DVT and PE Flashcards
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.
