Ultrasonic assessment of abdominal venous return. II. Volume blood flow in the inferior vena cava and portal vein.

Eighty-five patients subjected to routine heart catheterization, were examined with duplex scanning of the inferior vena cava and portal vein. Volume blood flow in the two veins was estimated and compared with Fick measured cardiac output and duplex measured flow in the lower thoracic aorta. Inferior vena caval and portal vein flow were found to comprise approximately 30 to 40 per cent and 20 per cent, respectively, of cardiac output, but with a large dispersion of individual percentages. A high correlation (r = 0.88) was found between the sum of inferior vena caval and portal vein flow and duplex measured flow in the lower thoracic aorta, the sum of flow in the two veins comprising approximately 90 per cent of lower thoracic aortic flow. It is concluded that duplex scanning seems to be a useful method in estimating volume blood flow in both the inferior vena cava and portal vein.