External ventricular drain

External Ventricular Drain (EVD) is a medical device used in neurosurgery to treat hydrocephalus and to provide temporary drainage of cerebrospinal fluid (CSF) from the ventricles of the brain to an external collection system. This procedure is critical in managing elevated intracranial pressure (ICP) that can result from various brain injuries, infections, or hemorrhages. The placement of an EVD is a delicate process that requires precise surgical technique.

Indications

EVDs are primarily indicated in the management of acute hydrocephalus or elevated ICP due to conditions such as:

• Subarachnoid hemorrhage (SAH)
• Intraventricular hemorrhage (IVH)
• Traumatic brain injury (TBI)
• Brain tumors
• Meningitis and other central nervous system infections

Procedure

The insertion of an EVD involves creating a small burr hole in the skull, usually at a predetermined site called Kocher’s point, which is located about 11cm from the nasion and 3cm lateral to the midline. A catheter is then carefully passed through the brain tissue into one of the lateral ventricles. The catheter is connected to an external drainage system that allows for the controlled release of CSF, thereby reducing ICP.

Complications

While EVD placement is a lifesaving procedure, it carries risks and potential complications, including:

• Infection, which can lead to meningitis or ventriculitis
• Hemorrhage or bleeding into the brain
• Catheter misplacement
• Subdural hematoma
• Overdrainage or underdrainage of CSF

Management and Monitoring

Proper management of an EVD is crucial to ensure therapeutic effectiveness and minimize complications. This includes regular monitoring of CSF output, ICP readings, and signs of infection. The duration of EVD placement varies depending on the underlying condition and response to treatment.

Conclusion

The use of an External Ventricular Drain is a critical intervention in the management of conditions leading to increased intracranial pressure. Despite its risks, when properly managed, an EVD can significantly improve patient outcomes in acute settings of brain injury and infection.