Pulmonary Embolism Flashcards
What is a pulmonary embolism (PE)?
It is defined as a condition in which there is formation of a clot within the pulmonary arteries
What is the pathophysiological cause of pulmonary embolisms?
The clot formation tends to occur secondary to deep vein thrombosis, in which a thrombus within the deep veins of the lower leg embolises and travels to the right side of the heart and pulmonary arteries
What is the pathophysiological consequence of pulmonary embolisms?
The thrombus will block the blood flow to the lung tissue and create strain on the right side of the heart
What twelve risk factors are associated with pulmonary embolisms?
Older Age
Family History
Obesity
Pregnancy
Immobility
Hospitalisation
Malignancy
Thrombophilia
Antiphospholipid Syndrome
Polycythaemia
Drug Administration
Central Venous Catheter
Which six drugs are associated with pulmonary embolisms?
Combined Oral Contraceptive Pill
Hormone Replacement Therapy
Tamoxifen
Raloxifene
Antipsychotics
Anaesthesia
In order to prevent pulmonary embolism, what advice should individuals on the combined oral contraceptive pill recieve before surgery?
They should stop taking the combined oral contraceptive pill 4 weeks before surgery and use alternative contraceptive methods
What are the seven clincial features of pulmonary embolisms?
Low Grade Fever
Dyspnoea
Pleuritic Chest Pain
Haemoptysis
Bibasal Lung Crackles
Tachycardia
Tachypnoea
In exams, how does pulmonary embolism tend to present?
The patient presents with respiratory clincial features - however the chest examination is normal
What eight investigations are used to diagnose pulmonary embolisms?
Pulmonary Embolism Rule-Out Criteria (PERC)
Wells Score
D-Dimer Blood Test
Arterial Blood Gases (ABGs)
ECG Scans
Chest X-Rays (CXRs)
CT Pulmonary Angiogram (CTPA)
Ventilation Perfusion (V/Q) Scans
How is the pulmonary embolism rule-out criteria (PERC) used to investigate pulmonary embolisms?
It is used to exclude pulmonary embolism in cases of low clinical suspicion < 15%
What pulmonary embolism rule-out criteria (PERC) result excludes a pulmonary embolism diagnosis?
When all of the criteria are absent, reducing the probability to < 2%
What are the seven pulmonary embolism rule-out criteria (PERC)?
- Age > 50 Years Old
- Heart Rate > 100bpm
- Previous Pulmonary Embolism/Deep Vein Thrombosis
- Recent Surgery/Trauma In 4 Weeks
- Haemoptysis
- Unilateral Leg Swelling
- Oestrogen Administration
When is the ‘Wells Score’ used to investigate pulmonary embolisms?
It is the first line investigation when the clinical suspicion of pulmonary embolism > 15%
How is the ‘Wells Score’ used to investigate pulmonary embolisms?
It is used to predict the risk of pulmonary embolism in suspected cases
What are the seven criteria of the ‘Wells Score’?
- Deep Vein Thrombosis Features = Calf Swelling, Calf Pain With Deep Vein Palpation (3 Points)
- An Alternative Diagnosis Is At Least As Likely As Pulmonary Embolism (3 Points)
- Heart Rate > 100bpm (1.5 Points)
- Immobilisation > 3 Days Or Surgery In Past 4 Weeks (1.5 Points)
- Previous Deep Vein Thrombosis/Pulmonary Embolism (1.5 Points)
- Haemoptysis (1 Point)
- Malignancy = On Treatment, < 6 Months, Palliative (1 Point)
What does a ‘Wells Score’ of > 4 indicate?
It indicates that a diagnosis of pulmonary embolism is likely
What should be conducted when a ‘Wells Score’ > 4?
Computed tomography pulmonary angiogram (CTPA) should be conducted immediately
What should be conducted when the computed tomography pulmonary angiogram (CTPA) results are positive for pulmonary embolism - Wells Score > 4?
No further investigations are required, a diagnosis is obtained
What should be conducted when the computed tomography pulmonary angiogram (CTPA) results are negative for pulmonary embolism - Wells Score > 4?
A proximal leg vein ultrasound scan should be conducted if deep vein thrombosis is suspected
What should be conducted when the computed tomography pulmonary angiogram (CTPA) cannot be conducted immediately - Wells Score > 4?
An interim therapeutic direct oral anticoagulation (DOAC) should be administered, whilst waiting
What does a ‘Wells Score’ < 4 indicate?
