1. Standardized CSF Drainage Protocols

Controlled CSF diversion via an external ventricular drain (EVD) maintains intracranial pressure (ICP) within target ranges to prevent cerebral edema, herniation, and secondary injury.

Physiological Rationale for ICP Control

• Removal of CSF reduces ventricular volume and ICP when autoregulation is impaired.
• Target adult ICP <20 mmHg (adjust for age or disease).
• In hyperammonemic or metabolic encephalopathies, early CSF diversion mitigates rapid cerebral edema.

Pressure Transducer Setup

1. Level at the external auditory meatus (tragus = foramen of Monro reference).
2. Zero to atmospheric pressure before patient connection.
3. Re‐level and re‐zero after patient repositioning or bed adjustment.

Continuous vs Intermittent Drainage

• Continuous: EVD open at preset ICP threshold; steady control but risk of overdrainage.
• Intermittent: Open only when ICP exceeds threshold; lower overdrainage risk but requires frequent checks.
• Institutional choice guided by patient stability and resource availability.

Preset Pressure and Volume Limits

• Common ICP thresholds: 10–20 mmHg.
• Adult volume limit: ≤20 mL/hour; pediatric limits lower.
• Monitor hourly CSF output to avoid subdural collections or ventricular collapse.

Documentation Practices

• Use standardized order sets and flow sheets.
• Record: reference level, drain setting, hourly output, ICP trends, interventions.
• Checklist for shift changes and rounding.

2. Infection Control Measures

Rigorous aseptic technique at insertion and during maintenance is critical to minimize EVD‐associated infections.

Aseptic Insertion (Maximal Barrier Precautions)

• Full sterile drape, gown, gloves, mask, cap.
• Pre-procedural skin prep: chlorhexidine if tolerated.
• Consider single‐dose prophylactic antibiotic (e.g., cefazolin) per institutional protocol.*

Editor’s Note: Specific prophylactic antibiotic regimen, timing, and dosing vary by institution.

Sterile Handling and Dressings

• Disinfect all access ports with chlorhexidine‐alcohol before CSF sampling or flushing.
• Change dressings every 48–72 hours or when soiled under sterile conditions.
• Limit system breaks and minimize port entries.

Catheter Replacement Criteria

• Do not exchange routinely; increases hemorrhage risk.
• Replace only for confirmed infection or persistent obstruction unresponsive to conservative measures.

Catheter Material Selection

• Standard vs antibiotic-impregnated catheters (AICs).
• AICs elute rifampin/clindamycin to inhibit colonization; consider in high‐risk settings.
• Monitor for cost and potential antibiotic resistance.

Surveillance for Early Detection

• Daily assessment: fever, neck stiffness, altered mental status.
• Routine CSF studies: cell count, glucose, protein, Gram stain; interpret trends.
• Avoid routine cultures in absence of clinical suspicion to limit false positives.

3. Early Recognition of EVD Malfunction and Infection

Timely identification of device malfunction or infection prevents secondary injury and guides urgent interventions.

Clinical Signs

• New fever, meningismus, unexplained agitation or decline in Glasgow Coma Scale.
• Headache or new focal deficits (if patient responsive).

CSF Monitoring

• Inspect appearance: cloudiness, xanthochromia.
• Track CSF WBC trends, glucose drop, protein rise.
• Initiate Gram stain and culture if infection is suspected.

Radiographic Assessment

• Noncontrast head CT to confirm catheter tip location and exclude hemorrhage or ventricular collapse.
• Evaluate for new intraventricular or parenchymal bleed.

Troubleshooting Obstruction

• Blood clot or debris common cause.
• Gentle saline flush if permitted; avoid high‐pressure injections.
• Thrombolytics (e.g., urokinase) controversial—check local protocols.

Initial Interventions

• If infection suspected: remove/exchange catheter under sterile conditions, obtain CSF cultures.
• Start empiric broad‐spectrum antibiotics covering skin flora and Gram‐negatives (e.g., vancomycin + cefepime).*
• Consult infectious disease for targeted therapy and intraventricular antibiotic dosing.

Editor’s Note: Empiric antibiotic choices and intrathecal dosing guidelines are institution‐specific and should be detailed in local protocols.

4. Multidisciplinary Care Coordination

Effective EVD management hinges on structured collaboration among neurosurgery, nursing, and pharmacy.

Roles and Responsibilities

• Neurosurgery: device insertion, troubleshooting, surgical revisions.
• Nursing: transducer checks, drain maintenance, hourly output documentation.
• Pharmacy: order verification, antibiotic selection/dosing, compatibility review (intraventricular agents), antimicrobial stewardship.

Communication Tools

• Use handoff checklists that include EVD settings, recent outputs, complications.
• Conduct daily interdisciplinary rounds with standardized EVD status report.

Pharmacist Contributions

• Review EVD order sets for accurate pressure/volume limits.
• Ensure preservative-free formulations for intraventricular antibiotics.
• Educate staff on drug–device interactions and safe flushing techniques.

Family and Clinician Education

• Provide written and verbal guidance on signs of malfunction/infection.
• Use simulation or bedside demos to reinforce sterile handling basics.

5. Weaning and EVD Removal Criteria

Structured weaning protocols and vigilant post‐removal monitoring minimize the risk of rebound intracranial hypertension.

Assessment of Readiness

• Stable ICP <15 mmHg for ≥24 hours.
• Neurologic exam at baseline or improving.
• Radiographic evidence of ventricular size stability.

Weaning Protocols

• Gradual elevation: raise drain level by 5 cm H₂O every 12–24 hours.
• Clamp trials: close drain and monitor ICP; resume diversion if ICP >20 mmHg or clinical decline.

Decision Algorithms

• Tolerates wean → remove EVD.
• Recurrent elevated ICP → consider permanent shunt or prolonged EVD.

Post‐Removal Monitoring

• Hourly neurologic checks for 12 hours, then every 2–4 hours.
• Repeat head CT if new neurologic changes or persistent headache.
• Reinstate drainage if ICP rises above threshold or exam worsens.