pulmonary embolism pathophysiology

1. Pulmonary Embolism

2. Definition

Pulmonary embolism is a blockage in one of
the pulmonary arteries in your lungs. In most
cases, pulmonary embolism is caused by blood
clots that travel to the lungs from the legs or,
rarely, other parts of the body (deep vein
thrombosis).

It can damage part of the lung due to restricted
blood flow, decrease oxygen levels in the blood,
and affect other organs as well. Large or
multiple blood clots can be fatal.

3. Primary Cause(s)

Three primary influences predispose a patient
to thrombus formation; these form the so-called
Virchow triad, which consists of the following

Endothelial injury

Stasis or turbulence of blood flow

Blood hypercoagulability

4. Other Causes (Multifactorial)

Venous stasis leads to accumulation of platelets and thrombin in
veins.

Concomitant hypercoagulability may be present in disease states
where prolonged venous stasis or injury to veins occurs.
Hypercoagulable states may be acquired or congenital.

Immobilization leads to local venous stasis by accumulation of
clotting factors and fibrin, resulting in thrombus formation.

Surgical and accidental traumas predispose patients to venous
thromboembolism by activating clotting factors and causing
immobility. Pulmonary embolism may account for 15% of all
postoperative deaths. Leg amputations and hip, pelvic, and spinal
surgery are associated with the highest risk.

5. Other Causes (Multifactorial)

Pregnancy - the incidence of thromboembolic disease in pregnancy
has been reported to range from 1 case in 200 deliveries to 1 case in
1400 deliveries

a family history of embolisms

a history of heart attack or stroke

obesity

a sedentary lifestyle

age over 60 years

Estrogen-containing birth control pills have increased the occurrence
of venous thromboembolism in healthy women. The risk is
proportional to the estrogen content and is increased in
postmenopausal women on hormonal replacement therapy.

cancer

6. Pathophysiology

7. Signs and Symptoms

Shortness of Breath – most common

anxiety

clammy or bluish skin

chest pain that may extend into your arm, jaw, neck, and shoulder

fainting

irregular heartbeat

light-headedness

rapid breathing

rapid heartbeat

restlessness

spitting up blood

weak pulse

9. Complications

10. Diagnosis/Tests

Pulmonary embolism can be difficult to
diagnose, especially in people who have
underlying heart or lung disease. For that
reason, your doctor will likely order one or more
of the following tests.

11. Diagnosis/Tests

D-dimer test – a clot-dissolving substance. High
levels may suggest an increased likelihood of
blood clots

ABG test - measures the amount of oxygen and
carbon dioxide in your blood

Blood test to confirm if patient has a inherited
clotting disorder

12. Diagnosis/Tests

Chest X-ray- this noninvasive test shows images of your heart and
lungs on film. Although X-rays can't diagnose pulmonary embolism
and may even appear normal when pulmonary embolism exists, they
can rule out conditions that mimic the disease.

13. Diagnosis/Tests

Ultrasound-A noninvasive test known as duplex
ultrasonography (sometimes called duplex
scan, or compression ultrasonography) uses
sound waves to check for blood clots in your
thigh veins.

14. Diagnosis/Tests

Spiral CT scan - this type of CT can detect
abnormalities within the arteries in your lungs
with much greater precision than conventional
CT scans. In some cases, contrast material is
given intravenously during the CT scan to
outline the pulmonary arteries.

15. Diagnosis/Tests

Pulmonary angiogram

This test provides a clear picture of the blood
flow in the arteries of your lungs. It's the most
accurate way to diagnose pulmonary embolism,
but because it requires a high degree of skill to
administer and has potentially serious risks, it's
usually performed when other tests fail to
provide a definitive diagnosis.

One risk of this procedure is a temporary
change in your heart rhythm. In addition, the
dye may cause kidney damage in people with
decreased kidney function.

17. Diagnosis/Tests

MRI-use radio waves and a powerful magnetic
field to produce detailed images of internal
structures. Because MRI is expensive, it's
usually reserved for pregnant women (to avoid
radiation to the fetus) and people whose
kidneys may be harmed by dyes used in other
tests.

18. Treatment

Medications
− Blood thinners (anticoagulants). These drugs
prevent new clots from forming while your
body works to break up the clots.

Heparin
− Clot dissolvers (thrombolytics). While clots
usually dissolve on their own, there are
medications given through the vein that can
dissolve clots quickly. Because these clot-
busting drugs can cause sudden and severe
bleeding, they usually are reserved for life-
threatening situations.

19. Treatment

Surgical Intervention
− Clot removal. If you have a very large, life-threatening clot
in your lung, your doctor may suggest removing it via a
thin, flexible tube (catheter) threaded through your blood
vessels.
− Vein filter. A catheter can also be used to position a filter in
the body's main vein — called the inferior vena cava —
that leads from your legs to the right side of your heart.
This filter can help keep clots from being carried into your
lungs. This procedure is typically reserved for people who
can't take anticoagulant drugs or when anticoagulant drugs
don't work well enough or fast enough. Some filters can be
removed when they are no longer needed.
− Embolectomy - either catheter embolectomy and
fragmentation or surgical embolectomy is reasonable for
patients with massive pulmonary embolism who have
contraindications to fibrinolysis or who remain unstable
after receiving fibrinolysis.

20. Treatment

Nursing Interventions
− Prevent venous stasis. Encourage ambulation and
active and passive leg exercises to prevent venous stasis.
− Monitor thrombolytic therapy. Monitoring thrombolytic
and anticoagulant therapy through INR or PTT.
− Manage pain. Turn patient frequently and reposition to
improve ventilation-perfusion ratio.
− Manage oxygen therapy. Assess for signs of hypoxemia
and monitor the pulse oximetry values.
− Relieve anxiety. Encourage the patient to talk about any
fears or concerns related to this frightening episode.

21. Discharge and Home Care Guidelines
After discharge, there are some guidelines that the nurse must teach the
patient.

Prevent recurrence. The nurse should instruct the patient about
preventing recurrence and reporting signs and symptoms.

Adherence. The nurse should monitor the patient’s adherence to
the prescribed management plan and enforces previous instructions.

Residual effects. The nurse should also monitor for residual effects
of the PE and recovery.

Follow-up checkups. Remind the patient about keeping up with
follow-up appointments for coagulation tests and appointments with
the primary care provider.