[Prevention of secondary brain injuries]

Neurologic complications after severe brain injuries are the result of primary injuries in the moment of impact and secondary injuries which evolve over the minutes and days later. According to statistics, secondary injuries were documented in about 90 percent of patients who died after traumatic brain injury. Low oxygen delivery in hypotension, hypoxia, oedema, intracranial hypertension or changes in cerebral blood flow all account for development of secondary injuries. Primary injuries are more or less complete, but secondary injuries could be prevented with adequate therapy. Understanding mechanisms of secondary injuries could help identify potentially beneficial therapies. Important elements of therapy are: head position, normoglycemia, osmotherapy, normal body temperature, optimal blood pressure, adequate oxygenation, barbiturate therapy. Neutral head and neck position is recommended to prevent intracranial hypertension. Hyperglycemia with less ATP leads to ishaemic acidosis, hypoglycemia enhances decomposition of phospholipids and release of fat acids, what makes the cellular damage worse. Normocapnia is recommended and adequate oxygenation (PaO2 higher than 90%). To prevent dehydration and electrolyte imbalance, serum electrolytes should be examined every 4-6 h as well as osmolarity. Moderate therapeutic hypothermia could be of benefit, and maintaining of optimal blood pressure (MAP above 90 mmHg), especially in the first period after injury. As these have a lot of adverse effects, barbiturates are recommended only when conventional therapies show no effect. Patients should be hydrated well before induction of barbiturates. In organized trauma centers and with adequate intensive care the mortality from traumatic brain injury decreased from 50% in 1970, to about 30% now days.