Deep Vein Thrombosis Flashcards
what is DVT?
formation of a clot in deep vein.
It is a type of VTE (Venous thromboembolism). Other type of VTE is Pulmonary embolism
what veins are most susceptible to DVT formation ?
veins located in the pelvis, lower leg (calf) and thighs
This includes superficial femoral, popliteal, posterior tibial & peroneal
DVTs tend to occur in the lower extremities (legs), but can occur in the upper extremities as well. However, DVTs in the lower extremities tend to have a higher chance of ……………
breaking off and turning into a PE (pulmonary embolism)
what makes a DVT so dangerous?
the potential for it to lead to pulmonary embolism
What factors play a role in the development of a DVT? To answer that question, we must review __________ __________
Virchow’s Triad.
Virchow’s Triad gives us three main factors that can lead to blood clot formation within a vein. Remember there are THREE factors (hence why it’s called a Triad).
Anyone can develop a deep vein thrombosis, especially if these risk factors are present.
Mnemonic for Virchow’s Triad
SHE
Stasis of Venous Circulation:
Hypercoagulability
Endothelial damage to the vein:
What would cause the blood in the venous system to become stagnant and not really move ?
the blood has to flow back to the heart via the veins, and it does this with the assistance of healthy vein valves and the muscles within the extremity. If the vein’s valves are damaged or the muscles aren’t working (or being used) blood isn’t going to flow back very well and a blood clot can develop.
when blood hangs out together for a while it starts to _____ together
stick cuz it has platelets in it
Blood cannot just hang out and become static within a vessel. If it does this the blood will start to clump up (due to the present of platelets) and form a clot.
What are some conditions that cause stasis of blood flow?
Immobilized
Varicose Veins (damaged valves allow blood backflow)
Surgery (hip or knee)
Traveling for long hours without moving extremities
Obstruction: late pregnancy, obesity
Heart failure (left ventricular dysfunction)
Atrial fibrillation
What are some conditions that cause an increased risk of forming a clot within the vessel?
Cancer Severe illness (sepsis) Dehydration Usage of Estrogen (birth control) Heparin Induced Thrombocytopenia (HIT) Postpartum Period
What are some conditions that cause damage the endothelial lining?
This endothelial is a layer of cells that lines the inside of the vein. Damage to this layer can be from a direct or indirect cause, but regardless it stimulates platelets and the coagulation process. So think of anything that damages the lining inside the vessel.
IV drug usage ( also venipuncture…drawing blood from a vein)
Indwelling devices (central line catheter, IV line, or heart valves etc.)
Medications that are damaging to the vein
Trauma or injury to the vessel (surgery)
Regardless of the factor(s) contributing to the blood clot, as identified by ________ Triad, platelets are involved.
The platelets start to collect at the edges of the vessel, usually within the _______- of the vein’s valve. Platelets normally help create a seal to stop the bleeding. So, when they start to work within the vessel it _________ other chemicals called clotting factors.
Clotting factors cause __________ to be created. Fibrin causes the big problem in terms of a clot developing because fibrin is like strands of mesh. This causes WBCs, RBCs, and platelets to ___________-within the vein.
This forms a clot and it continues to grow, which can eventually break off and enter venous circulation.
Virchow’s; cusps; recruits; fibrin; stick together
S/S of DVT
Redness
Swelling
Very warm
Pain
Homan’s Sign: NOT reliable for detecting a DVT because of false positives… but know for exams how to elicit a response:
Extend the patient’s leg and manually dorsiflex the patient’s foot (bend it up towards the shin). If it causes the patient pain, it considered a Positive Homan’s Sign.
How to test for Homan’s sign
Homan’s Sign: NOT reliable for detecting a DVT because of false positives… but know for exams how to elicit a response:
Extend the patient’s leg and manually dorsiflex the patient’s foot (bend it up towards the shin). If it causes the patient pain, it considered a Positive Homan’s Sign.
Nursing interventions for DVT: it can be diagnosed with
ultrasound
What is a D-Dimer test ?
What is it assessing for ? What is it used to diagnose?
Does it tell us where the clot is located ?
Does a positive result mean the patient has a clot ?
D-dimer (also called fibrin degradation fragment)
This is a blood test that assesses for fibrin degradation fragment (d-dimer), it’s a fibrin degradation product.
Used to diagnose blood clots or Disseminated Intravascular Coagulation (DIC).
This is a protein fragment that hangs out in the blood when a clot breaks down. So this means a clot has formed and has started to break down.
A D-dimer doesn’t tell us where the clot is located, so it will need to be further investigated by the MD. Also, a positive result doesn’t necessarily mean the patient has a clot because some disease processes can cause a false positive.
Example: Liver disease, MI, surgery (heart), cancer, pregnancy
Normal D-Dimer
FEU
&
DDU
D-dimer can be reported in fibrinogen equivalent units (FEU) or d-dimer units (DDU).
