J. Sales-Llopis

Neurosurgery Department, General University Hospital of Alicante, Spain

Structured approach to evaluate readiness for external ventricular drain (EVD) removal and minimize risk of hydrocephalus relapse or shunt dependency.

• Resolution of acute condition (e.g., stabilized IVH or ICH)
• Neurologically stable for ≥ 24–48 hours
• Controlled ICP (< 20 mmHg) with minimal or no CSF drainage
• No evidence of active infection or new hydrocephalus on imaging

• Raise drain to +20 cmH₂O above EAM
• Monitor for 24 hours
• If no CSF drainage and patient stable → proceed to next step

• Clamp EVD completely (closed system, monitor ICP)
• Monitor for:
  1. ↑ ICP (> 20–25 mmHg)
  2. ↓ consciousness or new symptoms
  3. New ventricular enlargement on CT

• Duration: 24–72 hours, depending on risk and tolerance
• If tolerated → CT scan → consider EVD removal

• ICP spikes > 25 mmHg (sustained)
• Neurologic deterioration
• New or worsening hydrocephalus on CT
• Symptomatic bradycardia, vomiting, headache

• Unclamp EVD and drain 10–15 mL slowly before removal (optional)
• Remove catheter under sterile conditions
• Apply occlusive dressing and monitor site
• Monitor patient closely for 48–72 h post-removal

• Re-open EVD and reassess need for:
  1. Repeat weaning trial after 48–72 h
  2. Permanent CSF diversion (e.g., ventriculoperitoneal shunt)

• Do not rush clamping in unstable or comatose patients
• Ensure no obstruction before concluding tolerance (a dry EVD can be blocked)
• Always confirm with neuroimaging before final removal

Clinical criteria and decision-making pathway to determine when a patient with an external ventricular drain (EVD) requires permanent CSF diversion via ventriculoperitoneal (VP) shunt.

• Persistent hydrocephalus despite EVD > 7–10 days
• Weaning failure after ≥2 trials (clamping intolerance or ICP crisis)
• Recurrent CSF drainage need (e.g., > 150–200 mL/day to maintain ICP < 20 mmHg)
• New or worsening ventricular enlargement on imaging
• Clinical deterioration when EVD is clamped
• Known obstructive hydrocephalus (e.g., aqueductal stenosis, post-SAH, IVH with cast)
• Recurrent intraventricular hemorrhage, chronic communicating hydrocephalus
• Recovery phase of poor-grade SAH or IVH with persistent CSF resorption failure

• Perform repeat CT scan after EVD clamping trial
• Confirm no CSF infection (send CSF culture, cell count)
• Rule out reversible causes (e.g., meningitis, elevated protein > 150 mg/dL)
• For IVH patients: delay shunting if active blood clearance is ongoing

• Normalize coagulation parameters
• Decide on programmable vs fixed-pressure valve
• Consider endoscopic third ventriculostomy (ETV) as alternative in non-communicating cases
• Confirm no active infection or sepsis
• Discuss shunt dependency risk with patient/family

• Active CSF infection (e.g., ventriculitis)
• Uncontrolled systemic sepsis
• Very high protein or debris in CSF
• Unstable patient not yet optimized for surgery

To safely remove an external ventricular drain (EVD) or convert to a ventriculoperitoneal (VP) shunt, the following microbiological criteria must be met:

• Ideally spaced 24–48 hours apart
• Collected after antibiotic therapy is completed or near completion
• No growth on culture
• Normalizing CSF cell count and protein (↓ WBC, ↓ neutrophils, ↓ protein)

• One negative culture may miss low-level or biofilm infections
• Shunting in presence of infection → ↑ risk of:
  1. Shunt infection
  2. Shunt malfunction
  3. Recurrent ventriculitis or abscess

• Always evaluate CSF glucose, protein, cell count along with culture
• Avoid CSF sampling unless clinically indicated to reduce infection risk