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Hydrodynamic properties of extraventricular drainage systems
Marek Czosnyka1, Zofia H Czosnyka, Hugh K Richards
1Academic Neurosurgical Unit, Addenbrooke's Hospital, Cambridge, England. MC141@MEDSCHL.CAM.AC.UK
Neurosurgery
|February 20, 2003
Summary
Certain extraventricular drains (EVDs) can become obstructed by cerebrospinal fluid, potentially causing dangerous intracranial pressure spikes. Careful handling and specific EVD designs are crucial for safe intracranial pressure management.
Area of Science:
- Neurosurgery
- Biomedical Engineering
- Medical Devices
Background:
- Extraventricular drains (EVDs) are critical for managing intracranial pressure (ICP) in patients with cerebrospinal fluid circulation disorders.
- The hydrodynamic properties of EVDs directly influence their effectiveness in controlling ICP.
Purpose of the Study:
- To evaluate the hydrodynamic performance of five commercially available EVDs.
- To identify potential failure modes affecting ICP control quality.
Main Methods:
- Hydrodynamic resistance testing of five EVD models using a computer-controlled infusion pump.
- Assessment under normal conditions and after simulated contamination of drip chamber vents with water or blood-water mixture.
- Investigation of pressure responses to varying flow rates.
Main Results:
- All tested EVDs exhibited low hydrodynamic resistance, suggesting adequate ICP control capability.
- Three of the five EVDs showed significant hydrodynamic obstruction (>150 mm Hg inlet pressure) after vent contamination.
- Obstruction was linked to a specific vent configuration allowing cerebrospinal fluid accumulation near the filter in a horizontal position.
Conclusions:
- Contact between cerebrospinal fluid and EVD drip chamber vents can cause obstruction and severe intracranial hypertension.
- Certain EVD configurations are more susceptible to blockage than others.
- Clinical protocols should emphasize preventing vent contamination to ensure safe EVD function.