Site of Fluid Loss

Mechanism of Loss

Skin

Thermal or chemical burn, sweating from excessive heat exposure

GI tract

Vomiting or diarrhea

Kidneys

Diabetes mellitus or insipidus, adrenal insufficiency, “salt-losing” nephritis, the polyuric phase after acute tubular damage, and use of potent diuretics

Intravascular fluid lost to the extravascular space

Increased capillary permeability secondary to inflammation or traumatic injury (eg, crush), anoxia, cardiac arrest, sepsis, bowel ischemia, acute pancreatitis