A service evaluation comparing CVVH and CVVHDF in minimising circuit failure

Coagulation Risk Predicting in Anticoagulant-Free Continuous Renal Replacement Therapy

INTRODUCTION

Continuous renal replacement therapy (CRRT) is a prolonged continuous extracorporeal blood purification therapy to replace impaired renal function. Typically, CRRT therapy requires routine anticoagulation, but for patients at risk of bleeding and with contraindications to sodium citrate, anticoagulant-free dialysis therapy is necessary. However, this approach increases the risk of CRRT circuit coagulation, leading to treatment interruption and increased resource consumption. In this study, we utilized artificial intelligence machine learning methods to predict the risk of CRRT circuit coagulation based on pre-CRRT treatment metrics.

METHODS

We retrospectively analyzed 212 patients who underwent anticoagulant-free CRRT from October 2022 to October 2023. Patients were categorized into high-risk and low-risk groups based on CRRT circuit coagulation within 24 h. We employed eight machine learning methods to predict the risk of circuit coagulation. The performance of the model was evaluated using the area under the curve (AUC) of the receiver operating characteristic. 5-fold cross-validation was used to validate the machine learning models. Feature importance and SHAP plots were used to interpret the model's performance and key drivers.

RESULTS

We identified 88 patients (41.51%) at high risk of circuit coagulation within 24 h of CRRT. Our machine learning models showed excellent predictive performance, with ensemble learning achieving an AUC of 0.863 (95% CI: 0.860-0.868), outperforming individual algorithms. Random forest was the best single-algorithm model, with an AUC of 0.819 (95% CI: 0.814-0.823). The top three features identified as most important by the SHAP summary plot and feature importance graph are platelet, filtration fraction (FF), and triglycerides.

CONCLUSION

We created a model using machine learning to predict the risk of circuit coagulation during anticoagulant-free CRRT therapy. Our model performs well (AUC 0.863) and identifies key factors like platelets, FF, and triglycerides. This facilitates the development of personalized treatment strategies by clinicians aimed at reducing circuit coagulation risk, thereby enhancing patient outcomes and reducing healthcare expenses.

An evaluation of different dilution modes on circuit lifespan during continuous veno-venous hemodiafiltration without anticoagulation

BACKGROUND

Circuit clotting remains a major problem during continuous kidney replacement therapy (CKRT), particularly in patients with contraindications to anticoagulant use. We hypothesized that the different options of alternative replacement fluid infusion sites might affect circuit lifespan. However, research-based evidence supporting an optimal replacement fluid infusion strategy is limited. Therefore, we aimed to evaluate the effect of three dilution modes (pre-dilution, post-dilution, and pre- to post-dilution) on circuit lifespan during continuous veno-venous hemodiafiltration (CVVHDF).

METHODS

This prospective cohort study was conducted between December 2019 and December 2020. Patients requiring CKRT were enrolled to receive pre-dilution, post-dilution, or pre- to post-dilution fluid infusion with CVVHDF. The primary endpoint was circuit lifespan, and the secondary outcomes included the clinical parameters of patients, such as changes in serum creatinine (Scr) and blood urea nitrogen (BUN) levels, 28-day all-cause mortality, and length of stay. For all patients included in this study, only the first circuit used was recorded.

RESULTS

Among the 132 patients enrolled in this study, 40 were in the pre-dilution mode, 42 were in the post-dilution mode, and 50 were in the pre- to post-dilution mode. The mean circuit lifespan was significantly longer in the pre- to post-dilution group (45.72 h, 95% CI, 39.75-51.69 h) than in the pre-dilution group (31.58 h, 95% CI, 26.33-36.82 h) and the post-dilution group (35.20 h, 95% CI, 29.62-40.78 h). There was no significant difference between the pre- and post-dilution group circuit lifespan (p > 0.05). Kaplan-Meier survival analysis revealed a significant difference between the three dilution modes (p = 0.001). No significant differences were observed in terms of changes in the Scr and BUN levels, admission day, and 28-day all-cause mortality among the three dilution groups (p > 0.05).

CONCLUSION

The pre- to post-dilution mode significantly prolonged circuit lifespan but did not reduce Scr and BUN levels, compared with the pre-dilution and post-dilution modes during CVVHDF when no anticoagulants were used.

