Management of Hypernatremia in Acute Intracranial Hemorrhage

Introduction to Hypernatremia Management

Prolonged therapeutic hypernatremia is not recommended for ICP control in intracranial hemorrhage patients, as the theoretical benefit requires an intact blood-brain barrier to create an osmotic gradient, but hypertonic saline perfusion can be deleterious with disrupted blood-brain barrier by increasing the size of cerebral contusions 1, 2, 3, 4
The relationship between serum sodium and ICP is weak, and hypernatremia is associated with hyperchloremia which may be deleterious for renal function 1
Rapid brain cell volume regulation limits the effectiveness of prolonged hyperosmolarity through synthesis of intracellular osmoles to restore normal cell volume, creating risk of "rebound" ICP during hypernatremia correction 1, 2

Avoid isotonic fluids in patients with renal concentrating defects, as these can worsen hypernatremia 5
The American Heart Association recommends avoiding fluid restriction and maintaining euvolemia in subarachnoid hemorrhage patients at risk of vasospasm 6, 5

Monitor serum sodium every 2-4 hours during active correction, as close monitoring of serum sodium and osmolarity in acute head injured patients is critical, as alterations of these parameters represent substantial risk for cerebral edema 5
The Neurocritical Care Society recommends that correction rates faster than 48-72 hours for severe hypernatremia should be avoided, as they have been associated with increased risk of pontine myelinolysis, and even mild fluctuations in serum sodium can cause neurological deterioration and evidence of early herniation 6

In subarachnoid hemorrhage specifically, hyponatremia (not hypernatremia) is the more common concern, occurring in 10-30% of patients, and hypertonic saline increases regional cerebral blood flow, brain tissue oxygen, and pH in high-grade subarachnoid hemorrhage, but this benefit applies to bolus dosing for acute ICP crises, not sustained hypernatremia 6
The American Academy of Neurology recommends that the strategy of vigilant avoidance of hyponatremia is safer and potentially more efficacious than inducing hypernatremia in intracranial hemorrhage patients 6, 5