Umbilical vein blood flow determination in the ovine fetus: Comparison of Doppler ultrasonographic and steady-state diffusion techniques

Byline: Henry L. Galan, Maciej Jozwik, Serena Rigano, Timothy R.H. Regnault, John C. Hobbins, Frederick C. Battaglia, Enrico Ferrazzi Keywords: Fetus; ovine; placenta; ultrasonography; umbilical blood flow; umbilical vein Abstract: 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. Study Design: 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 [+ or -] 8.6 mL * kg.sup.-1 fetus * min.sup.-1) was virtually identical to that determined with the steady-state diffusion technique (208.1 [+ or -] 7.3 mL * kg.sup.-1 fetus * min.sup.-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. (Am J Obstet Gynecol 1999;181:1149-53.) Author Affiliation: Denver, Colorado, Bialystok, Poland, and Milan, Italy From the Division of Perinatal Medicine, Departments of Obstetrics and Gynecology.sup.a and Pediatrics,.sup.b University of Colorado, the Department of Gynecology, Bialystok Medical University,.sup.c and the Department of Obstetrics and Gynecology, University of Milan..sup.d Article Note: (footnote) [star] Supported by National Institutes of Health Program Project Grants PO1 HD20761 and 1RO1 HD34837, March of Dimes Grant 6-F497-0174, and the American Association of Obstetricians and Gynecologists Foundation., [star][star] Reprint requests: Henry L. Galan, MD, Assistant Professor, Department of Obstetrics and Gynecology, University of Colorado Health Sciences Center, 4200 E 9th Ave, Campus Box B-198, Denver, CO 80262., a 0002-9378/99 $8.00 + 0 6/6/102316