Diagnosis of external ventricular catheter-associated infections

External ventricular drains are used to temporarily divert cerebrospinal fluid (CSF) from an obstructed ventricular system. External catheter-associated bacterial infection is a common complication in patients with ventricular drains. Diagnosing ventricular catheter-associated infection can be difficult because of the primary neurological condition of the patient and the occurrence of an inflammatory response in the CSF without infection.
In this thesis we described the diagnostic accuracy of different tests for diagnosing external catheter-associated infection, identified the current diagnostic dilemmas and knowledge gaps and identified new, potentially sensitive and fast biomarkers for diagnosing CSF catheter-associated infection.
We demonstrated that no single CSF, blood or microbiological measure can be used on its own to differentiate between an infection or sterile inflammation. CSF leukocyte count, percentage of polymorphonuclear cells and positive culture results are the most reliable parameters. A positive Gram stain is highly indicative for drain-associated infections but false negative results frequently occur. There is no incremental value of determining CSF and CSF to blood ratios of procalcitonin and lactate for diagnosing CSF catheter-associated infection.
We demonstrated that there is no additional value of daily sampling for diagnosing catheter-associated infection and since it increases the risk of infection, daily sampling should not be performed.
By daily sampling we obtained a time line which gave us an understanding on the progression of the researched parameters over time. CSF first showed signs of bacterial invasion prior to the occurrence of an infectious response. This observation can be a starting point for future research on earlier sensitive detection of catheter-associated infection.