Transcript What You Need to Know About Venous Thromboembolism

What You Need to Know about
Venous Thromboembolism
By Bill Pruitt, RRT, AE-C, CPFT, MBA
and Robin Lawson, RN, DNP
Nursing2009, April 2009
2.3 ANCC contact hours
Online: www.nursingcenter.com
© 2009 by Lippincott Williams & Wilkins. All world rights reserved.
What is venous
thromboembolism (VTE)?
 An occlusion in a vein caused by a
thrombus (most common)
 An embolus of an air bubble, fat
droplets, amniotic fluid, clumps of
parasites, tumor cells (less common)
 In I.V. drug users, a foreign substance
such as talc can lead to VTE
Where does VTE occur?
 Typically in leg veins
 2% to 3% occur in arms
 Pulmonary embolism can occur when
part of a deep vein thrombosis (DVT)
breaks loose and travels through the
right side of the heart into pulmonary
artery
Pulmonary embolism (PE)
 PE occludes blood flow to part of the
lung and impairs gas exchange
 Affected portion of lung becomes
necrotic and impairs oxygen delivery to
other body tissues
 90% of all PEs come from thrombi in the
popliteal vein and larger veins above it
What happens in DVT and PE
 When DVT obstructs venous circulation
in a leg, collateral circulation may
develop rapidly
 Patient may have few signs and
symptoms; when they develop, are
related to local inflammation and local
tissue ischemia as well as degree of
venous outflow obstruction
What happens in DVT and PE
 Complications of DVT include venous
valvular damage, chronic venous
insufficiency (chronic pain, swelling,
cramping, skin discoloration, ulceration
in affected limb), PE
 PE obstructs blood flow in pulmonary
arterial system
What happens in DVT and PE
 Pathologic changes depend on degree of
obstruction and patient’s condition
 If blood flow is obstructed in gas
exchange areas of lung (alveoli and
respiratory bronchioles), you’ll see V/Q
mismatch and increased physiologic
dead space ventilation
What happens in DVT and PE
 Extensive PE causes large area of dead
space ventilation, imposing increased
work on right ventricle as a result of
obstructed right ventricular outflow and
pulmonary vasoconstriction from release
of vasoactive mediators
What happens in DVT and PE
 Increased right ventricular afterload
results in right ventricular hypertrophy
and decreased right ventricular ejection
fraction. Ventricle becomes ischemic and
may eventually progress to right
ventricular failure
Risk factors
 Hereditary: deficiency in antithrombin,
protein C, protein S, or plasminogen
 Acquired: surgery, trauma, advanced
age, cancer, reduced mobility, smoking,
use of oral contraceptives, pregnancy
Assessing a patient’s VTE risk
 Scoring systems based on patient’s
clinical characteristics can estimate
patient’s likelihood of developing VTE
 Wells prediction rule for DVT, Wells and
Geneva prediction rules for PE provide
probability ranking for VTE based on
history of DVT or PE, cancer, recent
surgery/immobilization, age, heart rate
Assessing a patient’s VTE risk
 Based on type and number of risk
factors, patient’s level of risk can be
classified as low, moderate, or high as
stipulated in 2008 ACCP guidelines
 Appropriate prophylactic treatment can
start based on ACCP recommendations.
Risk assessment is ideally incorporated
into initial assessment form
Comparing VTE Risk
Level of risk
 Low: mobile patients undergoing minor
surgery; medical patients who are fully
mobile
 Moderate: patients undergoing general
surgery or open gynecologic or urologic
surgery; medical patients who are sick
or on bed rest
Comparing VTE Risk
Level of risk
 High: patients undergoing hip or knee
arthroplasty or hip fracture surgery;
patients with major trauma or spinal
cord injury
Comparing VTE Risk
Risk of DVT if no prophylaxis is given
 Low: less than 10%
 Moderate: 10% to 40%
 Moderate plus high bleeding risk: 10%
to 40%
 High: 40% to 80%
 High plus high bleeding risk: 40% to
80%
Comparing VTE Risk
Suggested prophylaxis
 Low: no specific prophylaxis; early and
aggressive ambulation
 Moderate: low-molecular-weight heparin
(LMWH) at recommended doses, lowdose unfractionated heparin 2 or 3
times/day, or fondaparinux
Comparing VTE Risk
 Moderate plus high bleeding risk:
mechanical prophylaxis with intermittent
pneumatic compression,venous foot
pump, graduated compression stockings
 High: LMWH at recommended doses,
fondaparinux, oral vitamin K antagonists
to maintain INR between 2 and 3
 High, plus high bleeding risk:
mechanical prophylaxis as above
Recognizing VTE
 Patient with DVT: edema, pain, warmth in
one leg, venous stasis ulcers, venous
varicosities, venous insufficiency
 Patient with PE: dyspnea, hemoptysis,
cough, wheezes, tachypnea, pulmonary
crackles, chest pain, palpitations,
tachycardia, lightheadedness; suspect
massive PE with sudden hypotension,
syncope, severe hypoxemia, cardiac arrest
Diagnosing VTE
 Based on patient’s risk factors, physical
assessment findings, diagnostic study
results
 Physical assessment for DVT: examine
patient’s legs, noting erythema,
tenderness, pain; palpation could
dislodge and cause PE
Diagnosing VTE
 D-dimer: normal value less than 500
ng/mL; if high, needs duplex ultrasound
 Duplex ultrasound: two-dimensional
ultrasound with Doppler; provides vein
images, blood flow measurements; loses
accuracy in calf vein
 Contrast venography: gold standard;
invasive with potential complications
Is it PE?
