Emily Hill1, Thomas P Bleck2, Kamaljit Singh3, Bichun Ouyang4, Katharina M Busl5. 1. Department of Neurological Sciences, Rush University Medical Center, 1725 West Harrison Street, POB Suite 1121, Chicago, IL, 60612, United States. 2. Neurological Sciences, Neurosurgery, Internal Medicine, and Anesthesiology, Rush Medical College and Director of Clinical Neurophysiology, Rush University Medical Center, 600 S Paulina Street, Chicago, IL 60612, United States. 3. Microbiologist & Infectious Diseases Attending, North Shore University Health System, Evanston, IL, United States. 4. Department of Neurological Sciences, Rush University Medical Center, 1725 West Harrison Street, Chicago, IL 60612, United States. 5. Department of Neurology, Division of Neurocritical Care, University of Florida, United States. Electronic address: katharina.busl@neurology.ufl.edu.
Abstract
INTRODUCTION: In a febrile patient with a ventriculostomy, diagnosing or excluding bacterial or microbial ventriculitis is difficult, as conventional markers in analysis of cerebrospinal fluid (CSF) are not applicable due to presence of blood and inflammation. CSF lactate has been shown to be a useful indicator of bacterial meningitis in CSF obtained via lumbar puncture, but little and heterogenous data exist on patients with ventriculostomies. METHODS: We reviewed all CSF analyses obtained via ventriculostomy in patients admitted to our tertiary medical center between 2008 and 2013, and constructed receiver operating characteristic (ROC) curves to evaluate the accuracy of CSF lactate concentration in discriminating a positive CSF culture from a negative one in setting of ventriculostomy and prophylactic antibiosis. RESULTS: Among 467 CSF lactate values, there were 22 corresponding CSF cultures with bacterial growth. Sensitivities and specificities for CSF lactate at threshold values 3, 4, 5 and 6mmol/L showed sensitivity and specificity greater than 70% for CSF lactate threshold 4mmol/L. The lowest threshold value of 3mmol/L resulted in higher sensitivity of 81.8%, and the highest chosen threshold value resulted in high specificity of 94.2%, but these values had poor corresponding specificity and sensitivity, respectively. The area under the curve was 0.82 (95% CI 0.72, 0.91). CONCLUSION: Our data from a large sample of CSF studies in patients with ventriculostomy indicate that no single value of CSF lactate provided both sensitivity and specificity high enough to be regarded as reliable test.
INTRODUCTION: In a febrile patient with a ventriculostomy, diagnosing or excluding bacterial or microbial ventriculitis is difficult, as conventional markers in analysis of cerebrospinal fluid (CSF) are not applicable due to presence of blood and inflammation. CSF lactate has been shown to be a useful indicator of bacterial meningitis in CSF obtained via lumbar puncture, but little and heterogenous data exist on patients with ventriculostomies. METHODS: We reviewed all CSF analyses obtained via ventriculostomy in patients admitted to our tertiary medical center between 2008 and 2013, and constructed receiver operating characteristic (ROC) curves to evaluate the accuracy of CSF lactate concentration in discriminating a positive CSF culture from a negative one in setting of ventriculostomy and prophylactic antibiosis. RESULTS: Among 467 CSF lactate values, there were 22 corresponding CSF cultures with bacterial growth. Sensitivities and specificities for CSF lactate at threshold values 3, 4, 5 and 6mmol/L showed sensitivity and specificity greater than 70% for CSF lactate threshold 4mmol/L. The lowest threshold value of 3mmol/L resulted in higher sensitivity of 81.8%, and the highest chosen threshold value resulted in high specificity of 94.2%, but these values had poor corresponding specificity and sensitivity, respectively. The area under the curve was 0.82 (95% CI 0.72, 0.91). CONCLUSION: Our data from a large sample of CSF studies in patients with ventriculostomy indicate that no single value of CSF lactate provided both sensitivity and specificity high enough to be regarded as reliable test.