Blood flow distribution within the spleen distended by perfusion at high venous pressure.

Red cell washout from the isolated, Ringer-perfused cat spleen, dilated by perfusion at elevated venous pressure (25 cm H2O), was compared with that from the relaxed spleen perfused under normal venous pressure (6 to 8 cm H2O). Cell concentrations in the outflow were measured by a Celloscope counter and plotted on semi-logarithmic paper as a function of the volume of Ringer solution perfused. Washout kinetics from relaxed spleens yielded three exponential components, the V 1/2's being 3.1, 121, and 585 ml, respectively. In the case of dilated spleens, however, only two components were found. For spleens dilated, before washout, with blood in vivo the V 1/2 value were 50 and 415 ml; for normal spleens dilated in vitro, before washout, by Ringer perfusion at high venous pressure the V 1/2 values were 60 and 439 ml. The results indicate a greatly altered intrasplenic blood flow distribution in the presence of a high splenic venous pressure; the customary fast cmponent of flow is absent, and the blood appears to be directed entirely through the pulp. This must be the situation, presumably, in congestive splenomegaly arising from portal hypertension.