Brain edema or cerebral edema is an excess accumulation of water in the intracellular and/or extracellular spaces of 
the brain. It is the main cause of intracranial hypertension in patients with intracranial hemorrhage. In the terms of Osmotic cerebral edema, normally cerebral-spinal fluid and extracellular fluid osmolality of the brain is slightly greater than that of plasma. When plasma is diluted by excessive water intake, syndrome of inappropriate antidiuretic hormone secretion, hemodialysis, or rapid reduction of blood glucose in hyperosmolar hyperglycemic state, formerly hyperosmolar non-ketotic acidosis, the brain osmolality will then exceed the serum osmolality creating an abnormal pressure gradient down which water will flow into the brain causing edema (source: wikipedia.org)
Intracranial hypertension aggravates brain edema by altering cerebral perfusion and cerebral venous blood outflow. Therefore, a correction to Intracranial Pressure (ICP) is an important goals in intensive care. However, information about effects of hyperosmolar solutions on cerebral oxygenation and metabolism is very small, data about hyperosmolar solutions influence on the ICP, systemic hemodynamics and mortality are controversial. The following article published in Bentham Open Critical Medicine Care Journal, estimated the dynamics of cerebral oxygenation and metabolism during intracranial pressure correction with 15% Mannitol and 7,2% saline in 6% HES 200/0,5.
S.S. Petrikov and colleagues from Department of Neurosurgery, Neurosurgical ICU, Department of Ultrasound diagnostics, Sklifosovsky Research Institute, Moscow, Russia analyzed 39 episodes of ICP correction with 15% Mannitol or 7,2% NaCl in 6% HES 200/0,5 (“Hyper-HAES”) in 9 patients with intracranial hemorrhage. Monitoring of ICP, systemic hemodynamics, SvjO2 and cerebral microdialysis was used in all patients. Brain temperature and brain oxygen tension were investigated in 5 patients. ICP > 20 mmHg was the indication for treatment, according to the article.
You can find 10 pages/1.9 Mb detailed read of Intracranial Hypertension Correction with Hyperosmolar Solutions and its Effect to the Brain here in PDF Filetype (source: bentham.org). See another Neurology Journal in this site.
