This lesson focuses on the parenteral anticoagulants — unfractionated heparin and low molecular weight heparin — and the role they play in preventing and treating thromboembolic disease. Heparins are the workhorses of acute, hospital-based anticoagulation because they act quickly and, in the case of unfractionated heparin, can be reversed almost immediately when bleeding occurs or urgent surgery is needed. The registered nurse is responsible for safe administration, accurate monitoring, and rapid recognition of complications. Heparins are used to treat and prevent deep vein thrombosis and pulmonary embolism, to bridge patients onto oral anticoagulation, to manage acute coronary syndromes, and to maintain patency of vascular access in some settings. They work by enhancing the body's own clotting inhibitors rather than by dissolving existing clots, so the therapeutic goal is to stop a thrombus from growing while the body's fibrinolytic system gradually clears it. Two themes run through everything that follows. First, bleeding is the predictable, dose-related complication of every anticoagulant, so bleeding precautions and recognition of hemorrhage are constant nursing priorities. Second, heparin-induced thrombocytopenia (HIT) is a dangerous, immune-mediated reaction in...