Week 7: Chp 31: Deep Vein Thrombosis (DVT) Flashcards
What is a Deep Vein Thrombosis (DVT)?
a blood clot in a large vein, usually in the leg or pelvis
Pulmonary embolism
where a DVT detaches from the site of formation and becomes mobile in the bloodstream; if the circulating clot moves through the heart to the lungs, it can block an artery supplying blood to the lungs
-can cause death, particularly when one or more of the vessels that supply the lungs with blood is completely obstructed
Venous thromboembolism (VTE)
disease process that includes DVT and/ or pulmonary embolism (PE)
- a person can develop another VTE within 5 years of first one if they survive the first occurrence
- hospitalization is a risk factor (injury and surgery are causes of vascular injury and the prolonged bedrest)
What are the risk factors for Venous thromboembolism (VTE)
hospitalization; injury and surgery are causes of vascular injury and the prolonged bedrest associated with hospitalization can cause venous stasis leading to clot formation
-half of new VTE cases occur during a hospital stay or within 90 days of an inpatient admission or surgical procedure, and are not diagnosed until after discharge`
Risk Factors of Deep Vein Thrombosis
-increasing patient age
-active cancer with or without concurrent chemotherapy
-varicose veins
-prior venous thrombosis
-pregnancy
postpartum period
-oral contraceptive and hormone therapy
-surgery
-trauma
-hospital or nursing home confinement resulting in immobility
-procedures such as central vein catheterization or transvenous pacemaker insertion
Virchow’s Triad
describes the factors implicated in the formation of a venous thrombosis
-decreased flow rate of the blood or stasis of blood flow, damage to the blood vessel wall; endothelial injury, and an increased tendency of the blood to clot (hypercoagulability)
Where is DVT most commonly located
DVT, more common in the veins of the lower extremity, develop in the deep veins of the calf muscles, or, less frequently, in the proximal deep veins of the lower extremity or upper arm
-the deep veins that lie near the center of the leg are surrounded by powerful muscles that contract and force deoxygenated blood back to the lungs and heart; one-way valves prevent the backflow of blood between the contractions; blood is squeezed up the leg against gravity, and the valves prevent it from flowing back to the feet; when the circulation of the blood slows down because of illness, injury, or inactivity, blood can accumulate or “pool”, which provides an ideal setting for clot formation
Clinical Manifestations
may or may not have symptoms
- the clots can cause partial or complete blockage of circulation in the vein, which can lead to pain, swelling, tenderness, discoloration, or redness and warmth in the affected area
- clinical manifestations vary depending on the size, location, degree of vessel occlusion, and adequacy of collateral circulation
- the presence of Homans’ sign, calf pain elicited on dorsiflexion of the foot, may indicate presence of DVT
Medical Management: Diagnosis
include a combination of pre-test probability (PTP) testing, D-dimer testing, and compression ultrasonography (CUS)
- evaluation of a patient with a suspected DVT begins with an assessment of a set of clinical prediction rules, pre-risk probability to DVT
- the Wells score is a PTP scoring system that categorizes patients as high, moderate, or low probability; this is based on clinical features commonly associated with DVT and an identification of an alternative diagnosis
Most accurate, safe, and effective diagnosis tools for DVT
combination of pre-test probability (PTP) testing, D-dimer testing, and compression ultrasonography (CUS)
D-dimer Testing
the next step if a patient has low or moderate probability in the DVT PTP scoring system
- the test is a global marker of coagulation activation by measuring fibrin degradation products produced from fibrinolysis (clot breakdown)
- a negative D-dimer test can exclude DVT without an ultrasound
- an elevated D-dimer suggest DVT but requires further testing to confirm the diagnosis because of the low specificity of the test; low specificity is caused by increase of the D-dimer because of other conditions including infection, inflammation, cancer, surgery and trauma etc.
