pulmonary embolism Flashcards by Ezekiel McGinn

Describe what a pulmonary embolism is

An obstruction of the pulmonary artery or one of its branches by material that originated somewhere else in the body

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What material can cause a pulmonary embolism?

Blood clot
Air embolism
Tumor fragments
Fat
Amniotic fluid

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Describe why the location of a pulmonary embolism is so important

The location of the embolism determines how much of the lung or lungs are not receiving arterial blood. An embolism that cuts off blood flow to a small portion of a lobe is much less significant than an embolism that cuts off circulation to both lungs

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What is the most dangerous type of embolism?

A saddle embolism

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A pulmonary embolism can lead to infarction. What can this result in?

Alveolar atelectasis
Alveolar consolidation

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T/F: Advances in modern imaging have resulted the discovery of PE that would have otherwise gone undetected

True

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A pulmonary embolism can sometimes cause an inflammatory response. What can this lead to?

Bronchospasm
Seems to contribute to shunt like effect on top of PE deadspace for total effect of hypoxemia

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What is the incidence of PEs in the US?

38 cases per 100000 annually
100,000 deaths annually

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How does decreased perfusion affect surfactant production?

Decreases surfactant production

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What are the effects of decreased surfactant production as a result of a PE?

Decreased lung compliance
Atelectasis
V/Q mismatch

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What is thrombophlebitis?

Condition where a blood clot forms and blocks venous return, usually in the legs but it can occur throughout the body

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How does bone cancer increase the risk for a PE?

Bone cancers can lead to pathological fractures, the fractures can allow bone marrow to escape into blood stream, boom. PE

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Why are women who are pregnant at an increased risk of PE?

Enlarged uterus can result in obstruction of venous return resulting in stagnant blood that can form clots

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What pathological malignancies increase risk for PEs?

Multiple myeloma (bone cancer)
Tumors

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How do tumors increase the risk for PE?

Potential fragmentation into bloodstream
Tumor can release procoagulant factors

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Why are patients in the hospital at an increased risk for developing a PE?

They are immobilized
Potentially hypercoagulable states
Frequently have undergone major surgery

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What other factors and conditions can increase risk of a PE?

Obesity
Childbirth
Supplemental estrogen
Family history of venous thromboembolism
Smoking
Burns
Pacemakers or venous catheters

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What can lead to hypercoagulation?

Oral contraceptives
Polycythemia (increased RBC count)
Factor V leiden (genetic disorder that increased chances of forming clots)

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Where do most clots form?

Most clots originate or break away from sites of deep venous thrombosis in the lower part of the body
Leg, pelvic veins, inferior vena cava

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What is venous stasis and how does it contribute to clot formation?

Slowing or stagnation of blood flow through the veins
Stagnating blood has a higher risk of coagulation

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What hemodynamic indices would we see on a PE patient who is crashing?

Decreased CO
Systemic hypotension
Increase PVR

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How does injury to the endothelial cells increase the risk for clot formation?

Activation of the platelets to form a clot which can then break off

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How would a patient who is crashing as a result of PE present?

Sudden onset of dyspnea, tachycardia and hypotension
Hypotension
Weak pulse
lightheaded/fainting
Anxiety
Cyanosis

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Describe chest pain that is caused by a PE

May be pleuritic
May radiate
Can be sharp, stabbing, aching or dull
May intensify with exertion
Does not subside with rest

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Describe the sputum that a patient with severe PE might produce

Bloodstreaked

T/F: a patient in critical condition with a PE may produce a wheeze

True

Describe how septic emboli form and what can happen as a result of their formation

Vegetations form on the tricuspid or pulmonary valve in the heart Vegetations fragment and lodge themselves in pulmonary arteries Vegetations fragment causing infections, abscesses, cavities and infarcts, oh my!

What hemodynamic indices would decrease as a result of a PE?

CO SV

What population is at risk for developing septic emboli?

IV drug users

What hemodynamic indices would increase as a result of a PE?

CVP RAP PA PVR

T/F: A chest radiograph is useless for diagnosing a PE

False. While the CXR cannot determine if the patient has a PE, it can be useful for ruling out other potential causes of dyspnea.

What can a CXR show in some patients with PE?

Dilated right ventricle Right ventricular hypertrophy

What is the gold standard for diagnosing a PE?

Computed tomography pulmonary angiogram

What are some of the risks associated with CTPA?

Contrast can cause damage to the kidneys Exposes the patient to radiation

Describe how a CTPA helps us locate a PE

Contrast is injected into the veins to make the pulmonary vasulature appear white which allows us to see blockages

What can be used to look for a PE if a CTPA isnt available or the patient has kidney disease/can take contrast?

