Fig. 5
Left: Right lateral view of the segmented fetal vasculature for quantitation of blood flow volumes. Color-coded contours indicate locations of corresponding flow measurements at right. Right: Blood flow waveforms (flow in mL/s vs cardiac time) at all measurement locations, separated by input (top) and output (bottom). Cardiac inputs from the DV, IVCd, IVCp, and SVC display typical biphasic nature with greater pulsatility nearer to the heart, whereas UV flow appears nearly constant. Note UV flow was measured downstream from the junction of the typical 2 UVs found in fetal sheep. Outputs from the MPA, DA, AAo, BT, and DAo display large systolic peaks and low diastolic flows. BT and PBF display retrograde diastolic flow, likely indicative of runoff to the placenta through the aortic isthmus and DA. UV: umbilical vein; DV: ductus venosus; IVCd: distal inferior vena cava; IVCp: proximal inferior vena cava; SVC: superior vena cava; FO: foramen ovale; AAo: ascending aorta; BT: brachiocephalic trunk; DA: ductus arteriosus; DAo: descending aorta; MPA: main pulmonary artery; PBF: combined pulmonary blood flow