Cerebrospinal fluid cell count variability is a major confounding factor in external ventricular drain-associated infection surveillance diagnostics: a prospective observational study

The effect of machine learning algorithms in the prediction, and diagnosis of meningitis: A systematic review

Background and Aims

This systematic review aimed to evaluating the effectiveness of machine learning (ML) algorithms for the prediction and diagnosis of meningitis.

Methods

On November 12, 2022, a systematic review was carried out using a keyword search in the reliable scientific databases PubMed, EMBASE, Scopus, and Web of Science. The recommendations of Preferred Reporting for Systematic Reviews and Meta-Analyses (PRISMA) were adhered to. Studies conducted in English that employed ML to predict and identify meningitis were deemed to match the inclusion criteria. The eligibility requirements were used to independently review the titles and abstracts. The whole text was then obtained and independently reviewed in accordance with the eligibility requirements.

Results

After all the research matched the inclusion criteria, a total of 16 studies were added to the systematic review. Studies on the application of ML algorithms in the three categories of disease diagnosis ability (8.16) and disease prediction ability (8.16) (including cases related to identifying patients (50%), risk of death in patients (25%), the consequences of the disease in childhood (12.5%), and its etiology [12.5%]) were placed. Among the ML algorithms used in this study, logistic regression (LR) (4.16, 25%) and multiple logistic regression (MLR) (4.16, 25%) were the most used. All the included studies indicated improvements in the processes of diagnosis, prediction, and disease outbreak with the help of ML algorithms.

Conclusion

The results of the study showed that in all included studies, ML algorithms were an effective approach to facilitate diagnosis, predict consequences for risk classification, and improve resource utilization by predicting the volume of patients or services as well as discovering risk factors. The role of ML algorithms in improving disease diagnosis was more significant than disease prediction and prevalence. Meanwhile, the use of combined methods can optimize differential diagnoses and facilitate the decision-making process for healthcare providers.

Combination of Conventional EVD and Ommaya Drainage for Intraventricular Hemorrhage (IVH)

Background

The effect of Ommaya reservoirs on the clinical outcomes of patients with intraventricular hemorrhage (IVH) remains unclear.

Objective

We aimed to determine the effect of combining the Ommaya reservoir and external ventricular drainage (EVD) therapy on IVH and explore better clinical indicators for Ommaya implantation.

Methods

A retrospective analysis was conducted on patients diagnosed with IVH who received EVD-Ommaya drainage between January 2013 and March 2021. The patient population was divided into two groups: the Ommaya-used group, comprising patients in whom the Ommaya drainage system was activated post-surgery, and the Ommaya-unused group, comprising patients in whom the system was not activated. The study analyzed clinical, imaging, and outcome data of the patient population.

Results

A total of 123 patients with IVH were included: 75 patients in the Ommaya-used group and 48 patients in the Ommaya-unused group. The patients in the Ommaya-used group showed a lower 3-month GOS than those in the Ommaya-unused group (p<0.0001). The modified Graeb scale (mGS) in the Ommaya-unused group was significantly lower than that in the Ommaya-used group before the operation (p<0.01) but not after surgery (p>0.05). The GCS in the Ommaya-unused group was significantly lower than that in the other group, and there was a close correlation between the GCS and 3-month GOS (p<0.0001). The GCS score showed significance in predicting the use of Ommaya (p<0.001).

Conclusion

The study demonstrated that combining EVD and Ommaya drainage was a safe and feasible treatment for IVH. Additionally, preoperative GCS was found to predict the use of Ommaya drainage in subsequent treatment, providing valuable information for pre-surgery decision-making.

Cerebrospinal fluid analysis of metabolites is not correlated to microdialysis measurements in acute brain injured patients

BACKGROUND

Cerebral microdialysis (CMD) has become an established bedside monitoring modality but its implementation remains complex and costly and is therefore performed only in a few well-trained academic centers. This study investigated the relationship between cerebrospinal fluid (CSF) and CMD glucose and lactate concentrations.

