012680:Sensitivity and Specificity; D013997:Time Factors; D018608:Ultrasonography, Doppler; D014471:Umbilical Veins / Q000000981:diagnostic imaging* / Q000502:physiology*