Compression Ultrasonography (CUS)
in the presence of a positive D-dimer and high probability PTP, the next step is CUS
-it allows rapid clear visualization of thrombi, including identification of unstable or floating thrombi, which may cause emboli
What is the first step in treatment of DVT?
prevention
Treatment: Prevention
- in low risk patients, early ambulation may be all that is necessary
- Venous thromboembolism (VTE) prophylaxis is indicated in at-risk hospitalized populations
- in patients with a low bleeding risk, pharmacological prevention is recommended; preferred medications are low molecular weight heparin (LMWH), unfractionated heparin, or, in patients with heparin-induced thrombocytopenia (HIT), fondaparinux can be used
- in patients with a higher risk of bleeding mechanical VTE prophylaxis is indicated; includes use of graduated compression stockings, venous foot pumps, and active external intermittent compression devices
Intermittent Compression Devices
apply external pressure to the limb which which promotes blood flow velocity, reduces venous stasis, and increases levels of systemic fibrinolysis
Medications
consists of anticoagulation with unfractured heparin or low molecular weight heparin (LMWH) followed by long-term oral anticoagulation with warfarin
- these conventional anticoagulant therapies are widely used but have limitations
- require regular monitoring to maintain safe levels
- newer oral anticoagulant agents, including direct thrombin inhibitors (e.g dabigatran etexilate) and direct factor Xa inhibitors (e.g rivaroxaban, apixaban, and edoxaban) have been developed to overcome some of the limitations of conventional anticoagulant therapy
- thrombolytics are only used under certain circumstances; patients who have failed conventional therapy with a clot that has been present for fewer than 14 days and have a low bleeding risk, size and location of the clot and preexisting conditions
Safety Alert: Essential Teaching Points for patients on Warfarin
- Immediately report blood in sputum, emesis, stool, or urine
- take the medication at the same time everyday
- never skip a dose of medication
- have laboratory values (international normalized ratio (INR)) checked on a regular basis
- ensure that laboratory levels are safe to continue current dosage or change dosage
- limit intake or maintain a consistent intake of green leafy vegetables that contain vitamin K (kale, spinach, collard greens, broccoli, okra, cabbage) that may counteract the action of warfarin - limit any physical activities that will increase bleeding risk such as contact sports
- use an electric razor when shaving
- use a soft toothbrush
Signs + Symptoms with DVT: Calf thrombosis
- calf tenderness
- distal swelling of affected extremity
Signs + symptoms with DVT: Femoral thrombosis
- tenderness and pain in distal thigh and popliteal regions
- swelling more prominent than with calf vein thrombosis alone
- swelling may extend to the knee
Signs + Symptoms with DVT: Iliofemoral thrombosis
- massive swelling in affected extremity
- tenderness and pain involving enire extremity
Signs + Symptoms with DVT: Upper-extremity thrombosis
- swelling of affected extremity
- dilated superficial veins
- tenderness and pain
- impaired mobility of extremity
Surgical Management
rarely utilized in DVT unless there is a massive occlusion that does not respond to medical treatment and the thrombus is of recent (1-2 days) onset
- thrombectomy is most common surgical procedure for removing a clot
- other less-invasive surgical procedures include balloon angioplasty, stent placement, and vena cava interruption
Most common Surgical procedure for removing a clot
thrombectomy
Other less-invasive surgical procedures: Balloon angioplasty
widens the vein after a blood clot has been dissolved
-expanding the balloon in the vein causes the vein to widen and improves blood flow
Other less-invasive surgical procedures: Stent placement
stent insertion can be utilized for DVT patients who have a vein that is prone to collapse
-the stent expands once inserted and acts as a support for vein walls
Other less-invasive surgical procedures: Vena cava interruption
to prevent PE (pulmonary embolism)
- a provider surgically positions a filter inside the inferior or, no routinely, the superior vena cava between the DVT and the heart.