It indicates that a diagnosis of pulmonary embolism is unlikely
What should be conducted when a ‘Wells Score’ < 4?
D-Dimer blood tests should be conducted
What should be conducted when D-Dimer blood test results are positive - Wells Score < 4?
Immediate computed tomography pulmonary angiogram (CTPA) should be conducted
What should be conducted when D-Dimer blood test results are positive and CTPA cannot be conducted immediately - Wells Score < 4?
An interim therapeutic direct oral anticoagulation (DOAC) should be administered, whilst waiting
What should be conducted when D-Dimer blood test results are negative - Wells Score < 4?
The anticoagulation should be stopped, and an alternative diagnosis should be considered
When are D-Dimer blood tests used to investigate pulmonary embolisms?
They are used to exclude a diagnosis of pulmonary embolism when there is low clinical suspicion
However, due to the fact that it can be elevated in other conditions, it cannot provide a definitive diagnosis
What D-Dimer blood test result indicates pulmonary embolisms?
> 0.5 ug/mL
What arterial blood gas (ABG) result indicates pulmonary embolisms? Explain
Respiratory alkalosis
This is due to hyperventilation, resulting in a drop in arterial carbon dioxide partial pressure and thus alkalosis
What are the six features of pulmonary embolisms on ECG scans?
Sinus Tachycardia
Large S Wave In Lead I
Large Q Wave In Lead III
Inverted T Wave In Lead III
Right Bundle Branch Block
Right Axis Deviation
What is the most common ECG feature of pulmonary embolisms?
Sinus Tachycardia
How do we remember the ECG features of pulmonary embolisms?
S1Q3T3
When are chest x-rays (CXRs) used to investigate pulmonary embolisms?
They are used to investigate all pulmonary embolism cases, in order to exclude other pathology
What is the feature of pulmonary embolisms on chest x-rays?
Wedge shaped opacification
What is important to note about the use of chest x-rays when investigating pulmonary embolisms?
In most cases, pulmonary embolisms result in the presentation of a normal chest x-ray scan
When are CT pulmonary angiograms used to diagnose pulmonary embolisms?
They are the first line imaging investigation in suspected non-massive pulmonary embolisms
What are CT pulmonary angiograms?
A CT scan of the chest, with an intravenous contrast, in order to investigate the pulmonary arteries
What is the feature of pulmonary embolisms on CT pulmonary angiograms?
Large saddle embolus within the pulmonary arteries
When are ventilation perfusion (V/Q) scans used to diagnose pulmonary embolisms?
They are the first line investigation in those with renal impairment – in which CT pulmonary angiograms are contraindicated
They are the second line imaging investigation, used when appropriate facilities exist, chest x-ray results are normal and when there is no significant symptomatic concurrent cardiopulmonary disease
What are ventilation perfusion (V/Q) scans?
It involves a nuclear medicine scan which examines air and blood flow in the lungs
The first scan measures how well air flows through the lungs – ventilation
The second scan measures how well blood flows through the lungs -perfusion
The scan images are then compared
What is the feature of pulmonary embolisms on ventilation perfusion (V/Q) scans? Explain
Reduced lung perfusion
This is due to the thrombus blocking blood flow to the lung tissue
What is a contraindication of ventilation perfusion (V/Q) scans?
COPD
What is the TCLO blood test result in pulmonary embolisms?
Decreased TCLO Levels
What are the three pharmacological management options of pulmonary embolisms?
Direct Oral Anticoagulants (DOACs)
Low Molecular Weight Heparin (LMWH)
Vitamin K Antagonists (VKAs)
When are direct oral anticoagulants (DOACs) used to manage pulmonary embolisms?
They are the first line management option of pulmonary embolism, which should be offered once a diagnosis is suspected and continued when the diagnosis is confirmed
What are the two first line direct anticoagulants used to manage pulmonary embolisms?
Apixaban
Rivaroxaban
What are the two second line direct anticoagulants used to manage pulmonary embolisms? When are they used?
Dabigatran
Edoxaban
They are administered following low molecular weight heparin administration
When is low molecular weight heparin (LMWH) used to manage pulmonary embolisms?
It is the second line management option of pulmonary embolism
Name three low molecular weight heparins used to manage pulmonary embolisms
Dalteparin
Enoxaparin
Tinzaparin
Describe the course of low molecular weight heparin used to manage pulmonary embolisms
They should be administered for a 5 – 10 days, followed by direct oral anticoagulants OR vitamin K antagonists for a period of 3 – 6 months
When are vitamin K antagonists (VKAs) used to manage pulmonary embolisms?
