Venous Thromboembolism (M4A) Flashcards
VTE (venous thromboembolism) is made up of…
- DVT (deep vein thrombosis)
- PE (pulmonary embolism)
risk factors for DVT & PE
Virchow’s Triad:
- endothelial injury (creates site for clot formation)
- venous stasis
- altered coagulation
endothelial injury causes
- trauma
- Sx
- repetitive motion injury
- pacing wires
- local vein damage
- dialysis & central catheters
venous stasis causes
- bed rest or immobilization
- obesity
- Hx of varicosities
- spinal cord injury
- age (>65 yrs)
altered coagulation causes
- cancer
- pregnancy
- oral contraceptive use
- clotting disorders
- protein C & S deficiency
- polycythemia
- discontinuation of anticoagulant use
S&S of DVT
- swelling
- pain
- cool or warm to touch
- S&S can be nonspecific (asympt or have a “weird feeling”)
S&S of PE
- dyspnea (SOB)
- tachypnea (rapid breathing)
- dec SpO2
- chest pain of a pleuritic nature (worsened by breathing)
- cough
- hemoptysis (coughing up blood)
non-pharm nursing interventions
- monitor CWMS (color, warmth, movement, sensation)
- measure limb
- monitor skin integrity
- monitor for S&S of clots
- mobilization
- positioning
- compression stockings (if ordered)
- promote home, community based and transition of care
pharm nursing interventions
- monitor and treat pain
- anticoagulants & thrombolytics
- for PE, admin O2
drugs to treat DVT (medical management)
anticoagulants:
- LMW heparin (dalteparin & enoxaparin; 1st line of Tx)
- unfractionated heparin (IV)
- warfarin (PO)
endovascular management for DVT
- used when anticoagulant or thrombolytic therapy contraindicated, risk for PE, or venous drainage compromised
- thrombectomy (mechanical method of clot removal)
- vena cava filter (traps large emboli and prevents PE)
if pt receiving anticoagulant therapy, what lab values does nurse monitor?
- aPPTT
- prothrombin time (PT)
- INR
- ACT
- Hg & Hct
- platelet count
- fibrinogen level
Dx tests for VTE
- D-dimer
- PTT, PT-INR
- WBC differential
- CBC
- U/S (for deep veins in legs)
- CT scan (chest r/t PE)
D-dimer
= non-specific marker of fibrinolysis (for clotting)
- body’s natural rxn to clot development = fibrinolysis
- produced by the action of plasmin on fibrin polymer clot
antiplatelets - action
- suppress platelet aggregation
- prevent thrombosis in arteries
- ex. aspirin
aspirin (action, ADE & contraindications)
- action: suppresses platelet aggregation
- ADE: inc risk of bleeding (esp in GI)
- contraindications: not for children (Reye’s Syndrome), pregnant
anticoagulants - action
- inc clotting time to prevent thrombi from forming/growing larger
- inhibit specific clotting factors in coagulation cascade
- do not “breakdown” clot (only prevents clots)
anticoagulants - indications
- VTE prophalyxis
- Hx of DVT/PE
- dysrhythmias (A-fib)
- mechanical heart valve
- post-MI or stroke
examples of oral anticoagulants
- direct thrombin inhibitors (dabigatran)
- direct factor Xa inhibitors (rivaroxaban, apixaban)
- vit K antagonist (warfarin)
oral anticoagulant - important to know
- no routine monitoring of coagulation factors needed
- fixed dosage
- no antidote for OD
- avoid/limit IM injections (risk for hematoma)
if pt receiving oral anticoagulant therapy, what does nurse monitor?
- S&S of bleeding (hematuria, epistaxis, bloody stools, bruising)
- VS
- lab values
- hepatic/renal failure
- possible drug interactions
heparin (anticoagulant)
- given subQ or IV
- brief half-life
- antidote = protamine sulfate
- not usually given to prevent clots (pt has clot already)
admin of heparin inc risk for…
- thrombocytopenia (heparin-induced)
- hemorrhage
IV admin of heparin - important to know
- rapid onset
- weight based
- freq monitoring of PTT and signs of bleeding necessary
subQ admin of heparin - important to know
- infreq monitoring of PTT
- monitor for signs of bleeding
- usually given BID/TID
LMW heparin (anticoagulant)
- duration is 2-4x longer than heparin
- produces more stable response than heparin
- weight based dosage
- can be used at home
- monitor for S&S of bleeding
LMW heparin examples
- dalteparin
- enoxaparin
Vitamin K antagonist (anticoagulant)
- PO only
- can take 3-5 days to reach therapeutic level
- prevent thrombosis
- risk for hemorrage
- long half-life = 1-3 days
- monitor PT-INR
- antidote = Vitamin K
- many drug interactions
Vitamin K antagonist example
- warfarin
contrasts between warfarin and heparin
- warfarin PO; heparin injection
- warfarin inhibits synthesis of clotting factors; heparin inactivates thrombin & factor Xa
- warfarin effects begin slowly & persist for several days; heparin effects begin and fade rapidly
- monitor PT for warfarin; monitor aPTT for heparin
- vitamin K counteract warfarin; protamine counteract heparin
