The effect of different flushing and locking techniques on catheter occlusion rates in central venous catheters: protocol for a multicentre, randomized controlled, parallel-group, open-label, superiority clinical trial.

BACKGROUND: Maintaining venous access is of great clinical importance. Running a slow continuous infusion to keep the vein open (KVO) is often used in peripheral intravenous catheters (PIVCs). Previous studies have compared the effects of intermittent flushing and continuous infusion via peripherally inserted central catheters (PICCs). In this study, we applied KVO to central venous catheters (CVCs) and compared the occlusion rate of this technique with that of the intermittent flushing technique. METHOD: This is a randomized controlled trial of 14 hospitals in China. A total of 250 patients will be recruited in this study, and they will be randomized at a 1:1 ratio. After study inclusion, patients who will undergo CVC insertion will receive intermittent flushing with prefilled saline syringes (control group) or KVO infusion with elastic pumps (test group). All the catheters will be checked for patency by scoping Catheter Injection and Aspiration (CINAS) Classification on Days 3 and 7. The primary outcome is the rate of catheter occlusion in 7 days. Patients will be followed up until 9 days after CVC insertion, catheter occlusion, or catheter removal. The secondary outcomes are the rate of catheter occlusion in 3 days, nurse satisfaction, cost-effectiveness, adverse event rate, catheter-related bloodstream infection rate, catheter-related thrombosis rate, extravasation rate, phlebitis rate, and catheter migration. DISCUSSION: We expect that the trial will generate findings that can provide an evidence-based basis for the improvement and optimization of clinical catheter flushing techniques. TRIAL REGISTRATION: Chinese Clinical Trial Registry, ChiCTR2200064007. Registered on 23 September 2022. https://www.chictr.org.cn/showproj.html?proj=177311 .

Autophagy is induced by anti-neutrophil cytoplasmic Abs and promotes neutrophil extracellular traps formation.

Dysregulated neutrophil extracellular traps (NETs) formation contributes to the pathogenesis of anti-neutrophil cytoplasmic Ab (ANCA)-associated vasculitis (AAV). Increasing evidence indicates that autophagy is involved in the process of NETs formation. In this study, we aimed to investigate whether ANCA could induce autophagy in the process of NETs formation. Autophagy was detected using live cell imaging, microtubule-associated protein light chain 3B (LC3B) accumulation and Western blotting. The results showed that autophagy vacuolization was detected in neutrophils treated with ANCA-positive IgG by live cell imaging. This effect was enhanced by rapamycin, the autophagy inducer, and weakened by 3-methyladenine (3-MA), the autophagy inhibitor. In line with these results, the autophagy marker, LC3B, showed a punctate distribution pattern in the neutrophils stimulated with ANCA-positive IgG. In the presence of rapamycin, LC3B accumulation was further increased; however, this effect was attenuated by 3-MA. Moreover, incubated with ANCA-positive IgG, the NETosis rate significantly increased compared with the unstimulated group. And, the rate significantly increased or decreased in the neutrophils pretreated with rapamycin or 3-MA, respectively, as compared with the cells incubated with ANCA-positive IgG. Overall, this study demonstrates that autophagy is induced by ANCA and promotes ANCA-induced NETs formation.

Circulating Level of Neutrophil Extracellular Traps Is Not a Useful Biomarker for Assessing Disease Activity in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis.

Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a group of life-threatening disorders, and frequently affects the kidneys. This study investigated whether the circulating neutrophil extracellular traps (NETs) levels were associated with disease activity of AAV. We collected serum samples from 34 patients with AAV in active stage and 62 patients with AAV in remission. Cell free DNA in serum was quantified using the Quant-iT PicoGreen assay. NETs associated MPO-DNA complexes, citrullinated-histone H3-DNA (cit-H3-DNA) complexes and the concentration of deoxyribonuclease I (DNase I) were quantified using ELISA. The activity of DNase I was quantified using radial enzyme-diffusion method. Associations between circulating levels of NETs with clinico-pathological parameters were analyzed. Serum levels of NETs in active AAV patients were significantly higher than those in healthy controls, and the level of cell free DNA correlated with C-reactive protein (CRP). However, no correlation was found between MPO-DNA complexes or cit-H3-DNA complexes level and CRP. Also there was no significant correlation between NETs level and initial serum creatinine, estimated glomerular filtration rate (eGFR), crescents formation or Birmingham Vasculitis Activity Score (BVAS). Furthermore, there was no significant difference of serum levels of cell free DNA or MPO-DNA complexes between active stage and remission of AAV. In conclusion, circulating levels of NETs cannot be used as a biomarker to assess disease activity in AAV patients.