METHODS

Two centers retrospective study of prospectively collected data. Consecutive adult (>18 years) acutely brain injured patients admitted to the Intensive Care Unit between 2010 and 2021 were eligible if CSF and CMD glucose and lactate concentrations were concomitantly measured at least once.

RESULTS

Of 113 patients being monitored with an external ventricular drainage and CMD, 49 patients (25 from Innsbruck and 24 from Brussels) were eligible for the final analysis, including a total of 96 measurements. Median CMD glucose and lactate concentrations were 1.15 (0.51-1.57) mmol/L and 3.44 (2.24-5.37) mmol/L, respectively; median CSF glucose and lactate concentrations were 4.67 (4.03-5.34) mmol/L and 3.40 (2.85-4.10) mmol/L, respectively. For the first measurements, no correlation between CSF and CMD glucose concentrations (R2 <0.01; p = 0.95) and CSF and CMD lactate concentrations (R2 =0.16; p = 0.09) was found. Considering all measurements, the repeated measure correlation analysis also showed no correlation for glucose (rrm = -0.01; 95% Confidence Intervals -0.306 to 0.281; p = 0.93) and lactate (rrm = -0.11; 95% Confidence Intervals -0.424 to 0.236; p = 0.55).

CONCLUSIONS

In this study including acute brain injured patients, no correlation between CSF and brain tissue measurements of glucose and lactate was observed. As such, CSF measurements of such metabolites cannot replace CMD findings.

Heparin-binding protein as a marker of ventriculostomy related infection and central nervous system inflammation in neuro-intensive care

OBJECTIVE

Diagnosis of ventriculostomy related infections (VRI) in the neuro-intensive care unit remains challenging and current biomarkers lack adequate precision. The aim of this study was to explore the potential of Heparin-binding protein (HBP) in cerebrospinal fluid (CSF) as a diagnostic biomarker of VRI.

METHODS

All patients treated with an external ventricular drain (EVD) between January 2009 and March 2010 at Skåne university hospital in Lund, Sweden, were consecutively included. CSF samples obtained during routine care were analyzed for HBP. VRI was defined as a positive bacterial microbiology test result on a CSF sample with an erythrocyte-corrected leukocyte count of > 50 × 10⁶/l. HBP levels at VRI diagnosis was compared to peak HBP levels in non-VRI controls.

RESULTS

In total, 394 CSF samples from 103 patients were analyzed for HBP. Seven patients (6.8%) fulfilled VRI criteria. Levels of HBP were significantly higher in VRI subjects (31.7 ng/mL [IQR 26.9-40.7 ng/mL]) compared to non-VRI controls (7.7 ng/mL [IQR 4.1-24.5 ng/mL]) (p = 0.024). The AUC of the receiver operating characteristic (ROC) curve was 0.76 (95% confidence interval [CI], 0.62-0.90). Among non-VRI patients, HBP was highest in patients with acute bacterial meningitis. Patients with subarachnoid hemorrhage displayed higher HBP levels than those with traumatic brain injury or shunt dysfunction.

CONCLUSIONS

HBP levels were higher in VRI subjects and varied between patients and different diagnoses. To validate the clinical usefulness and added value of HBP as a biomarker for VRI, the results need to be confirmed in larger studies with head-to-head comparisons to current biomarkers.

