Application of combined cerebrospinal fluid physicochemical parameters to detect intracranial infection in neurosurgery patients

Application of a six sigma model to evaluate the analytical performance of cerebrospinal fluid biochemical analytes and the design of quality control strategies for these assays: A single-centre study

BACKGROUND

In this study, we applied a six sigma model to examine cerebrospinal fluid (CSF) biochemical analytes for the first time. Our goal was to evaluate the analytical performance of various CSF biochemical analytes, design an optimized internal quality control (IQC) strategy, and formulate scientific and reasonable improvement plans.

METHODS

The sigma values of CSF total protein (CSF-TP), albumin (CSF-ALB), chloride (CSF-Cl), and glucose (CSF-GLU) were calculated using the following formula: sigma = [TEa(%)-|bias(%)|]/CV(%). The analytical performance of each analyte was shown using a normalized sigma method decision chart. Individualized IQC schemes and improvement protocols for CSF biochemical analytes were formulated using the Westgard sigma rule flow chart with batch size and quality goal index (QGI).

RESULTS

The distribution of sigma values for CSF biochemical analytes ranged from 5.0 to 9.9, and the sigma values varied for different concentrations of the same analyte. The analytical performance of the CSF assays at the two QC levels is displayed visually in normalized sigma method decision charts. Individualized IQC strategies for CSF biochemical analytes were as follows: for CSF-ALB, CSF-TP and CSF-Cl, use 1_3s with N = 2 and R = 1000; for CSF-GLU, use 1_3s/2_2s/R_4s with N = 2 and R = 450. In addition, priority improvement measures for analytes with sigma values less than 6 (CSF-GLU) were formulated based on the QGI, and their analytical performance was improved after the corresponding improvement measures were taken.

CONCLUSIONS

The six sigma model has significant advantages in practical applications involving CSF biochemical analytes and is highly useful for quality assurance and quality improvement.

Analysis of Cerebrospinal Fluid Routine Biochemical Level, Pathogenic Bacteria Distribution, and Risk Factors in Patients with Secondary Intracranial Infection after Brain Tumor Surgery

Purpose. Analysis of routine biochemical levels of cerebrospinal fluid (CSF), distribution of pathogenic bacteria, and risk factors in patients with intracranial infections secondary to brain tumour surgery. Methods. A total of 208 patients admitted to our hospital for brain tumour surgery from January 2020 to May 2022 were selected. Fully automated biochemical analyzer was employed for CSF routine and for measuring biochemical parameters such as white blood cell (WBC), micrototal protein (M-TP), glucose (GLU), and chlorine (CI). Double antibody sandwich assay for CSF procalcitonin (PCT), heparin-binding protein (HBP), and matrix metalloproteinase-9 (MMP-9) was performed. Fully automated microbiological analyzer for pathogen identification was utilized. Based on the above results, we determined whether the patients had secondary intracranial infections after surgery and analyzed the risk factors for secondary intracranial infections after brain tumour surgery by univariate and multifactorial logistic regression. Results. Among 208 patients with brain tumour surgery, 65 cases (31.25%) had secondary intracranial infection and 143 cases (68.75%) had no secondary intracranial infection. The levels of WBC, M-TP, CI, PCT, HBP, and MMP-9 in the CSF of intracranially infected patients were significantly higher than those of uninfected patients ( $P<0.05$ ), and GLU was significantly lower than that of uninfected patients ( $P<0.05$ ), and the levels of PCT, HBP, and MMP-9 in infected patients were significantly lower than those before treatment after 3, 7, and 10 d and tended to decrease over time ( $P<0.05$ ). A total of 62 pathogenic strains were isolated from 65 intracranial infections, of which 41 (66.13%) were Gram-negative bacteria, mainly resistant to amikacin and ciprofloxacin and sensitive to meropenem and imipenem; 19 (30.65%) were Gram-positive bacteria, mainly highly resistant to penicillin and erythromycin and sensitive to vancomycin. Univariate analysis showed that age, gender, tumour type, history of glucocorticoid application, and prophylactic application of antibiotics were not associated with secondary intracranial infection after brain tumour surgery ( $P>0.05$ ); tumour site, operation time, postoperative indwelling drainage time, postoperative cerebrospinal fluid leakage, and history of diabetics were all associated with secondary intracranial infection after brain tumour surgery ( $P<0.05$ ). Multivariate logistic regression analysis showed that infratentorial tumour, operation time ≥4 h, postoperative indwelling drainage time ≥24 h, and postoperative cerebrospinal fluid leakage were independent risk factors for secondary intracranial infection after brain tumour surgery ( $P<0.05$ ). Conclusion. Patients with intracranial infections secondary to brain tumour surgery have abnormal levels of CSF routine and biochemical parameters, and the detection rate of Gram-negative bacteria is higher than that of Gram-positive bacteria in patients. Treatment should be based on the characteristics of pathogenic bacteria and risk factors with targeted interventions to reduce intracranial infections.

