How do you determine when to change an EVD in a trauma patient that may not need a shunt?

The keyword here is “change”. I don’t routinely change an EVD based on time. I believe the actuarial data suggest that the major risk of infection is during insertion/replacement, showing up days later due to progression rather than subsequent inoculation. This obviates any indications for routine, scheduled EVD replacement in my practice.

It will be useful to answer the possible shunt issue. My challenge technique is to either raise the drainage level dramatically or clamp it and keep a close eye on the patient for deterioration. That delivers an answer definitive enough to prompt further action. If the patient demonstrates benefit from CSF diversion, then the next step will be a shunt.

If the patient does not appear to need CSF diversion ...