The clinician is more and more frequently confronted with the decision as to whether or not to give a patient anticoagulants beyond his hospital stay. Indications for longterm therapy are quite definite in some conditions and less so in others. Once the decision is made to continue such therapy over a period of months or years the burden on both patient and physician may be materially eased if certain principles are understood and practices followed. Since long-term therapy with heparin is for the most part impractical, it is the prothrombin depressants with which the clinician is chiefly concerned in prolonged anticoagulant administration. It is the purpose of this paper to discuss briefly certain principles of such therapy and to emphasize the practical aspects of their application.
Methods of Control
Despite recent advances in our knowledge of the mechanism by which blood clots, our assays for clotting factors are still not