Hypernatremia is very common in the ICU. It often develops during ICU admission due to inadequate free water administration. Hypernatremia is not benign, it causes profound thirst, particularly among intubated patients, this may cause misery and agitation (which may be inappropriately treated with sedatives or antipsychotics).

Hypernatremia may cause delirium, thereby increasing the length of ventilation and ICU stay and it should always be corrected promptly. Untreated hypernatremia is a hallmark of low-quality, amateur ICU care.

Hypernatremia usually won’t improve on its own (it requires active management). Even mild hypernatremia (e.g. sodium 146-148 mEq/L) may cause discomfort and shouldn’t be ignored.

The simplest treatment might be desmopressin (DDAVP) 2 micrograms IV q8 hours. This is effective in causing the kidneys to retain free water. Note, however, that if excessive fluid is provided, the patient will develop hyponatremia. Alternative treatment: vasopressin infusion 0.001-0.01 units/minute, titrated until the urine output decreases to a relatively normal rate.

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