An Overview of  Critical Care

(Traumatic) Brain Injury

The cranial vault contains blood, brain and cerebrospinal fluid (CSF). Any injury that increases the volume of any of these, increases the pressure within the cranium, and causes brain tissue to be squashed. This is called raised intracranial pressure.

Raised Intracranial Pressure

The purpose of virtually all of neurological critical care is to control intracranial pressure (43). The most effective method of doing this acutely is to reduce brain water content, by administering a diuretic (mannitol). The previous use of hyperventilation to cause vasoconstriction is considered a more likely cause of ischemia than salvation. Prolonged cerebral edema is treated by insertion of an intraventicular drainage device, a ventriculostomy, which drains CSF automatically above a set ICP level (e.g. 20cmH₂O). The brain is protected by maintaining oxygen delivery and reducting demand. Brain metabolic activity is reduced, as thus is oxygen and glucose utilization, by appropriate usage of sedative agents – propofol or barbiturates. Seizure prophylaxis, with phenytoin, is often given to avoid unexpected increases in cerebral metabolic demand. Oxygen delivery is ensured by maintaining cerebral perfusion pressure, particularly if there is a considerable amount of cerebral edema. Occasionally, the perfusion pressure is driven upwards by using pressor therapy.

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