How should correction of dysnatremia be monitored?
The serum sodium should be monitored every 2 to 4 hours during hypertonic saline infusion. Urine volume should also be closely watched during this period. Patients with hypovolemic or thiazide-induced hyponatremia may experience a spontaneous water diuresis once volume depletion has been corrected, sometimes after only a modest amount of normal saline given for volume repletion. The occurrence of such a water diuresis will put the patient at risk for ODS. In some patients, spontaneous correction is so rapid that the major therapeutic consideration is how to limit the rise in serum sodium concentration. Although initiation of hypertonic saline infusion in patients with severe symptoms should not be delayed until intensive care unit (ICU) transfer, monitoring urine output on an hourly basis and serum sodium concentration every 2 hours is most readily accomplished in the ICU.