Page 170 - Cardiac Nursing

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146 PA R T II / Physiologic and Pathologic Responses

Table 6-7 ■ DRUGS USED TO PROMOTE ANTICOAGULATION
Drug Category Mechanism Dose
Heparin, Binds to and activates antithrombin III and reduces Load: 5,000 u or 75 u/kg followed by initial infusion 18 units/kg/min;
unfractionated (UFH) the formation of thrombin and fibrin adjust according weight based protocol using aPTT (goal is usually
1.5 to 2.5 times the normal aPTT value 70 seconds)
Heparin, Similar to heparin but reduced ability to catalyze 1.5 mg/kg subcutaneously (SC) if dosed daily or 1.0 mg/kg if dosed
low-molecular-weight the inhibition of thrombin with retained ability to q12hr (treatment doses)
(LMWH), Enoxaparin inhibit activity of factor Xa Prophylaxis dose range 20 to 60 mg q12hr depending on indication
Heparin, Same as enoxaparin 100 units/kg q12hr or 200 u/kg SC daily (treatment dose)
low-molecular weight, 2500 units 1 to 2 h preoperation and daily (prophylaxis)
Dalteparin
Antithrombin-dependent Indirect inhibition of factor Xa and thrombin 750 units SC twice daily (prophylaxis)
anticoagulant, activity For HIT: 2250 units followed by 400 u/h 4 h then 300 u/h 4 h
Danaparoid then 150 to 200 u/h*
Factor Xa inhibitor, Inhibits Factor Xa but not thrombin 2.5 mg SC daily
Fondaparinux
Oral anticoagulants, Antagonist of vitamin K Dosed according to PT/INR (goal is related to reason for
Warfarin anticoagulation; usual INR goal is 2.0 to 3.0)
Plasminogen activator, Induce a conformational change in plasminogen by 250,000 IU IV load followed by infusion 100,000 IU/h for 24 h
Streptokinase proteolytically cleaving plasminogen to plasmin,
enhancing fibrinolysis; no fibrin specificity
Plasminogen activator, Same as streptokinase 2,000 IU IV load followed by infusion 2000 IU/h for 24 to 48 h
Urokinase
Plasminogen activator, Same as streptokinase but has relative fibrin 100 mg over 2 h
t-PA specificity
Thrombin inhibitors, Directly inhibits thrombin formation enhancing 1 to 2 mcg/kg/min infusion not to exceed 10 mcg/kg/min;
Argatroban fibrinolysis adjust for hepatobiliary dysfunction*
Thrombin inhibitors, Same as argatroban 0.4 mg/kg loading dose followed by 0.15 mg/kg/h infusion
Lepirudin For HIT: 0.2 to 0.4 mg/kg bolus (only in case of life threatening
thrombosis) followed by infusion at 0.1 mg/kg/h; reduce for renal
dysfunction*
Thrombin inhibitors, Same as argatroban 1 mg/kg bolus; 2.5 mg/kg/h 4 h then 0.2 mg/kg/h to 20 h
Bivalirudin
*Warkentin, T. (2007). Heparin-induced thrombocytopenia. Hematology/Oncology Clinics of North America, 21(4), 589–607.
Modified from Francis, C., & Kaplan, K. (2006). Willaims’s hematology (7th ed.). New York: McGraw-Hill Medical Publishing Division.

return. Other measures to promote venous return are pneumatic redness, swelling, asymmetry, and tenderness, are critical. If any
compression stockings, graduated compression stockings, elevat- signs and symptoms are observed, objective diagnostic testing
ing the foot of the bed 6 to 8 inches, and not raising the knee should be pursued. Bleeding is the most common complication of
gatch to avoid excessive popliteal pressure. A thorough history of anticoagulant and fibrinolytic therapy. The patient must be ob-
the patient’s risk factors along with the vigilant physical assess- served for subtle signs of bleeding. Careful monitoring of all
ment of extremities for any evidence of inflammation, such as puncture sites is mandatory, especially femoral interventional

Table 6-8 ■ LEVELS OF THROMBOEMBOLISM RISK IN SURGICAL PATIENTS WITHOUT PROPHALAXIS
Risk Category Successful Prevention Strategies
Low Risk
Minor surgery in patients 40 years old with no additional risks No specific prophylaxis except early and “aggressive” ambulation
Moderate Risk
Minor surgery in patients with additional risk factors Low-dose unfractionated heparin (LDUH) q12h
Surgery in patients aged 40–60 years with no additional risk factors Low-molecular-weight heparin (LMWH) 3,400 units daily; graduated
compression stockings (GCS) or intermittent pneumatic compression
High Risk
Surgery. 60 years old or age 40–60 years with additional risk LDUH q 8 hours; LMWH 3,400 units daily or intermittent pneumatic
factors (prior VTE, cancer, or molecular hypercoagulability) compression
Highest Risk
Surgery in patients with multiple risk factors (prior VTE, cancer, LMWH 3,400 units daily, fondaparinux, oral
age 40 years)
Hip or knee arthroplasty, major trauma, spinal cord injury Vitamin K antagonists (INR 2–3); or intermittent pneumatic
compression/GCS
LDUH/LMWH

Modified from Geerts, W., et al. (2004). Prevention of venous thromboembolism: The Seventh ACCP Conference on Antithrombotic and Thrombolytic Therapy.
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Chest, 126(3, Suppl.), 338S–400S.