A V/Q scan

How is a V/Q scan performed?

Ventilation scan = patient inhales nebulized radioisotope and is scanned with nuclear medicine camera to visualize the airways Perfusion scan = patient is injected with a radioisotope and scanned to image pulmonary vasculature The two images are then compared for mismatches

How can ultrasonography be used to detect PEs?

Ultrasound imaging of the lower extremities can detect deep venous thrombosis Cardiac ultrasound can detect right heart strain

What does the D-Dimer test for?

A protein fragment that is left in the blood after a clot is dissolved by fibrinolysis

What blood test can be utilized to determine someones risk for a PE?

D-Dimer

What concentration of D-Dimer is an indication for increased potential of PE?

Greater than or equal to 500 ng/mL

Describe why the D-Dimer test may not be particularly useful in testing for PEs?

Many things can raise the D-dimer such as recent surgery or injury Just because they have a high D-dimer level does not necessarily mean they are at risk for developing a PE

A score of greater than 6 on the wells score is indicative of what?

High probability of PE

When using the Wells score, what symptoms and factors are considered for scoring?

Symptoms of DVT No better alternative diagnosis Tachycardia > 100 Immobilization of surgery in the past 4 weeks Prior history of DVT or PE Presence of hemoptysis Presence of malignancy

A score of between 2-6 on the wells score is indicative of what?

Moderate probability of PE

A score of less than 2 on the wells score is indicative of what?

Low probability of PE

What are the 2 scoring systems when considering PE?

Wells score PERC (Pulmonary embolism rule out criteria)

What is PERC (pulmonary embolism rule out criteria) used for?

Similar to the pneumonia severity index, it helps clinicians determine whether or not a patient can be sent home

T/F: A patient does not need to be considered low risk in order to use PERC

False. The provider must feel that the patient is low risk in order to apply PERC

What is the procedure of the patient passes PERC?

They are ok to send home

What is the procedure if the patient is flagged by PERC?

they are usually given a D-dimer test which may or may not lead to imaging

What are the criteria for the PERC?

Age > 50 HR > 100 SpO2 on RA <95% History of venous thromboembolism Trauma or surgery in the last 4 weeis Hemoptysis Exogenous estrogen Unilateral leg swelling

Describe the classic presentation for PE

Sudden onset dyspnea Sudden increase in HR Sudden systemic hypotension Cough, hemoptysis, pleuritic chest pain Distress Diaphoresis Recent surgery or extended travel

T/F: A patient with a PE may have distended neck veins

True, the embolism may be causing significant backup of blood flow resulting in venous distention

T/F: a Patient with a PE may have a swollen and tender liver

True, a symptom of blood back up

What might be detectable on a patient with a PE who has significant pulmonary hypertension?

Right ventricular lift

Describe a thrombectomy

Surgical option for hemodynamically unstable patients A catheter is advanced through the right femoral vein Clot is broken up mechanically, chemically, or suctioned out Relatively high rate of mortality \

What patients with PEs are considered acute?

Hemodynamically unstable patients are considered acute

How is acute PE typically managed?

Surgery Thrombolytics Anticoagulants

What can be concerning regarding thrombolytics?

Thrombolytics actively break down clots but do so indiscriminately throughout the body, which is problematic if you are prone to bleeding? Ask steve

What is the most common thrombolytic used?

Tissue plasmin activator (tPA) Aka alteplase

What is the purpose of anticoagulants when dealing with PEs?

The can help keep the clot from growing Keep more clots from forming

How are stable PEs managed?

Heparin Supportive care including supplemental oxygen

How are anticoagulants delivered to during treatment of a PE?

Unfractionated heparin delivered via IV

How are stable PEs treated long term with anticoagulants? What drugs are used?

Anticoagulant therapy = warfarin (coumadin) Direct oral anticoagulants Eliquis (apixaban) Xarelto ( rivaroxaban) Pradaxa (dabigatran)

How are stable PEs treated long term with blood thinners? What drugs are used?

Low molecular weight heparins taken orally Enoxaparin (lovenox) most common

What device can be used to help prevent PEs?

Inferior vena cava filter aka greenfield filter

What are some complications associated with the greenfield filter?

Device migration Filter fracture Insertion site thrombosis Perforation of vena cava Thrombotic complications Having a literal spaghetti strainer in your IVC seems bad

Describe non-invasive and non-pharmacological management strategies for mitigating PE risk

Walking Exercise while seated Drink fluids Graduated compression stockings Pneumatic compression of legs in hospital