They are the second line management option of pulmonary embolism – which are administered following low molecular weight heparin administration
Name a vitamin K antagonist used to manage pulmonary embolisms
Warfarin
What is the pharmacological management option of pulmonary embolisms in active cancer patients?
Direct Oral Anticoagulants (DOACs) - unless contraindicated
What are the three pharmacological management options of pulmonary embolisms in severe renal impairment eGFR < 15?
Low Molecular Weight Heparin
Unfractioned Heparin
Low Molecular Weight Heparin Followed By Vitamin K Antagonist
What is the pharmacological management option of pulmonary embolisms in antiphospholipid syndrome patients?
Low Molecular Weight Heparin Followed By Vitamin K Antagonist
What are provoked pulmonary embolisms?
It is a pulmonary embolism is due to an obvious precipitating event
How long is anticoagulant course treatment in provoked pulmonary embolisms?
3 Months
In which circumstance is provoked deep vein thrombosis treated with an anticoagulation treatment course of 6 months?
Active Cancer
What are unprovoked pulmonary embolisms?
It is a pulmonary embolism not due to an obvious precipitating event
How long is anticoagulant course treatment in unprovoked pulmonary embolisms?
6 Months
How do we determine whether pulmonary embolisms can be managed in an outpatient setting?
Pulmonary Embolism Severity Index (PESI) score
The key requirements include haemodynamic stability, lack of comorbidities and support at home
What are the two surgical management options of pulmonary embolisms?
Thrombolysis
Inferior Vena Cava (IVC) Filters
When is thrombolysis used to manage pulmonary embolisms?
It is the first line management of pulmonary embolism, in which there is circulatory failure – usually indicated by hypotension
What is thrombolysis?
It involves the administration of medications into the circulatory system in order to break up clots and prevent new clots forming
Name three thrombolytic drugs used to manage pulmonary embolisms
Streptokinase
Altepase
Tenecteplase
When are inferior vena cava (IVC) filters used to manage pulmonary embolisms?
They are used to manage recurrent pulmonary embolisms, despite adequate pharmacological management
What are inferior vena cava (IVC) filters?
It involves insertion of a device into the inferior vena cava to stop clots formed in the deep veins of the leg from moving to the pulmonary arteries
What is a high risk factor of pulmonary embolisms in pregnant patient?
Previous history of pulmonary embolism
What prophylactic management should be administered in pregnant patients with high risk factors for pulmonary embolism?
Low molecular weight heparin should be administered throughout the antenatal period, alongside expert input
What are the four intermediate risk factors of pulmonary embolism in pregnant patients?
- Recent Hospitalisation
- Recent Surgery
- Co-Morbidities
- High Risk Thrombophilia
What prophylactic management should be administered in pregnant patients with intermediate risk factors for pulmonary embolism?
Low molecular weight heparin should be considered throughout the antenatal period, alongside expert input
What are the eleven low risk factors of pulmonary embolism in pregnant patients?
- Age > 35 Years Old
- Pulmonary Embolism Family History
- Parity > 3
- Multiple Pregnancy
- In Vitro Fertilisation Pregnancy
- Immobility
- Low Risk Thrombophilia
- Gross Varicose Veins
- Pre-Eclampsia
- Body Mass Index > 30
- Smoker
What prophylactic management should be administered when individuals have three low risk factors of pulmonary embolism?
Low molecular weight heparin should be administered from 28 weeks’ gestation and continued until 6 weeks postnatal
What prophylactic management should be administered when individuals have more than four low risk factors of pulmonary embolism?
Immediate management with low molecular weight heparin should be administered until 6 weeks postnatal
Which two pharmacological management options of pulmonary embolisms are contraindicated in pregnancy?
Direct Oral Anticoagulants
Warfarin
When is prophylactic management of pulmonary embolism administered in hospitalised patients?
When the pulmonary embolism risk is deemed greater than the bleeding risk – determined on an individual case basis
What is the prophylactic management option of pulmonary embolisms in medical hospitalised patients?
Pharmacological anticoagulation, such as fondaparinux, low molecular weight heparin or unfractioned heparin should be administered
What is the prophylactic management option of pulmonary embolisms in surgical hospitalised patients?
The anti-embolism stockings are the first line management option
However, when deemed at high risk pharmacological management should be additionally administered
The post-surgical pharmacological prophylaxis administered is dependent upon the surgical procedure