 Diagnostic testing aimed at:
- confirming condition
- defining severity
- ruling out conditions that mimic PE
(pneumonia, myocardial infarction)
 If massive PE suspected, treatment
takes priority over testing
Diagnosing PE
 Chest X-ray: helps rule out other causes
 ECG: useful for ruling out cardiac causes;
may show ST, T wave changes
 Arterial blood gases: will show ventilation
perfusion mismatch
Diagnosing PE
 D-dimer: can help rule out PE
 Spiral computed tomography pulmonary
angiography; can help confirm diagnosis
of PE and rule out other causes
Preventing VTE after surgery
 Risk depends on type of surgery,
presence of other risk factors
 Procedures with prolonged immobility
are at highest risk: orthopedic,
neurosurgery, major vascular surgery,
major abdominal or pelvic surgery
Preventing VTE after surgery
 Latest guidelines from ACCP
recommend all hospitals develop
formal prevention strategy to include:
- computerized decision support
- preprinted or standing orders
- regular audits to monitor adherence
 Guidelines recommend against using
aspirin alone and early ambulation in
low-risk general surgery patients
Treating VTE
 Anticoagulants, warm compresses, leg
elevation are first-line treatment
 Oxygen, ventilation, I.V. fluids, fibrinolytics
may be ordered for PE
 Vena cava filter may stop traveling thrombi
 Embolectomy: for patients with massive PE
who don’t respond to fibrinolytics
Inferior vena cava (IVC) filter
 Some newer filters are called retrievable
or optional filters
 Can be retrieved after a period or left in
permanently
 Recommended for patients with
documented VTE who have difficulty
receiving full-dose anticoagulation
Prevention
 Hospitalized patients should be routinely
assessed for VTE risk
 Measure and use graduated
compression stockings correctly
 Make sure pneumatic compression
devices function properly
Prevention
 Explain importance of these devices to
patient
 Encourage early ambulation after
surgery
 Surgical patients on unfractionated
heparin will need baseline aPTT,
hematocrit, and platelet counts
Prevention
 If long-term anticoagulation is needed,
warfarin will be started for 4 to 5 days
before heparin is discontinued
 Heparin discontinued when INR is in
therapeutic range (2.0 to 3.0) on two
consecutive measurements 24 hrs apart
 Monitor patient for signs of bleeding
Educating your patient
 Teach patient risk factors for DVT
 Teach preventive measures
 Instruct patient to call HCP if signs and
symptoms of DVT develop
Warfarin therapy patient
education
 Eat limited foods high in vitamin K
 Keep blood work appointments
 Check with HCP or pharmacist before
taking vitamin supplements
Warfarin therapy patient
education
 Limit alcohol intake
 Alert HCP about anticoagulant therapy
before undergoing medical procedures
 Protect from injury (soft toothbrushes,
electric razors) due to bleeding/bruising
Warfarin therapy patient
education
 Stop smoking, lose weight, drink lots of
fluids
 Women should not use oral
contraceptives if history of DVT/PE
Travel
 Long air flights, car rides linked to DVT/PE
 ACCP recommends anyone sitting for
more than 8 hours avoid constrictive
clothing and stay hydrated
 For patients at high risk for DVT, wear
graduated compression stockings or
receive single dose of LMWH before
departure