Abstract:

ypertonic saline (HS) has been applied in several medical areas, from pneumology, like asthma, cystic fibrosis and bronchiolytis; endocrinology, like hyponatremia and especially in emergency medicine, being applied in traumatic and inflammatory/infectious disorders. They may be composed of 3% or 7.5% sodium chlorate, and differ in accordance to osmolarity. By far, 3% solution is the most widely studied and used solution.
Head injury is the main cause of trauma-related deaths in over 60% of cases. Hemorrhage and shock are observed in up to 20% of patients with head injuries. Hypotension, even for very brief periods, is a well-established cause of secondary brain injury, and contributes to worse outcomes. 
After the initial trauma, a second phase of brain injury begins. Secondary brain injury results from a complex sequence of events that begins just after the initial insult and continues through the acute hospitalization. Secondary brain injury results from a diverse host of etiologies, including edema, ischemia, excitotoxicity, and inflammation. Excitotoxicity occurs when a neuron is destructively stimulated with excess amounts of neurotransmitter, especially glutamate. Inflammation is increasingly recognized to be an important source of secondary brain injury. Additionally, trauma results in a dysregulation of the immune system, predisposing patients to nosocomial infections and worse outcomes. Several studies have pointed that HS is able to improve cerebral and systemic hemodynamic parameters after trauma, with lower volume infusion. HS treatment enhances cell-mediated immune responses in vivo, and elicits immunomodulatory effects that decrease the risk of posttraumatic sepsis. Several experimental and clinical data supports the use of HS not only for volemic resuscitation but to address inflammatory and immune impairments during acute phase.