DVT and PE Flashcards
(38 cards)
What is pulmonary embolism (PE)?
Answer:
is a condition where a blood clot (thrombus) forms in the pulmonary arteries, usually as a result of a deep vein thrombosis (DVT) that traveled through the venous system and the right side of the heart to the lungs.
What is the term used to describe the presence of both DVT and PE?
Answer: venous thromboembolism (VTE).
Where are the most common veins in which pulmonary embolism can develop?
Answer:
* Inferior vena cava (IVC)
* Internal iliac vein
* External iliac vein
* Femoral vein (which further divides into the deep femoral vein)
* Popliteal vein, which bifurcates into the anterior tibial vein, posterior tibial vein, and peroneal/fibular vein.
What is Virchow’s triad?
Answer: Virchow’s triad refers to the factors or causes that increase the risk of clots forming within blood vessels. It includes:
a. Stasis
b. Hypercoagulable condition
c. Endothelial damage
What is a saddle embolism?
Answer: is a rare type of acute pulmonary embolism (PE) characterized by a visible thrombus located at the bifurcation of the main pulmonary artery.
* It can lead to sudden hemodynamic collapse and death.
What happens to the V/Q ratio during a pulmonary embolism?
Answer: During a pulmonary embolism,
* there is normal ventilation but abnormal perfusion.
* This leads to an increased V/Q ratio (ratio of ventilation to perfusion), typically above 8% or an elevated alveolar-arterial gradient.
* Consequently, there is a significant difference between alveolar oxygen levels and arterial oxygen levels,
* resulting in hypoxemia.
How are patients with high risk factors of PE are managed?
Answer: are typically treated with
low molecular weight heparin, such as enoxaparin, to reduce the risk of pulmonary embolism.
Contraindications for this treatment include active bleeding or existing anticoagulation with warfarin or a NOAC (novel oral anticoagulant).
Anti-embolic compression stockings are also commonly used unless contraindicated.
When are compression stockings or anti-embolic compression stockings not allowed?
Answer: Compression stockings or anti-embolic compression stockings are not allowed in patients with significant peripheral arterial disease.
How does bone embolism lead to pulmonary embolism?
Answer: Bone embolism occurs in cases of long bone fractures.
* Within the center of the medullary cavity, fat is present.
* Fat globules can escape into the pulmonary circulation, leading to a pulmonary embolism.
How do IV drug users develop embolism?
Answer: IV drug users have an increased risk of carrying bacteria, which can lead to infective endocarditis.
* The organisms, such as S. aureus, can enter the bloodstream directly from the skin and tend to stay within the tricuspid valve, forming vegetations.
* These vegetations can break off and travel from the right ventricle to the pulmonary circulation, becoming lodged in the pulmonary artery.
* It is important to avoid high doses of DOACs (direct oral anticoagulants) in IV drug users.
What is pleuritic chest pain?
Answer:
* is a type of chest pain that is caused by inflammation of the pleura, the thin membrane lining the inside of the chest wall and covering the lungs.
* It is characterized by sharp or stabbing chest pain that is typically worsened by breathing or coughing.
* It can be associated with conditions such as pneumonia, pulmonary embolism, pleurisy, rib fractures, lung cancer, pericarditis, or costochondritis.
How does respiratory alkalosis occur during a pulmonary embolism?
Answer:
* due to an increase in respiratory rate, leading to hypocapnia (reduced carbon dioxide levels in the blood).
* The increased respiratory rate enhances the uptake of oxygen and the elimination of carbon dioxide, resulting in a decrease in carbon dioxide levels and an increase in blood pH.
How does hemoptysis (coughing up blood) happen in pulmonary embolism?
Answer:
* when platelets stick together, leading to pulmonary vasoconstriction and inefficient ventilation of a clogged vessel (with a clot).
* This results in the redirection of blood to nearby, effective alveoli, causing stress on the heart and decreased oxygen supply to the lungs.
* Ultimately, this can lead to infarction of the lungs and a ruptured alveolar capillary membrane, causing blood to leak into the airway and result in hemoptysis.
How does hypotension occur in pulmonary embolism?
Answer:
* due to increased resistance that the right ventricle (RV) faces in pumping against the high pressure in the pulmonary system.
* This leads to RV dilation and dysfunction, resulting in decreased (SV) and (CO) into the left atrium (LA).
* This decreases preload in the left ventricle (LV), leading to decreased SV, CO, and ultimately systemic blood pressure.
* The blood backs up into the right atrium (RA) and may cause jugular venous distention.
* Additionally, the interventricular septum may deviate towards the LV lumen, further obstructing LV function and contributing to hypotension.
How does the body compensate for hypotension during a pulmonary embolism?
Answer:
* through the activation of baroreceptors in the carotid and aortic sinuses, which sense changes in blood pressure.
* The baroreceptors send signals via cranial nerves (IX and X) to the medulla, resulting in an increase in sympathetic nervous system (SNS) activity.
* This leads to reflexive tachycardia (increased heart rate), increased contractility of the heart, and vasoconstriction of peripheral vascular resistance (PVR), ultimately aiming to increase blood pressure.
when is CTPA is contradndiacted and what test is used inseted
V/Q scans are particularly useful in patients with
renal impairment,
contrast allergy,
or those at risk from radiation where a CTPA is not suitable such as pregnat woman’s .
Q: What is the most common finding on an ECG in a patient with a pulmonary embolism?
A: **Sinus tachycardia **is the most common finding on an ECG in a patient with a pulmonary embolism.
Q: What is the most common finding on an ECG in a patient with a pulmonary embolism?
A: **Sinus tachycardia **is the most common finding on an ECG in a patient with a pulmonary embolism.
Q: What does a normal chest X-ray (CXR) early on in PE indicate?
A: A normal chest X-ray early on in pulmonary embolism (PE) suggests that infarction has not occurred yet.
CXR is often used to rule out other causes, and a “wedge-shaped infarct” on CXR can indicate PE.
Q: When is an ultrasound scan of the leg (USS leg) used in the evaluation of PE?
- A: is used when radiation needs to be avoided (e.g., during pregnancy) or
- when deep vein thrombosis (DVT) is suspected as a possible cause of the pulmonary embolism.
Q: What is the role of a pulmonary angiogram in diagnosing PE?
A: A pulmonary angiogram is an invasive test and is considered the most definitive diagnostic test for pulmonary embolism.
However, it carries an increased risk due to its invasiveness and is usually reserved for cases where other non-invasive tests have provided inconclusive results or when immediate intervention is required.
Q: What does the S1Q3T3 pattern represent in an ECG?
A: The S1Q3T3 pattern in an ECG represents right heart strain.
It includes deep S wave in lead I,
deep Q wave and inverted T wave in lead III.
It can indicate right ventricular dysfunction, which is often associated with a pulmonary embolism.
: What is the significance of troponin levels in a patient with a pulmonary embolism?
A: Troponin levels may be raised in a patient with a pulmonary embolism due to the **strain on the right ventricle. **
Elevated troponin levels in this context are associated with worse outcomes.
What respiratory changes can be observed in arterial blood gas (ABG) analysis during different stages of PE?
A: In the early stages of PE, ABG may show respiratory alkalosis due to increased respiratory rate and decreased CO2 levels.
However, in later stages, fatigue of respiratory muscles can lead to respiratory acidosis