Changes of serum NSE, lactate and CRP in patients with postoperative infection after acute craniocerebral injury and their predictive value for prognosis

To investigate the changes of serum neuron-specific enolase (NSE), lactate and C-reactive protein (CRP) in patients with postoperative infection after acute craniocerebral injury and their predictive value for prognosis. 71 patients with postoperative infection after acute craniocerebral injury were selected as infection group, and 56 patients without postoperative infection were selected as non-infection group. NSE, CRP and blood lactic acid levels were detected in all patients. The relationship between each index and thecondition and prognosis of patients was analyzed. The levels of serum NSE, lactic acid and CRP in infected group were higher than those in non-infection group (P<0.05). The levels of serum NSE, lactic acid and CRP in severe group were higher than those in mild group (P<0.05). Serum levels of NSE, lactic acid and CRP were positively correlated with the severity of infection (P<0.05), the area under the curve (AUC) of the receiver operating characteristic curve (ROC) was greater than that of the NSE level (P<0.05). The levels of serum NSE, lactate and CRP in the good prognosis group were lower than those in the poor prognosis group (P<0.05). The area under the curve (AUC) of receiver operating characteristic curve (ROC) of lactate level in predicting the prognosis of patients with infection was higher than that of NSE and CRP (P<0.05). Serum NSE, lactic acid and CRP have predictive value in patients with acute craniocerebral injury.

Cerebrospinal fluid white cell count to red cell count ratio as a predictor of ventriculitis in patients with external ventricular drains

INTRODUCTION

External ventricular drain (EVD) associated ventriculitis is a complication of EVD placement associated with significant morbidity and mortality. Gold-standard for EVD associated bacterial ventriculitis diagnosis involves cerebrospinal fluid (CSF) sampling from the EVD with microscopy, culture and sensitivity testing. The ratio of white blood cells to red blood cells has anecdotally been considered a predictive factor in diagnosing EVD associated ventriculitis, however no study has been done demonstrating this.

METHODS

A retrospective cross-sectional study was designed to assess whether the ratio of CSF white blood cells to red blood cells could be used to diagnose EVD associated ventriculitis. Data was collected for all patients undergoing EVD insertion at a major neurosurgical unit in Sydney, Australia. A receiver operator characteristics (ROC) curve was used to determine if this ratio was useful, and Youden's index was calculated to determine the appropriate cut-off point.

RESULTS

This sample of n = 157 consecutive patients a total of 29 patients were diagnosed with ventriculitis. The area under the ROC curve was significant (0.706, P <0.001), and Youden's index demonstrated an appropriate cut-off point was a ratio of 1:106.

DISCUSSION

CSF parameters have long been considered predictive of EVD associated ventriculitis. We demonstrated that using a component of routine testing it is possible to accurately predict a ventriculitis diagnosis. As the ratio is used, it enables discrimination in a raised white blood cell count due to local trauma with interventricular bleeding.

CONCLUSION

CSF white blood cell to red blood cell ratio is an appropriate diagnostic test for ventriculitis.

Spatial and temporal variation of routine parameters: pitfalls in the cerebrospinal fluid analysis in central nervous system infections

The cerebrospinal fluid (CSF) space is convoluted. CSF flow oscillates with a net flow from the ventricles towards the cerebral and spinal subarachnoid space. This flow is influenced by heartbeats, breath, head or body movements as well as the activity of the ciliated epithelium of the plexus and ventricular ependyma. The shape of the CSF space and the CSF flow preclude rapid equilibration of cells, proteins and smaller compounds between the different parts of the compartment. In this review including reinterpretation of previously published data we illustrate, how anatomical and (patho)physiological conditions can influence routine CSF analysis. Equilibration of the components of the CSF depends on the size of the molecule or particle, e.g., lactate is distributed in the CSF more homogeneously than proteins or cells. The concentrations of blood-derived compounds usually increase from the ventricles to the lumbar CSF space, whereas the concentrations of brain-derived compounds usually decrease. Under special conditions, in particular when distribution is impaired, the rostro-caudal gradient of blood-derived compounds can be reversed. In the last century, several researchers attempted to define typical CSF findings for the diagnosis of several inflammatory diseases based on routine parameters. Because of the high spatial and temporal variations, findings considered typical of certain CNS diseases often are absent in parts of or even in the entire CSF compartment. In CNS infections, identification of the pathogen by culture, antigen detection or molecular methods is essential for diagnosis.