Hepatic trapping of red cells in canine endotoxin shock: a variable phenomenon after splenectomy

We studied in 20 splenectomised dogs the incidence of early intravascular hepatic pooling after administration of E. coli endotoxin. Autologous red cells were labelled in vitro with 99mTc. Bloodpool imaging and haemodynamic measurements were performed simultaneously. Changes in hepatic red cell volume were estimated from alterations in hepatic activity. In 10 dogs, hepatic red cell activity increased considerably (156 to 359% of the basal value). In the remaining animals the hepatic activity did not change markedly or even decreased. The decline in arterial pressure and cardiac output seemed more pronounced in dogs with clear evidence of hepatic pooling. However no significant differences in absolute haemodynamic values could be demonstrated between dogs with and without pooling. It is concluded that an hepatic outflow block is not a constant feature of canine endotoxin shock. Absolute haemodynamic values do not depend on the presence of an outflow block. Thus the presence of hepatic pooling need not make the canine model inappropriate for studies on human sepsis.