Self-Assembled Au Nanoparticle Arrays for Precise Metabolic Assay of Cerebrospinal Fluid

Precise and rapid monitoring of metabolites in biofluids is a desirable but unmet goal for disease diagnosis and management. Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) exhibits advantages in metabolite analysis. However, the low accuracy in quantification of the technique limits its transformation to clinical usage. We report herein the use of Au nanoparticle arrays self-assembled at liquid-liquid interfaces for mass spectrometry (MS)-based quantitative biofluids metabolic profiling. The two-dimensional arrays feature uniformly and closely packed Au nanoparticles with 3 nm interparticle gaps. The experimental study and theoretical simulation show that the arrays exhibit high photothermal conversion and heat confinement effects, which enhance the laser desorption/ionization efficacy. With the nanoscale roughness, the AuNP arrays as laser desorption/ionization substrates can interrupt the coffee-ring effect during droplet evaporation. Therefore, high reproducibility (RSD <5%) is obtained, enabling accurate quantitative analysis of diverse metabolites from 1 μL of biofluids in seconds. By quantifying glucose in the cerebrospinal fluid (CSF), it allows us to identify patients with brain infection and rapidly evaluate the clinical therapy response. Consequently, the method shows potential in advanced metabolite analysis and biomedical diagnostics.

The risk factors of intracranial infection in patients with intracerebral hemorrhage undergone hematoma puncture: what should we care

BACKGROUND

Intracranial infection after puncture of cerebral hematoma in patients with intracerebral hemorrhage is very common in the department of neurosurgery, yet the relevant risks remain unknown. We attempted to analyze the risk factors of intracranial infection after puncture of cerebral hematoma, to provide insights into the management of patients with intracerebral hemorrhage after puncture of cerebral hematoma.

METHODS

Patients with intracerebral hemorrhage after puncture of cerebral hematoma treated in our hospital from January 2017 to January 2020 were selected, the related characteristics of intracranial infection and no infection patients were compared. Logistic regression analyses were conducted to analyze the risk factors for intracranial infection after puncture of cerebral hematoma.

RESULTS

A total of 925 patients with puncture of cerebral hematoma were included. The incidence of postoperative intracranial infection was 7.03%. There were significant statistical differences between the infected group and the no infection group in the American Association of Anesthesiologists (ASA) grade, length of hospital stay, consecutive operation, duration of surgery, extra-ventricular drainage (EVD) use (all p < 0.05). There was statistically significant difference in the duration of EVD between the infection and no infection groups (p = 0.002), and there was no significant difference in the frequency of EVD insertion between the two groups (p = 0.094). The length of hospital stay≥10 days (OR1.832, 1.062-3.158), consecutive operation (OR2.158, 1.358-3.430), duration of surgery≥4 h (OR1.581, 1.031-2.425), EVD use (OR1.694, 1.074-2.670), and duration of EVD ≥ 7 days (OR2.699, 1.689-4.311) were the risk factors of intracranial infection in patients with intracerebral hemorrhage after puncture of cerebral hematoma (all p < 0.05).

CONCLUSION

Clinical medical workers should take corresponding preventive measures against the different risk factors for prevention of intracranial infection in patient with puncture of cerebral hematoma.