Cerebral CO2 reactivity in severe head injury. A transcranial Doppler study.

Background: Cerebral circulation is profoundly affected by changes in PaCO2. CO2 manipulation plays a basic role in the management of intracranial hypertension; CO2 reactivity (CO2R) defines the changes in CBF in response to changes in PaCO2. Transcranial Doppler has allowed exploring its effects "on line".