Hypertonic saline more efficacious than mannitol in lethal intracranial hypertension model.

Background: Medical management of brain edema and elevated intracranial pressure (ICP) is a crucial challenge in neurosurgical practice. Depending on the cause, the treatments for brain edema fall into three categories: stabilization of the blood-brain barrier, depletion of brain water and surgical decompression. Although mannitol is the mainstay of hyperosmolar therapy, hypertonic saline (HS) is emerging as an effective alternative to traditional osmotic agents.

Methods: Experimental elevated ICP (50 mmHg) was induced in rabbits using an intracranial balloon. The effects of mannitol and HS (10% NaCl) were compared in this specific physiopathological model. Twelve animals were divided into three groups (control, HS and mannitol) according to intravenous administration of 0.9% NaCl, 10% NaCl or 20% mannitol 5 minutes after the elevation of ICP. The doses of 10% NaCl and 20% mannitol were iso-osmolar. During 90 minutes, continuous recording of ICP, mean arterial pressure (MAP) and cerebral perfusion pressure (CPP) was realized.

Results: The control group had a median survival of only 53 minutes, significantly lower than the treated groups (p=0.0002). There was statistical difference between mannitol and HS; the 10% NaCl group had lower values of ICP (p=0.0116) and higher values of MAP (p<0.0001) and CPP (p<0.0001).

Conclusion: The findings demonstrate higher efficacy of the 10% NaCl treatment in this comparison with 20% mannitol. Further efforts should be directed toward development of clinical studies using iso-osmotic doses of mannitol and HS in specific etiologies of intracranial hypertension.