Volume supplementation with iso-sodium solution prevents hypernatremia after head injury

OBJECTIVE: To evaluate our developed volume supplement protocol in preventing hypernatremia after head injury. METHODS: Iso-sodium solution was infused to keep the 8-hour water balance positive in 20 head-injured patients with hypotonic urine. RESULTS: Serum sodium concentrations moved to within a normal range in 6 patients and were temporarily increased in 12 patients. Seven of the 12 showed a negative cumulative water balance and slightly low creatinine clearance. Mean arterial pressure in the other five patients was lower after supplementation and was positively related to sodium excretion. Hypernatremia could not be prevented in the other two patients and they did not survive. Creatinine clearance was below 40 mL/min/m2 in these two patients before supplementation. CONCLUSION: Our protocol worked effectively in patients in whom renal function was preserved. Decreased creatinine clearance because of preexisting dehydration and lower arterial pressure disturbed increase in urinary sodium excretion and temporarily aggravated the hypernatremia.