Potassium losses result in muscle weakness and cardiac arrhythmias. If more water is lost than sodium, hypernatremia occurs which may lead to confusion and impaired consciousness. Dehydration produces symptoms and can be expressed as a fraction of total body water deficit. In addition, the mouth and tongue become increasingly dry, and the skin looses its elasticity. With 5 percent or greater fluid loss, the eyes become sunken.
Urine flow begins to decrease as soon as fluid intake lessens or fluid losses increase.
Therefore, measuring the amount of urine flow in 12 or 24 hours is an excellent measure of adequate hydration. The volume can be measured at home and should be at least 1500 ml in a 24 hour period for most adults. Much less than this suggests some degree of dehydration. The fluids lost by an abnormal GI tract depend on the actual disease process, the part of the bowel involved, and how long the bowel has recuperated from the initial insult. The more small intestine that is lost, the more important becomes the fluid absorptive ability of the colon.