pulmonary embolism Flashcards
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
What material can cause a pulmonary embolism?
Blood clot
Air embolism
Tumor fragments
Fat
Amniotic fluid
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
What is the most dangerous type of embolism?
A saddle embolism
A pulmonary embolism can lead to infarction. What can this result in?
Alveolar atelectasis
Alveolar consolidation
T/F: Advances in modern imaging have resulted the discovery of PE that would have otherwise gone undetected
True
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
What is the incidence of PEs in the US?
38 cases per 100000 annually
100,000 deaths annually
How does decreased perfusion affect surfactant production?
Decreases surfactant production
What are the effects of decreased surfactant production as a result of a PE?
Decreased lung compliance
Atelectasis
V/Q mismatch
What is thrombophlebitis?
Condition where a blood clot forms and blocks venous return, usually in the legs but it can occur throughout the body
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
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
What pathological malignancies increase risk for PEs?
Multiple myeloma (bone cancer)
Tumors
How do tumors increase the risk for PE?
Potential fragmentation into bloodstream
Tumor can release procoagulant factors
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
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
What can lead to hypercoagulation?
Oral contraceptives
Polycythemia (increased RBC count)
Factor V leiden (genetic disorder that increased chances of forming clots)
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
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
What hemodynamic indices would we see on a PE patient who is crashing?
Decreased CO
Systemic hypotension
Increase PVR
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
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
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
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
