Volume and electrolyte management.
Osmolality is the primary determinant of water movement across the intact blood-brain barrier (BBB), and we can predict that reducing serum osmolality would increase cerebral oedema and intracranial pressure. Brain injury affects the integrity of the BBB to varying degrees. With a complete breakdown of the BBB, there will be no osmotic/oncotic gradient, and water accumulates (brain oedema) consequentially to the pathological process. In regions with very moderate BBB injury, the oncotic gradient may be effective. Finally, osmotherapy is effective in brain areas with normal BBB; hypertonic solutions (mannitol, hypertonic saline) dehydrate normal brain tissue, with a decrease in cerebral volume and intracranial pressure. In patients with brain pathology, volume depletion and/or hypotension greatly increase morbidity and mortality. In addition to management of intravascular volume, fluid therapy must often be modified for water and electrolyte (mainly sodium) disturbances. These are common in patients with neurological disease and need to be adequately treated.
Tommasino
Concezione
C
Institute of Anaesthesiology and Intensive Care, University of Milano, Department of Anaesthesia, San Paolo University Hospital, Via di Rudini 8, 20142 Milano, Italy. concezione.tommasino@unimi.it
Picozzi
Valentina
V
D001812:Blood-Brain Barrier; D001921:Brain / Q000098:blood supply / Q000503:physiopathology; D001929:Brain Edema / Q000209:etiology / Q000503:physiopathology / Q000517:prevention & control*; D001930:Brain Injuries / Q000150:complications / Q000601:surgery; D002560:Cerebrovascular Circulation; D005440:Fluid Therapy / Q000379:methods*; D006801:Humans; D020896:Hypovolemia / Q000209:etiology / Q000517:prevention & control; D007427:Intracranial Pressure; D019635:Neurosurgical Procedures / Q000009:adverse effects*; D009994:Osmolar Concentration; D011182:Postoperative Care; D015532:Rehydration Solutions / Q000627:therapeutic use; D012462:Saline Solution, Hypertonic / Q000627:therapeutic use; D013345:Subarachnoid Hemorrhage / Q000150:complications / Q000601:surgery; D014882:Water-Electrolyte Balance
D015532:Rehydration Solutions; D012462:Saline Solution, Hypertonic