Comparison of different modalities of continuous renal replacement therapy with regional sodium citrate anticoagulation in paediatric patients

BACKGROUND

To evaluate the efficacy and safety of continuous renal replacement therapy (CRRT) modalities with regional sodium citrate anticoagulation (RCA) in children.

METHODS

This retrospective study was conducted at the paediatric intensive care unit of Hunan Children's Hospital in China. Medical records of paediatric patients hospitalised for RCA-CRRT between April 2017 and March 2021 were reviewed. Patients received continuous venovenous haemodialysis, continuous venovenous haemofiltration (CVVH), or continuous venovenous haemodiafiltration (CVVHDF).

RESULTS

Patients on continuous venovenous haemodialysis (n = 2) were excluded because of their small sample size. The remaining participants were divided into CVVH and CVVHDF groups; 80 patients received CRRT, with 40 and 62 sessions in the CVVH and CVVHDF groups, respectively. The filtre lifespan was longer in the CVVHDF group than in the CVVH group (median value [interquartile range]; 47 [15] hours vs. 35 [17.5] hours; p = 0.029). Compared with the CVVHDF group, the hazard ratio for filtre lifespan in the CVVH group was 3.023 (95% confidence interval 1.820-5.023, p < 0.001). There were no significant differences in ionised calcium levels of the circuits between the two groups at different time points (p < 0.05). Metabolic alkalosis, hyperlactataemia, hypocalcaemia, and hypercalcaemia occurred in both groups, with metabolic alkalosis being the most common complication. No patients in either group experienced sodium citrate accumulation or hypernatraemia. Inter-group differences in the incidence of these complications were not statistically significant (p > 0.05).

CONCLUSIONS

Our results suggest that CVVHDF is a better option for RCA-CRRT than CVVH.

Non anti-coagulant factors associated with filter life in continuous renal replacement therapy (CRRT): a systematic review and meta-analysis

BACKGROUND

Optimising filter life and performance efficiency in continuous renal replacement therapy has been a focus of considerable recent research. Larger high quality studies have predominantly focussed on optimal anticoagulation however CRRT is complex and filter life is also affected by vascular access, circuit and management factors. We performed a systematic search of the literature to identify and quantify the effect of vascular access, circuit and patient factors that affect filter life and presented the results as a meta-analysis.

METHODS

A systematic review and meta-analysis was performed by searching Pubmed (MEDLINE) and Ovid EMBASE libraries from inception to 29th February 2016 for all studies with a comparator or independent variable relating to CRRT circuits and reporting filter life. Included studies documented filter life in hours with a comparator other than anti-coagulation intervention. All studies comparing anticoagulation interventions were searched for regression or hazard models pertaining to other sources of variation in filter life.

RESULTS

Eight hundred nineteen abstracts were identified of which 364 were selected for full text analysis. 24 presented data on patient modifiers of circuit life, 14 on vascular access modifiers and 34 on circuit related factors. Risk of bias was high and findings are hypothesis generating. Ranking of vascular access site by filter longevity favours: tunnelled semi-permanent catheters, femoral, internal jugular and subclavian last. There is inconsistency in the difference reported between femoral and jugular catheters. Amongst published literature, modality of CRRT consistently favoured continuous veno-venous haemodiafiltration (CVVHD-F) with an associated 44% lower failure rate compared to CVVH. There was a trend favouring higher blood flow rates. There is insufficient data to determine advantages of haemofilter membranes. Patient factors associated with a statistically significant worsening of filter life included mechanical ventilation, elevated SOFA or LOD score, elevations in ionized calcium, elevated platelet count, red cell transfusion, platelet factor 4 (PF-4) antibodies, and elevated fibrinogen. Majority of studies are observational or report circuit factors in sub-analysis. Risk of bias is high and findings require targeted investigations to confirm.

CONCLUSION

The interaction of patient, pathology, anticoagulation, vascular access, circuit and staff factors contribute to CRRT filter life. There remains an ambiguity from published data as to which site and side should be the first choice for vascular access placement and what interaction this has with patient factors and timing. Early consideration of tunnelled semi-permanent access may provide optimal filter life if longer periods of CRRT are anticipated. There remains an absence of robust evidence outside of anti-coagulation strategies despite over 20 years of therapy delivery however trends favour CVVHD-F over CVVH.