Neurosurgery iOS application External Ventricular Drain

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Background An external ventricular drain (EVD) facilitates drainage of cerebrospinal fluid (CSF) from the ventricles to an external reservoir. This procedure is useful for treating acute hydrocephalus secondary to a variety of etiologies, and also provides a means of monitoring intracranial pressure (ICP). An EVD can be rapidly placed at bedside, and is among the initial procedures for which neurosurgery trainees must gain independent proficiency. (1) Acute hydrocephalus is the abnormal buildup of CSF in the ventricles with subsequent dilation of the intraventricular spaces. This can result from subarachnoid hemorrhage, intraventricular hemorrhage, mass lesions, cerebral edema, meningitis, ventriculitis, trauma, or hepatic encephalopathy. Hydrocephalus can be communicating, caused by impaired CSF resorption, or non-communicating, caused by flow obstruction. Symptoms will progressively worsen if untreated; these include headaches, nausea, somnolence, coma, and eventually life threatening elevations in ICP causing herniation. Therefore, it is important to recognize the etiologies and provide timely treatment with an EVD if required. EVDs can also be used for ICP monitoring, notably in cases of severe brain trauma. Current guidelines recommend ICP monitoring for traumatic brain injury in patients with a GCS ≤ 8. (2) Although other devices are often used for this purpose, an EVD has the added benefit of therapeutic CSF drainage. Once placed, an EVD can be used to sample CSF for lab analysis, and in some cases administer intraventricular medication such as antibiotics.