Problems with Perfusion: Pulmonary Emboli & V/Q Mismatch

Describe the pathway of pulmonary circulation.

• Blood flows through the lungs from the right side of the heart to pick up oxygen and get rid of carbon dioxide

• Blood flows from the lungs back to the left side of the heart to be pumped out to the rest of the body

What is a pulmonary embolism? What problems does it cause?

A blood clot that gets into blood vessels in the lungs and prevents normal flow of blood in that area.

The blockage causes problems with gas exchange. Depending on how big of a clot and the number of vessels involved, it can be life threatening.

What is the definition of an embolism? Where do they typically originate?

A blood clot (or multuple) that has broken off and is floating freely in the blood vessel, usually pulmonary artery.

Typically origionates in a LE as a deep vein thrombosis (DVT)

____ are stationary, while _____ are mobile.

Clots stationary

Emboli mobile

What is the only artery that carries deoxygenated blood? What does it do?

• Pulmonary arteries carry blood from the heart to the lungs

• The only arteries in the body that carry deoxygenated blood

• The main pulmonary artery (pulmonary trunk) leaves the RIGHT ventricle at the pulmonary valve and splits int o the right and left pulmonary arteries, which carry blood to each of the lungs.

What problems do blood clots cause when they lodge into a pulmonary artery?

• Blocks the flow of deoxygenated blood to the lung (gas not exchanged, lungs not perfused)

• Severity depends upon how much blood flow is reduced

• If an inadequate amount of blood gets oxygenated and moves to the left side of the heart, the O2 level in the body drops dangerously low, causing stress and damage to all of the organs in the body.

What major organs are affected by blood clots and subsequent low O2 levels?

• Brain

• Kidneys

• Heart

What are the risk factors for a PE?

• Inherited condition such as Factor V Leiden

• Abnormal blood vessles (vericose veins)

• Pregnancy or 6 weeks S/P delivery

• Smoking

• Obesity

• Extended time in cars or airplanes without moving >4-6 hours

• Prolonged bed rest after a major surgery

• Older age

• People with prior hx of blood clot

• Oral contraceptives/hormonal pills

• Failure to take blood thinners as prescribed

List the 3 categories of PE.

1) Acute: common condition that can be difficult to diagnose because symptoms vary

2) Subacute: can develop gradually and difficult to diagnose; can mean there may be delays in treatment and poorer outcomes - higher mortality rate than acute PE

3) Chronic: residual blood clots can remain attached to the walls of the pulmonary vessels after treatment; can result in chronic thromboembolic pulmonary hypertension (CTEPH)

What is a saddle PE?

• A saddle PE is a larger and more unstable blood clot

• Has increased risk of breaking up and causing blockages further down into the right and left pulmonary arteries, or other parts of the lungs

What are the most common signs and symptoms of a PE?

• Dyspnea

• Pleuritic chest pain

• Cough

• Chest pain

• Hemoptysis or blood-streaked saliva

• Tachycardia

• Dysrhythmias

• Hypotension (lack of perfusion)

• Lightheadedness or dizziness

• Fever

• Diaphoresis

• Cyanosis

• Leg pain or swelling (if DVT)

• Change in LOC

How soon after the onset of PE symptoms does death occur?

Death occurs within 1 hour of the onset of symptoms in most cases - so early diagnostics!

Describe the normal findings and reason for using VQ scan for the diagnosis of PE.

V/Q scan: evaluates the different regions of the lung and allows comparisons of the percentage of ventilation and perfusion in each area

Describe the typical findings and reason for using chest x-rays for the diagnosis of PE.

Chest x ray: usually normal but may show infiltrates, atelectasis and the elevation of the diaphragm on the affected side, or pleural effusion

Describe the normal findings and reason for using ECG for the diagnosis of PE.

ECG: usually shows tachycardia, PR interval depression, and non-specific T wave changes

Describe the normal findings and reason for using ABG analysis for the diagnosis of PE.

