DVT & PE

Cindy FehrMalaspina University-College

BSN Nursing ProgramNursing 335 – Fall 2005

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

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

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

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

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%.

Source: Nucleus Medical Art Online

Venous thromboembolism (PE)

• a serious and commonproblem 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

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

Source: www.DVT.ORG

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

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

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

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

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

Prevention

• To help prevent development of blood clots in the venous system

• Pressure stockings• early ambulation • low dose heparin • use of sequential compression