Objectives: To evaluate the effect of prolonged infusion of 3% hypertonic saline (514 mEq/L) and sustained hypernatremia on refractory intracranial hypertension in pediatric traumatic brain injury patients.
Design: A prospective study.
Setting: A 24-bed Pediatric Intensive Care Unit (Level III) at Children's Hospital.
Patients: We present ten children with increased intracranial pressure (ICP) resistant to conventional therapy (head elevation at 30 degrees, normothermia, sedation, paralysis and analgesia, osmolar therapy with mannitol, loop diuretic, external ventricular drainage in five patients), controlled hyperventilation (Pco2, 28-35 mm Hg), and barbiturate coma. We continuously monitored ICP, cerebral perfusion pressure (CPP), mean arterial pressure, central venous pressure, serum sodium concentrations, serum osmolarity, and serum creatinine.
Interventions: A continuous infusion of 3% saline on a sliding scale was used to achieve a target serum sodium level that would maintain ICP <20 mm Hg once the conventional therapy and barbiturate coma as outlined above failed to control intracranial hypertension.
Measurements and main results: The mean duration of treatment with 3% saline was 7.6 days (range, 4-18 days). The mean highest serum sodium was 170.7 mEq/L (range, 157-187 mEq/L). The mean highest serum osmolarity was 364.8 mosm/L (range, 330-431 mosm/L). The mean highest serum creatinine was 1.31 mg/dL (range, 0.4-5.0 mg/dL). There was a steady increase in serum sodium versus time zero that reached statistical significance at 24, 48, and 72 hrs (p < .01). There was a statistically significant decrease in ICP spike frequency at 6, 12, 24, 48, and 72 hrs (p < .01). There was a statistically significant increase in CPP versus time zero at 6, 12, 24, 48, and 72 hrs (p < .01). There was a statistically significant increase in serum osmolarity versus time zero at 12 hrs (p < .05) and at 24, 48, and 72 hrs (p < .01). Two patients developed acute renal failure and required continuous veno-venous hemodialysis; these were concurrent with an episode of sepsis and multisystem organ dysfunction. Both recovered full renal function with no electrolyte abnormalities at the time of discharge.
Conclusion: An increase in serum sodium concentration significantly decreases ICP and increases CPP. Hypertonic saline is an effective agent to increase serum sodium concentrations. Sustained hypernatremia and hyperosmolarity are safely tolerated in pediatric patients with traumatic brain injury. Controlled trials are needed before recommendation of widespread use.