title: Doppler echocardiographic assessment of fetal descending aortic and umbilical blood flows. Validation studies in fetal lambs.
abstract: BACKGROUND
  Doppler ultrasound has been used to assess abdominal aortic and umbilical blood flows in the human fetus, but the accuracy of this approach has not been demonstrated in an animal model.
  
  
  RESULTS
  We compared abdominal aortic and umbilical blood flows determined by Doppler echocardiography in 12 fetal lambs with invasive flow measurements using radionuclide-labeled microspheres and electromagnetic flow transducers. We varied fetal blood flow from 100 to 950 ml/min in the abdominal aorta and from 130 to 610 ml/min in the umbilical vein. Invasive and Doppler echocardiographic flow measurements correlated well at both sites (y = 68 + 1.02x, r = 0.94, and y = 33 + 1.1x, r = 0.91, respectively). A slight overestimation of flow using the Doppler method may require a correction factor to assess actual flow. The degree of overestimation was not systematically related to measurements taken in smaller vessels or at larger angles of incidence.
  
  
  CONCLUSIONS
  The present study demonstrates that determination of abdominal aortic and umbilical venous flows by echocardiography and pulsed Doppler ultrasound is feasible. Doppler measurements appear to be suited to serial comparison of actual flow.
authors.affiliation: Cardiovascular Research Institute, University of California, San Francisco 94143.
authors.forename: K G
authors.initials: KG
authors.lastname: Schmidt
authors.forename: M
authors.initials: M
authors.lastname: Di Tommaso
authors.forename: N H
authors.initials: NH
authors.lastname: Silverman
authors.forename: A M
authors.initials: AM
authors.lastname: Rudolph
mesh_terms: D000818:Animals; D001013:Aorta, Thoracic / Q000033:anatomy & histology / Q000502:physiology*; D015150:Echocardiography, Doppler; D005069:Evaluation Studies as Topic; D005333:Fetus / Q000502:physiology*; D012039:Regional Blood Flow; D012756:Sheep / Q000196:embryology; D014471:Umbilical Veins / Q000033:anatomy & histology / Q000502:physiology*