Haematology and the Extracorporeal Circulation.

The experience gained in the investigation of 100 cases of cardiac surgery treated by use of extracorporeal circulation has shown that certain simple laboratory tests suffice to detect induced defects in the blood and to guide therapy. These tests have been devised to detect the level of circulating heparin during perfusion; the presence of residual heparin following perfusion; the existence of a qualitative or quantitative fibrinogen deficiency; excessive fibrinolysis. Any of the latter three abnormalities alone or together have caused excessive immediate post-operative blood loss. Specific therapy has not been found to be necessary unless severe bleeding occurs.