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A 56-year-old woman with history of hypertension and hyperlipidemia presented with a sudden onset of severe headache followed by nausea and vomiting. She was taken by ambulance to the nearby emergency department (ED). In the ED, the patient was alert and oriented to person, place, and time but was lethargic and uncooperative, without focal neurologic deficit. Noncontrast head computed tomographic (CT) scan demonstrated thick hyperdensity in the sylvian and interhemispheric fissures, as well as in the basilar cisterns. Her third and lateral ventricles were notably dilated. She was diagnosed with subarachnoid hemorrhage (SAH) with evidence of early hydrocephalus, and was urgently transferred to the neurologic intensive care unit (NICU, NeuroICU) for further management.
On arrival to the NICU she was lethargic, mumbling incoherently, not following commands, pupils were symmetrically reactive, and she moved all extremities with good strength. Vital signs: heart rate 88 bpm, respiratory rate 16 breaths/min, temperature 37.4°C (99.4°F), blood pressure 110/60 mm Hg. See Figure 22-1.
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Does this patient need an external ventricular drain (EVD)? What are the indications for EVD placement?
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This patient's presentation is consistent with Hunt and Hess (HH) grade III and Fisher grade 3 SAH (see Chapter 1 for information on SAH grading). Radiographic evidence of acute hydrocephalus along with neurologic decline (failure to follow commands) call for emergent placement of an external ventricular drain (EVD) to alleviate intracranial hypertension. EVDs serve three primary functions in SAH: to monitor intracranial pressure (ICP), to drain cerebrospinal fluid (CSF) for treatment of hydrocephalus, and/or to acutely reduce ICP. EVD placement is therefore indicated when a patient is thought to have symptomatic hydrocephalus and/or elevated ICP, based on neurologic examination and radiographic findings.
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Ventriculostomy is considered standard-of-care for treating SAH-associated hydrocephalus and has been shown to improve both short- and long-term outcomes.1 However, there is no standard, evidence-based guideline for EVD placement in SAH patients. Although the Glasgow Coma Scale (GCS) score (eg, 12 or less)2 and HH grade (eg, III or greater)3 have been used to establish an objective threshold for ventriculostomy, the procedure should be generally considered in patients who demonstrate clinical or radiologic deterioration or have an unreliable neurologic examination. Patients who present comatose or severely lethargic are almost universally considered for emergent ventriculostomy.4 At our institution, all SAH patients not following commands are strong candidates for EVD insertion (Figure 22-2). Minimal improvement in neurologic status despite normalization of the ICP in these patients may point to other etiologies such as seizure, medication effect, or metabolic derangement and prompts immediate investigation. As for those with fluctuating levels of consciousness, the impact of ventriculostomy on outcome remains unclear and, therefore, careful risk-benefit analysis is warranted.2 Figure 22-3 outlines our ICP management protocol for patients admitted to our NICU with aneurysmal SAH ...