A CAUSE OF THE THROMBOCYTOPENIA AND LEUKOPENIA THAT OCCUR IN DOGS DURING DEEP HYPOTHERMIA

Abstract

Investigations have been made into the mechanisms of the thrombocytopenia and leukopenia that occur in hypothermic dogs. By tagging platelets with P32, the thrombocytopenia was shown to be caused by sequestration rather than destruction of platelets. This conclusion was supported by bone marrow studies which revealed no evidence of increased formation of platelets. By sampling the blood in various vessels through polyethylene catheters it was shown that the major site of platelet sequestration is in the portal circulation. Extirpation showed that the liver and spleen play a major role in the sequestration. However, since hepatectomized dogs still develop some thrombocytopenia, other areas must also be sites of sequestration. Changes in the leukocyte counts tended to parallel those of the platelets and were apparently due to similar mechanisms. However, they were not as consistent as those involving the platelets.