Traumatic brain injury is a leading cause of death and disability in young people. In an attempt to direct therapy, intracranial pressure (ICP) monitoring and calculated cerebral perfusion pressure (CPP) have been used to make bedside management decisions. However, several studies have shown that cerebral infarction can occur even with normal ICP and CPP.

Given this information, brain tissue oxygen monitoring has been investigated to give an earlier marker of brain ischemia. One new technology has been the use of a Clark-type catheter to measure partial oxygenation of brain tissue (Pb_O2). These probes can be placed in the brain cortex during craniotomy or in the intensive care unit (ICU) by placing a burr hole. There are differing opinions as to whether the probe should be placed in healthy brain tissue or the penumbra of injury.