1. DVT & PE Cindy Fehr Malaspina University-College BSN Nursing Program
Nursing 335 – Fall 2005

2. FACTS Orthopedic injuries place at  risk
DVT – formation of thrombus in deep vein, typically in lower extremity
PE – thrombus that travels into the pulmonary circulation

3. Pathophysiology of DVT
Prevention is key
Identify those at high risk
Virchow’s triad  changes in blood coagulability, changes in vessel wall, changes in blood flow
Prophylactic tx with oral anticoagulant or LMW heparin
Intermittent pneumatic compression devices (calf compressors) or elastic stockings (TEDS)
Early ambulation
Early identification & treatment of DVTs
treat with vena cava filters
Virchow’s triad:
1. venous stasis or obstruction
2. overt vessel injury
3. intravascular conditions such as intimal irritation; roughening, inflammation, infection, and abnormalities of coagulation or fibrinolysis

4. Coagulation Pathways
Extrinsic Pathway - activated when tissue trauma occurs
Intrinsic Pathway - activated under conditions such as stress, anxiety, or fear, and in the absence of external tissue injury
stage one cascade - either the intrinsic or extrinsic pathway ends with the formation of prothrombin-converting factor
stage two prothrombin-converting factor begins series of chemical interactions  slowly converts prothrombin to thrombin.
Stage three fibrinogen interacts with thrombin to form fibrin.
erythrocytes, phagocytes, and microorganisms, also collect at the site to complete thrombosis development

5. predisposing factors of DVT
* advanced age
* trauma
* spinal cord injury
* immobilization
* myocardial infarction
* heart failure
* stroke
* previous thromboembolic disease
* thrombotic abnormalities
* obesity
* pregnancy
* constricted clothing
* homocystinuria
* systemic lupus erythematosus
* inflammatory bowel disease
* central venous catheter use
* oral estrogen use

6. Pulmonary Embolism About 10% of PEs result in immediate death
a futher 20% kill later if they're untreated
Once treated, the mortality rate drops to 3%.

7. Source: Nucleus Medical Art Online

8. Venous thromboembolism (PE)
a serious and common problem that can and should be prevented
A serious problem:
80% of PE occur without signs
2/3 of deaths occur within 30 minutes
A common problem:
One in 100 hospitalized patients dies of PE
Can & should be prevented

9. These pulmonary emboli removed at autopsy look like casts
of the deep veins of the leg where they originated.
Source:

10. What increases the chances of having a pulmonary embolism?
Older adults, especially those who are bedridden
People who have or have had cancer
Anyone who has recently undergone surgery, especially in the abdomen
Family history of pulmonary embolism
Obesity
Recent fracture of the pelvis or legs
Pregnant women and women who have recently given birth
Oral contraceptive use

11. The main symptoms of a Pulmonary Embolus are:
Chest pain
Typically under the breastbone or to one side
Typically a sharp stabbing pain
Typically made worse when breathing in
Shortness of breath
A mild temperature (typically 38°C), with sweating
Rapid pulse
A dry cough, sometimes with blood (usually small amounts, sometimes more)
A feeling of anxiety

12. There are three main tests which can be performed:
D-dimer: represents fibrin split products that are released into the blood stream when there are clots in the blood stream
Chest X-ray: helpful to eliminate other possibilities, but 25% of PEs don't show up on an ordinary x-ray
Ventilation Perfusion scan (V/Q scan): good initial screening test, but notoriously difficult to analyse
CT scan: the definitive diagnostic tool
Source: American Family Physician Journal Sept. 2001

13. Treatment to thin the blood using anti-coagulants.
initial injection (bolus) of heparin, followed by a heparin infusion for several days
although heparin provides immediate protection, it has an extremely low half-life, so it only protects you while you're being infused with it
a longer-lasting anti-coagulant is used for ongoing protection. (warfarin)
on heparin until blood tests (INR test) confirms that warfarin is keeping your blood two or three times thinner than usual

14. Treatment cont. Less common treatments include
These options are used when anti-coagulation is proving ineffective or where the clot is so severe that it is too dangerous to wait for the clots to dissolve in the thinned blood
clot-filters
clot-busting drugs
surgery

15. Prevention
To help prevent development of blood clots in the venous system
Pressure stockings
early ambulation
low dose heparin
use of sequential compression