Hypovolemic hypernatremia

Hypovolemic hypernatremia (loss of water and sodium [water > sodium])... 

Treatment of hypovolemic hypernatremia should begin with 0.9% saline. After hemodynamic stability is restored and intravascular volume is replaced, free-water deficit can be replaced with 5% dextrose or 0.45% saline solution. 

Hypovolemic hypernatremia (postural hypotension, tachycardia, and decreased skin turgor) should initially be treated with 0.9% saline until hemodynamic stability is restored. An initial infusion rate of 200 to 300 mL/h will likely be appropriate for many patients. Once intravascular volume is restored, 0.45% saline or 5% dextrose in water (D5W) can then be infused to correct the water deficit, the volume of which may be estimated as ... 

Treatment of hypernatremia. Treatment depends on the cause, but in most cases, the patient is hypovolemic and needs fluids. Caution Do not reduce the serum sodium level too quickly, because osmotic imbalance may cause excessive fluid shift into brain cells, resulting in cerebral edema. The correction should take place over 24-36 hours the serum sodium should be lowered about 1 mEq/L/h. 

Laboratory testing (such as osmolality) is important to help distinguish between hypervolemic or hypovolemic hyponatremia or hypernatremia. 

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