Venous Thromboembolism Flashcards
Venous Thromboembolism (VTE)
Venous thrombus in deep veins = deep vein thrombosis
Who is at risk?
- immbolized
- diabetes
- birth control
- genetic defects
3 Risk factors for DVT?
Virchow's Triad: o Blood stasis • Bed rest or immobilization • Obesity • History of varicosities • Spinal cord injury • Age (greater than 65 years)
o Vessel wall injury • Trauma • Surgery • Pacing wires • Central venous catheters • Dialysis access catheters • Local vein damage • Repetitive motion injury
o Altered blood coagulation • Cancer • Pregnancy • Oral contraceptive use • Protein C deficiency • Protein S deficiency • Antiphospholipid antibody syndrome • Factor V Leiden defect • Prothrombin 20210A defect • Hyperhomocysteinemia • Elevated factors II, VIII, IX, XI • Antithrombin III deficiency • Polycythemia • Septicemia
What can DVT lead to?
pulmonary embolism
prevention of DVT?
- Increased mobility (post-surgical++) walk 10min every 1-2hrs
- Compression stockings
- Intermittent Pneumatic Compression Devices
- Prophylactic Anticoagulation Therapy
What are the signs and symptoms of DVT?
- Swelling – Measure calf and compare bilaterally. Mark area that has been measured.
- Pain
- Erythema – Outline area
- Cool or warm to touch
- Can be non-specific, hard to diagnose
What are the signs and symptoms of pleural embolism?
signs and symptoms are nonspecific
- Dyspnea (shortness of breath) • Tachypnea (rapid breathing) • Decreased spO2 • Chest pain of pleuritic nature (worsened by breathing) • Cough • Hemoptysis (coughing up blood)
What are the diagnostic texts for VTE?
• D-Dimer: Body’s natural reaction to clot development is fibrinolysis. D-dimer is produced by the action of plasmin on the fibrin polymer clot. will tell you theres a clot
• PTT, PT-INR, platelets why they have a clot and to monitor med effectiveness
o PTT: Monitors heparin clotting cascade
o PT-INR: Associated with warfarin and coumadin
• Ultrasound (U/S): Deep vein in legs
• CT: Chest to check for pulmonary embolism
What are the nursing non-pharmacological interventions for VTE?
o Monitor CWMS
o Measure limb (same spot every time for accuracy)
o Monitor skin integrity - VTE = increased risk of ulcer or skin breakdown
o Monitor for S&S (signs and symptoms) of clots
What are the nursing pharmacological interventions for VTE?
o Monitor and treat pain
o Administer anticoagulants, thrombolytic
♣ Anticoagulants do not break down a clot, anticoagulants stop the clot from getting bigger so the body can break it down
♣ Thrombolytics break down clots
o PE: Administer O2! Notify MRP is suspected, reposition for breathing, vital signs
Why would someone be on an anticoagulant?
- Immobility (post-surgical)
- Hx of DVT/pulmonary embolus
- Dysrhythmias (A-Fib) - heart not pumping effectively, blood pooling, causes clot
- Mechanical heart valve – Can cause injury and form clot on valve
- Post MI or stroke – MI and stroke usually due to clot, and they are at increased risk to develop more
** they do not break down clots **
Why use anticoagulants?
- Increases clotting time (seconds), to prevent thrombi from forming or growing larger
- Inhibit specific clotting factors in the coagulation cascade
- Therapeutic range narrow to prevent bleeding but also inhibit clotting
- They do not “break down a clot”
Heparin
Heparin • Given subcu or IV • IV = rapid onset o Weight based o Frequent monitoring of PTT
• SC heparin
o No or infrequent monitoring of PTT
o Usually given bid/tid
• Brief half-life (90 min)
• Risk of thrombocytopenia – Low platelets. Increased risk of bleeding.
• Protamine sulfate is antidote
• Benefit: Easier to control therapeutic range due to shorter half life
- Unfractionated heparin is administered subcutaneously to prevent development of DVT, or by intermittent or continuous IV infusion for 5 days to prevent the extension of a thrombus and the development of new thrombi. Oral anticoagulants, such as warfarin, are administered with heparin therapy. Medication dosage is regulated by monitoring the activated partial thromboplastin time (aPTT), the international normalized ratio (INR), and the platelet count.
Low Molecular Weight Heparin (LMWH)
- duration is 2-4 times longer than heparin
- Usually requires subcu injection daily
- Produce more stable response than heparin – works in less areas of the clotting cascade
- Decreased risk of thrombocytopenia
- Dosages based on patient weight
- Decreased follow up lab sites
- Patient/family member can be taught to self-administer
- Subcutaneous LMWHs that may include medications such as dalteparin and enoxaparin are effective treatments for some cases of DVT. These agents have longer half-lives than unfractionated heparin, so doses can be given in one or two subcutaneous injections each day. Doses are adjusted according to weight. LMWHs prevent the extension of a thrombus and development of new thrombi, and they are associated with fewer bleeding complications and lower risks of heparin-induced thrombocytopenia (HIT) than unfractionated heparin. Because there are several preparations, the dosing schedule must be based on the product used and the protocol at each institution. The cost of LMWH is higher than that of unfractionated heparin; however, LMWH may be used safely in pregnant women, and patients who take it may be more mobile and have an improved quality of life.
Warfarin
- Can be taken only PO
- Can take 3-5 days to reach therapeutic level
- Long half-life: 1-3 days
- Monitor PT-INR
- Antidote is vitamin K (orally or IV)
- Warfarin is a vitamin K antagonist that is indicated for extended anticoagulant therapy.
Routine coagulation monitoring is essential to ensure that a therapeutic response is obtained and maintained over time. Interactions with a range of other medi- cations can reduce or enhance the anticoagulant effects of warfarin, as can variable intake of foods containing vita- min K (see Chart 34-15). Warfarin has a narrow therapeutic window, and there is a slow onset of action. Treatment is initially supported with concomitant parenteral anticoagulation with heparin until the warfarin demonstrates anticoagulant effectiveness.
