## Virchow's Triad Three major factors promote venous clot formation. | Factor | Meaning | Examples | | --- | --- | --- | | Venous stasis | Blood flow slows | immobility, bed rest, paralysis, prolonged travel | | Endothelial injury | Vessel-wall injury activates clotting | surgery, trauma, vascular injury | | Hypercoagulability | Blood has an increased tendency to clot | cancer, pregnancy/postpartum state, estrogen exposure, thrombophilia | Remember: # STASIS + ENDOTHELIAL INJURY + HYPERCOAGULABILITY A client may have several factors at the same time. For example: major surgery + reduced mobility + malignancy creates a higher VTE risk than one isolated factor. ## From DVT to PE A thrombus may form in a deep vein. If part of it detaches, it travels: deep vein → vena cava → right atrium → right ventricle → pulmonary artery The embolus becomes lodged in the pulmonary arterial circulation. Blood flow beyond the obstruction decreases. ## What Happens in the Lungs? The affected area of lung may continue to receive ventilation while receiving inadequate blood flow. This produces ventilation-perfusion...