Moderate-Severe Traumatic Brain Injury (TBI) Practice Exam

In severe brain injury, you want a system that both tracks what's happening inside the skull and actively reduces pressure by removing CSF. The external ventricular drain does exactly that: a catheter goes into the ventricular system, and the same setup provides continuous ICP readings (via a pressure transducer) while allowing controlled drainage of CSF to lower intracranial pressure. This dual function helps prevent secondary injury from rising ICP and guides treatment.

The other options don’t provide this combination. An intra-arterial pressure monitor measures arterial blood pressure, not intracranial pressure or CSF drainage. A lumbar puncture kit can sample CSF and may give an opening pressure, but it isn’t continuous ICP monitoring and it accesses CSF lower in the spine, not the ventricles. A subdural drain removes fluid from the subdural space and does not access ventricular CSF or provide reliable ICP monitoring.