- blood flows normally through the umbrellalike filter, but emboli are trapped, ensuring that they do not reach the lungs
Complications
- pulmonary embolism (most serious life-threatening complication)
- post thrombotic syndrome (PTS)
Clinical Manifestations of a pulmonary embolism (PE)
-SOB
-decreased oxygen saturation
-tachycardia, hypotension
-sweating
-sharp chest pain (especially during deep breathing)
-hemoptysis (bloody sputum)
>these are due to the clot in the pulmonary vasculature blocking flow through the lungs preventing oxygenation and ventilation, increasing pulmonary vascular resistance (PVR), increasing the workload on the right heart, and decreasing oxygen supply to the lung tissue itself
Complication: Post thrombotic syndrome (PTS)
chronic disorder with clinical features that range from minor limb swelling and discomfort to severe leg pain, intractable edema, irreversible skin changes, and leg ulceration
- prevention of PTS with the use of thromboprophylaxis is important because treatments are not very effective
- elastic compression stockings have the potential to prevent PTS by reducing venous hypertension and reflux
Nursing Diagnosis
- ineffective peripheral tissue perfusion r/t interruption of venous blood flow
- acute pain r/t vascular inflammation and irritation and edema formation
- risk for impaired physical mobility r/t pain and discomfort of the affected extremities
Nursing Interventions: Assessment of Vital Signs with Oxygen Saturation
hypotension, tachycardia, and decreased oxygen saturation could indicate the presence of a PE or bleeding, especially if the patient is anticoagulated
Nursing Interventions: Assess extremity for pain, tenderness, warmth, redness, or swelling
common symptoms of DVT that occur because of obstruction of blood flow and may indicate location of the clot
Nursing Interventions: Compare right and left calf, thigh, or arm circumferences
localized edema due to obstruction to blood flow in one extremity may suggest a DVT
Nursing Interventions: Gentle palpation to inspect for induration
induration (hardening) helps to locate the placement of the clot in the blood vessel
Nursing Interventions: D-dimer test
measures fibrin degradation products produced from clot breakdown
-a positive result stratifies the patient into a high-risk category for DVT
Nursing Interventions: Laboratory Values: INR, PT/aPTT, hemoglobin, and hematocrit
-the INR and PT/aPTT should be prolonged
-the hemoglobin and hematocrit should be within normal limits
>the PT/INR evaluates the extrinsic coagulation cascade and is used to evaluate the effectiveness of warfarin
>the aPTT evaluates the intrinsic coagulation cascade and is used to evaluate the effectiveness of heparin
Nursing Interventions: Assess for signs of bleeding such as bruising, petechiae, hematuria, bloody stools
signs of bleeding may indicate a need to modify or decrease anticoagulation therapy
Nursing Interventions: Assessment
- Assess vital signs with oxygen saturation
- Assess extremity for pain, tenderness, warmth, redness, or swelling
- compare right and left calf, thigh, or arm circumference
- gentle palpation and inspect for induration (hardening)
- D-dimer test
- Laboratory values: INR, PT/aPTT, hemoglobin, hematocrit
- assess for signs of bleeding, such as bruising, petechiae, hematuria, and bloody stools
Nursing Actions
- early ambulation
- leg elevation
- compression stocking
- avoid use of SCDs in affected extremity
- encourage adequate fluid intake
- administer anticoagulation medications as ordered
- administer thrombolytic agent as ordered
Nursing Actions: early ambulation
bed rest has been recommended in the past but recent study shows early ambulation does not result in more complications
Nursing Actions: Leg elevlation
when at rest, the affected extremity should be elevated at least 10 to 20 degrees above heart level to enhance venous return and reduce swelling
Nursing Actions: Compression stockings
should be worn at all times
-compression promotes venous return and decreases leg swelling
Nursing Actions: Avoid use of SCDs in affected extremity
an SCD may cause the thrombus to break away resulting in an embolus
Nursing Actions: encourage adequate fluid inatke
prevents dehydration and sluggish blood flow, which exacerbates DVT growth
Nursing Actions: administer anticoagulation medications as ordered
anticoagulation with unfractionated heparin followed by long-term oral anticoagulation prevents formation of new thrombi and inhibits growth of the existing thrombi
Nursing Actions: administer thrombolytic agent as ordered
thrombolytic agents dissolve existing thrombi and decrease the instance of vascular damage
Nursing Teaching
- prevention of reoccurrence with activities
- signs and symptoms of bleeding such as bruising, bloody stools, petechiae
- compliance with regular laboratory monitoring
- safety precautions when taking anticoagulants
Nursing Teaching: prevention of reoccurrence with activities such as:
- early ambulation and active leg exercises
- monitor for adequate fluid intake to prevent dehydration and changes in blood flow
- avoid constricting clothing on the legs that might decrease venous flow, sitting with knees bent or crossed for long periods, standing for long periods
- remind patients that long car or airplane trips can increase risk of DVT, so they should stay well hydrated and move around whenever possible or do leg exercises while sitting
Nursing Teaching: Signs and symptoms of bleeding such as bruising, bloody stools, or petechiae
it is important when taking anticoagulants that the patient is able to detect signs and symptoms of bleeding
Nursing Teaching: Compliance with regular laboratory monitoring
important that the patient understands importance of laboratory draws and medication regimen to reduce bleeding risk
Evaluating Care outcomes
person with DVT can be safely managed by complying with prescribed anticoagulation therapy in combination with ambulation, compression stockings, and extremity elevation when resting
-stable vital signs and oxygenation saturation along with decreased pain, swelling, and tenderness