Normal level: <500 ng/mL FEU
<250 ng/mL DDU
as a nurse, we play a huge role in preventing ________________ in our patients
deep vein thrombosis
Pneumatic Compression Devices such as SCD’s
What should we tell patient about them? When should we wear them? Infection prevention?
Should we put them on an extremity that has an active DVT?
sequential compression devices - need to be fitted properly. Need to be plugged in.
Ask patient whether they are actually inflating and deflating
Make sure patients wear them all times when they are sitting or in bed. Can take them off when up walking.
Make sure to change regularly. Can get really sweaty and smelly underneath in order to prevent infection
Don’t put SCD on extremity with a DVT because it could dislodge the clot
DVT Nrsng Interventions for Prevention
Assess for the signs and symptoms and risk factors above and take precautions with prevention.
Application and regular usage of pneumatic compression devices like (SCDs) Sequential Compression Device per MD order. These devices wrap around the legs and inflate and deflate to help move blood flow (similar to walking).
Patient needs to be ambulating daily and out of the bed with all meals, if possible.
Teach patient to perform exercises by flexing and extending feet and legs every hour while awake.
Compression stockings per MD order: provides a specific amount of compression to help decrease risk of blood clot development.
Prophylactic medications: after surgery (post-op), especially joint replacement surgery like the hip… Example: Enoxaparin (subq injection)
Enoxaparin (Lovenox)
anticoagulent
what is our role for a patient who actually has a DVT ?
DEEP CLOT - what is the D?
Don’t rub or massage affected extremity (can dislodge clot)
DEEP CLOT - what are the two E’s?
Elevate the affected extremity above heart level (promotes blood return and decreases swelling)
Ensure bed rest - we don’t want the clot to become dislodged from moving around
DEEP CLOT - what is the P?
Pharmacological Measures Include:
Anticoagulants: do NOT break up the clot but helps prevent new ones from developing and from getting bigger.
Heparin: Indirect thrombin inhibitor
Enhances the activity of antithrombin III, which will inhibit thrombin and the conversion of fibrinogen to fibrin. (acts fast) given IV or subq…weight-based
Monitor aPTT (activated partial thromboplastin time): 1.5 to 2.5 times normal ranges
>80 seconds risk for bleeding….dose decreased
<60 seconds NOT therapeutic…risk for clots and may need dosage increased
Used in combination with Warfarin until INR is therapeutic and then Heparin is discontinued.
Antidote: protamine sulfate
Warfarin: Vitamin K antagonist
Since it’s a Vitamin K antagonist, it will work to inhibit clotting factors from using Vitamin K.
Slow onset….takes 3-5 day for patient to become therapeutic
Taken orally
Monitor PT/INR…therapeutic INR is 2-3 (less than 2…not therapeutic) and greater than 3 at risk for bleeding)
Antidote: vitamin K
Thrombolytics: catheter-directed thrombolysis with tPA…clot busting agent delivered directly to the clot (watch out for bleeding).
Filter: IVC filter (small metal device
placed in the inferior vena cava to prevent blood clots from enter the heart and lungs)
Many times this is placed for patient who can’t take anticoagulants.
do anticoagulants break up ana existing clot?
no - they prevent existing clots from getting bigger and any new clots from forming
heparin can be used in combination with warfarin until the ________ is therapeutic
INR
DEEP CLOT - what does the C stand for ?
Compresses (warm/moist) helps pain and circulation
DEEP CLOT - what does the L stand for ?
Leg circumference measurement (calf)…measure about 10 cm or 4 inches below tibial tuberosity…watch out for a 3 cm circumference or more measurement when compared to the non-affected calf.
with thrombolytics, there is a high risk of __________
bleeding
DEEP CLOT - what is the O?
Observe for S/S of a Pulmonary Embolism
sudden shortness of breath, decreased oxygen saturation, fast heart rate, chest pain, very anxious, sweating, coughing
DEEP CLOT - what is the T?
Tight compression stockings (thigh or knee high compression) per MD order…helps promote blood flow and decreases swelling (change regularly and show patient how to apply)
Fitted and applied properly as prescribed
Compression stockings may prevent PTS (post-thrombotic syndrome), which happens sometimes after the development of a DVT. This is because vein valves and walls became damaged due to the clot…blood doesn’t flow in the right directions (back to the heart).
The only time a patient should not wear the SCDs is when they’re ambulating. TRUE OR FALSE
TruE
_________ thrombi develop at sites where blood flow is slow
Venous
______________ of blood initiates the coagulation cascade; resulting in the production of fibrin, which enmeshes red blood cells and platelets to form the thrombus
Stagnation
The typical venous thrombus has a long tail that can break off to produce an __________
What is the danger with this ?
embolus; they travel within the vascular system and become lodged at faraway places, frequently the pulmonary arteries.
Injury from a venous thrombus occurs secondary to embolization at a site distant from the original thrombus
