Overview
Introduction
Virchow's Triad Three factors promote venous clot formation.
## Virchow's Triad Three factors promote venous clot formation. | Factor | Meaning | Examples | | --- | --- | --- | | Venous stasis | Blood flow slows | immobility, bed rest, paralysis, prolonged travel | | Endothelial injury | Blood-vessel injury activates clotting | surgery, trauma, vascular injury | | Hypercoagulability | Blood clots more easily than normal | malignancy, pregnancy/postpartum state, oestrogen exposure, thrombophilia | Remember: # STASIS + INJURY + HYPERCOAGULABILITY A patient may have more than one risk factor. For example: surgery + immobility + malignancy creates much greater VTE concern than one isolated factor. ## From DVT to PE A venous thrombus may form in the deep veins. If a portion detaches, it travels: deep vein → vena cava → right atrium → right ventricle → pulmonary artery The clot eventually becomes lodged in a pulmonary vessel. The affected area of lung continues to receive air but receives reduced blood flow. This interferes with normal gas exchange. ## What Happens in the Lungs? PE reduces blood flow through part of the pulmonary circulation....