Cell Index in the Diagnosis of External Ventricular Drain-Related Infections

BACKGROUND: The use of an external ventricular drain is required for the treatment of many diseases, such as traumatic brain injury and subarachnoid hemorrhage (SAH). Meningitis and ventriculitis are frequent complications arising from the use of external ventricular drain therapy. This study aimed to determine the sensitivity, specificity, and cutoff point for cell index (CI) in patients with traumatic brain injury, SAH, and hemorrhagic stroke. METHODS: Our study population consisted of patients with different underlying diseases and few culture-positive cerebrospinal fluid samples. The diagnosis of infection was based on Centers of Disease Control and Prevention criteria. RESULTS: Overall CI analysis showed an area under the curve (AUC) of 0.982. The cutoff of 2.9 for overall CI provided a sensitivity of 95% and a specificity of 92.9%. In patients with SAH, the AUC was 1.0 for a CI of 2.8; furthermore, sensitivity and specificity were 100%. The relative variation of the CI was also assessed. This analysis revealed an AUC of 0.882, and a 4.33-fold increase was found be indicative of infection (P = 0.002), findings similar to those in the literature. In addition, a heatmap analysis demonstrated that the CI is unlikely to return to normal in patients with meningitis, even after treatment. CONCLUSIONS: Therefore, CI is valuable for the diagnosis of infection, but was inadequate for monitoring treatment. We hope to use the new cutoff point proposed by this study in our institution to improve patient clinical outcome.