What are the steps to manage an External Ventricular Drain (EVD) that is not draining?

Management of a Non-Draining External Ventricular Drain

When an EVD stops draining, immediately assess for catheter occlusion (which occurs in 26.4% of cases) and systematically troubleshoot mechanical causes before considering catheter replacement. 1

Initial Assessment and Troubleshooting

Verify System Patency

• Check the entire drainage system for kinks, closed stopcocks, or disconnections that may be preventing flow 1
• Confirm the drainage collection system is positioned at the correct height relative to the external auditory meatus (typically 10-15 cm above for ICP monitoring or at prescribed level for CSF drainage)
• Ensure all connections are secure and the system hasn't been accidentally clamped

Assess Clinical Context

• Patients with casting ventricles have significantly higher occlusion rates (38.8% vs 23.1%) compared to those without casting 1
• Higher intraventricular blood burden (49.2 cc vs 27.2 cc) is strongly associated with catheter occlusion 1
• Evaluate for signs of increased intracranial pressure: altered mental status, headache, vomiting, pupillary changes
• Review recent imaging to assess ventricular size and blood/debris burden

Mechanical Interventions

Catheter Repositioning

• If using a depth-adjustable fixation device, retract the catheter 5-12 mm (mean 8.7 mm) to potentially reopen drainage, which successfully restores flow in 80% of obstructed drains 2
• This technique is particularly useful when ventricular tightening causes the catheter tip to become apposed against ventricular wall 2
• Remove the fixture spring, adjust catheter depth to restore CSF flow, then replace the spring 2

Catheter Flushing Considerations

• Flushing should be performed with extreme caution and only by experienced neurosurgical personnel due to risk of introducing infection or causing hemorrhage
• Consider gentle aspiration before flushing to avoid forcing debris deeper into the ventricle
• Use strict aseptic technique if any manipulation of the system is required 3, 4

When to Replace the Catheter

Indications for Replacement

• Persistent occlusion despite troubleshooting and repositioning attempts 1
• Suspected infection (remove immediately if EVD-related infection is confirmed) 5
• Catheter malposition confirmed on imaging 1
• Duration approaching or exceeding 5 days, as catheters should be removed as soon as clinically possible and preferably before 5 days to reduce infection risk 1

Replacement Strategy

• Place new catheter at a different anatomic site if infection is present 5
• Use antibiotic-coated catheters (clindamycin/rifampin or minocycline/rifampin) rather than uncoated catheters, as they reduce infection risk significantly (OR 0.23,95% CI 0.17-0.32) 1
• Prefer bolted EVDs over tunneled EVDs, as bolted catheters have significantly lower malfunction rates (OR 0.31,95% CI 0.16-0.58) and reduced risk of CSF leakage (3.2% vs 36%) 1
• Consider larger lumen catheters (2.3 mm vs 1.5 mm inner diameter), as small lumen catheters have 5.8 times higher risk of occlusion 1

Special Considerations for Intraventricular Hemorrhage

Adjunctive Fibrinolytic Therapy

• Consider intraventricular fibrinolysis (IVF) for patients with significant IVH burden, as it reduces mortality from 40.9% to 22.4% (OR 0.39,95% CI 0.29-0.54) 1
• IVF significantly reduces catheter occlusion rates and shortens treatment duration 1
• IVF accelerates clot resolution by approximately 3 days (5.9 mL vs 11.5 mL residual volume) 1

Critical Pitfalls to Avoid

• Never discharge a patient with an EVD in place - EVDs are exclusively intrahospital devices requiring continuous ICU monitoring 5
• Do not ignore CSF leakage - handle immediately (within 24 hours) as leakage >1 day increases ventriculitis risk to 21.1% vs 0% with prompt management 1
• Avoid silver-impregnated catheters - they show no significant infection prevention benefit compared to uncoated catheters (OR 0.81,95% CI 0.54-12.2) 1
• Do not maintain EVDs longer than necessary - infection rates increase with duration, and the overall infection rate is 8.3-12.8% 1, 6, 4