Question | Answer |
What are triggers for clot formation? | Intravascular - ASHD = arteriosclerotic heart disease
Extravascular - trauma |
What is hemostasis? | The body's ability to clot
Have to have platelets to clot
Have to be able to make fibrin
If you cut an artery, vessels will constrict to cut-off blood loss |
What is Virchow's triad? | Venous stasis - bad circulation
Hypercoaguability - thick blood (diabetes)
Endothelial damage - hurt the vessel |
What are the factors linked to increased risk of thromboembolic events? | Thrombus - clot; Embolic = move
Decreased circulation
Decreased mobility
Disease or disability
Obesity
Obstruction of venous flow; fat build-up
Medications |
What is an anticoagulant? | Prevent clots in the first place
Heparin is the drug of choice
Rapid acting
Does not dissolve a clot, but prevents one from forming |
What is an antiplatelet? | Make platelets less sticky (i.e. ASA) |
What are thrombolytics? | Chomp the clots and break them down (i.e. pac man)
Only drugs that break down existing clots
i.e. tPA, streptokinase, urokinase |
Indications for heparin use | DVT
PE
MI
Pregnancy
CVA |
What are mechanisms of action of heparin? | Can only be given parenterally; SubQ or IV
Not absorbed in GI tract
Very acid solution
Large molecule
Rapid acting
Dosed in units |
What are some injectable anticoagulants? | Heparin
Low molecular weight heparin (LMWH) |
What are some oral anticoagulants? | Coumadin and pradaxa |
What is an antiplatelet drug? | ASA |
What are some thrombolytics? | tPA, Streptokinase, Urokinase |
What are the pharmokinetics of heparin? | Rapid acting
Metabolized by liver
Eliminated via kidney
Short half-life
Highly protein bound - will sit in fat and sometimes cross BBB |
What are the ADRs of heparin? | Hemorrhage - has systemic-wide impact (gums can bleed, blood in urine, blood at IV site)
Osteoporosis
HIT - Heparin Induced Thrombocytopenia - lose all platelets = allergic reaction |
What are nursing indications with heparin? | Need to look for signs of bleeding
Respiratory rate up, BP down, HR up, extremities feel cool or look mottled
Changes in LOC, agitation
IV - do not mix with other meds
SubQ - rotate sites, don't massage |
What are nursing implications of heparin? | Monitor aPTT should be 60 to 80 seconds (1.5 to 2X normal of 40 seconds)
Monitor for bleeding
Protamine sulfate is antidote |
What are characteristics of LMWH? | 100% bioavailability SubQ
Fragments of unfractionated heparin |
What are the mechanisms of action of LMWH? | Half-life 6X longer than heparin
Minimal protein binding
Renal clearance |
What are some nursing implications with LMWH? | Obtain baseline aPTT, PT, CBC, creatnine
Administered SubQ every 12-24 hours
Antidote = protamine sulfate |
What are some characteristics of Warfarin? | Coumadin
Oral anticoagulant
Inhibits liver synthesis of vitamin K
Absorbed rapidly in upper GI tract |
What are the actions of Warfarin? | Long half-life (42 hours)
Highly protein bound
Works on what's coming - does not work on what's currently circulating
Prevents thrombosis formation - doesn't treat anything |
What are ADRs of Warfarin? | Multiple drug interactions
Hemorrage - major - bleeding in brain possible
Cannot use on pregnant women - crosses placental barrier |
What are nursing implications for warfarin? | Monitor for bleeding - PT level is 1.2 to 1.5X control OR INR level should be 2-3
Patient teaching so they can go home
Antagonist vitamin K - higher vitamin K will decrease effectiveness of coumadin |
What is vitamin K's impact when using coumadin? | Decreases effectiveness of coumadin.
High vitamin K = broccoli, cucumber, brussel sprouts
Mod vitamin K = green beans, raw cabbage
Low vitamin K = apples |
Pradaxa/Xarelto advantage? | Need regular blood work on coumadin, not on these, though
Stroke could be your first sign of issues, though |
What are some antiplatelet drugs? | ASA |
Properties of ASA | Inhibits prostaglandin synthesis
Dose = 81 to 325 mg/day
Adverse effects - upset stomach, will interact with other anticoagulants and increase blood thinning effects |
Properties of thrombolytic drugs | tPA, streptokinase, urokinase
Get rid of existing clots
Causes low BP, bleeding, cardiac arrythmias
Used for MI, DVT, PE (massive) |