Pathophysiology of Burn

Pathophysiology of Burn

• Local: Within moments the capillaries of the injured tissue become leaky. Plasma is lost, drawing water with it. This continues for between 3 and 36 hours and results in edema of the tissues involved. Local airway swelling may lead to loss of the airway by both internal and external edema. Chest wall edema may make ventilation difficult and edema of the limbs may cause ischemia leading to limb loss (especially if the burn is circumferential). Hypovolemia and hemoconcentration of the blood leads to a rising hematocrit which will result in poor systemic tissue perfusion. Red blood cells are lost both directly in the burn and as a result of increased fragility.
  
• Systemic: Damaged tissue will release substances like prostaglandins, and histamine into the circulation leading to a systemic increase of capillary permeability and hypovolemia.