ABG analysis: may show hypoxemia and hypocapnia, but may be normal even in the presence of a PE

Describe the normal findings and reason for using pulmonary angiogram for the diagnosis of PE.

Pulmonary angiogram: allows for direct visualization under fluoroscopy of the arterial obstruction and accurate assessment of the perfusion deficit (x ray of vessels to show lack of perfusion or clot)

What is a VQ ratio?

2 part test

• Ventilation: a small amount of radioactive particles (tracer) are inhaled. the bright tags of the tracer make the air flowing into your lungs show up on nuclear med images

• Perfusion: an injection of similar tracer via IV. images of blood flow through the lungs are taken

What is a CT angio? Why do we use it to diagnose a PE? What nursing considerations do we need to remember?

• CT Pulmonary Angiography (CTPA)

• NURSING: 20 G OR BIGGER IV IN LARGE VEIN

• Will show a filling defect within the pulmonary vasculature with acute pulmonary emboli

• Complete blockage and incomplete blockage are both identifiable with this diagnostic

What is a D-Dimer test? What does it tell us?

• Screening exam that looks for a protein fragment that your body makes when a blood clot dissolves

• Normally undetectable or only detectable at very low levels unless the body is forming and breaking down significant blood clots

• A positive screen can’t reveal what type of clotting condition is present or where the clot is located

• NOT DIAGNOSTIC - SCREENING ONLY

What things are measured on a Coagulant Panel? What do they mean?

PT/INR (Prothrombonin Time)

• Prothrombonin is a protein produced by your liver

• Increased values indicate more time is needed to clot

• Coumadin will increase clotting time, meaning it is harder to clot

PTT (Partial Thromboplastin Time)

• PTT tests the function of all clotting factors except for factor VII (tissue factor) and factor XIII (fibrin stabilizing factor)

If a patient has a high D-Dimer, high PT and high PTT, what do we suspect?

Clotting disorder or potential PE

What is the initial approach to patients with a suspected PE?

• Stabilize the patient

• Clinically evaluate

• Diagnostic tests

• Anticoagulant therapy

• Once diagnosis is confirmed, risk stratification is crucial.

What is thrombectomy?

A surgery to remove a blood clot from a blood vessel (artery or vein).

What is an IVC filter? Who is a good candidate for IVC filters?

Placement of an inferior vena cava (IVC) filter may be a required for a deep vein thrombosis (DVT). Vena cava filters may be temporary or permanent; the decision is based on an individualized basis. These filters are reserved for patients who are unable to take blood-thinning medications or for those at high risk for developing recurrent DVT with pulmonary embolism (PE).

What prevention measures do we encourage as nurses?

Avoid venous stasis:

• Ensure patients engage in active leg exercises

• Early ambulation

• Anti-embolism stockings/SCDs

• Anticoagulant therapy: prescribed for patients whose hemostasis is adequate and who are undergoing major elective abdominal or thoracic surgery as prevention

What respiratory support do we provide for a patient with PE?

• Supplemental O2 should be administered to target an oxygen saturation above 90%

• Severe hypoxemia, hemodynamic collapse, or respiratory failure should prompt consideration of intubation and mechanical ventilation

What should we look out for after intubating a patient that also has co-existent right ventricle failure?

Patients with co-existant right ventricle failure are prone to hypotension following intubation

What sequelae, or associtated complications of a PE, should you assess for?

• Cardiogenic shock: the cardiopulmonary system is endangered in a massive PE

• Vital sign changes

• Right ventricular failure: a sudden increase in pulmonary resistance increases the work of the right ventricle

• Peripheral edema

• SOB

What are signs of right sided heart failure?

• Fatigue

• Increased peripheral venous pressure

• Ascites

• Enlarged liver and spleen

• Distended jugular veins

• Anorexia and complaints of GI distress

• Swelling in hands and fingers

• Dependent edema

What nursing care would we provide for a patient with a PE?

• Monitor thrombolytic therapy: monitoring thrombolytic and anticoagulant therapy through INR and PTT

• Manage pain: turn the patient frequently and reposition to improve the 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