Faster Blood Flow Rate Does Not Improve Circuit Life in Continuous Renal Replacement Therapy: A Randomized Controlled Trial

Intervention measures to improve the filter life of continuous renal replacement therapy in critically ill patients-A systematic review

BACKGROUND

Continuous renal replacement therapy (CRRT) is a method of blood purification, which is widely used in the treatment of critical diseases as a means of multiple organ function protection and life support therapy. However, because of the serious condition of ICU (intensive care unit) patients, CRRT needs to be carried out continuously, but the treatment is interrupted ahead of time as a result of various conditions, which not only affects the treatment effect but also increases the patient cost.

AIMS

To evaluate intervention measures to improve the filter life of CRRT in critically ill patients, and also to identify which interventions are considered 'promising interventions'.

STUDY DESIGN

This is a systematic review. Seven databases were searched using terms related to the concepts of 'continuous renal replacement therapy' and 'filter life', from the establishment of the database to 31 December 2023. The quality of the methodology included in the study was assessed using standard evaluation tools developed by the Effective Public Health Practice Project (EPHPP), and pre-established criteria were used to identify 'promising interventions'.

RESULTS

A total of 28 studies were included, of which 7 were rated 'strong' in terms of design and methodological quality, and the others were 'medium'. The most commonly identified interventions to extend the life of CRRT filters include the use of sodium citrate anticoagulation, the choice of CVVHD or CVVHDF or pre-diluted CVVH for CRRT and the use of personalized sodium citrate anticoagulant regimens to reduce the incidence of filter clotting. The intervention measures of 14 studies were statistically significant, while the other 14 studies were not statistically significant. Interventions in nine studies were identified as 'promising interventions' because they were published within 10 years, with a medium or strong methodological quality rating, significant positive results and a strong evidence base.

CONCLUSION

In the promising interventions study, citrate anticoagulation and CVVHD or CVVHDF models were recommended to significantly prolong filter life. However, more high-quality studies are needed to identify interventions that can prolong the life of CRRT filters in critically ill patients, thereby supplementing the literature in this field. The existing studies lack blinding and have limited quality. Future studies should be carried out with the goal of 'best evidence', and the interventions should be more universal and clinically practical.

RELEVANCE TO CLINICAL PRACTICE

This study uses the method of systematic review to scientifically and rigorously provide some suggestions for extending the life of CRRT filters in critically ill patients, such as 'By implementing personalized citrate anticoagulation protocols, the incidence of CRRT filter life shortening due to coagulation can be reduced', which can reduce the cost of patients and improve the quality of treatment to a certain extent in clinical practice.

Risk factors for unplanned weaning of continuous renal replacement therapy in ICU patients: a meta-analysis

OBJECTIVE

To systematically review the risk factors for unplanned weaning during continuous renal replacement therapy in ICU patients.

METHODS

A combination of subject words + free words was used to search the relevant literature published in CNKI, Wanfang, VIP, CBM, PubMed, EMbase, Web of Science, Cochrane Library, Mediline and other databases. The search period was from the establishment of the databases to June 25, 2024. Revman 5.4 software and Stata15.0 software was used to meta-analyze the risk factors for unplanned weaning during continuous renal replacement therapy in ICU patients.

RESULTS

A total of 23 studies were included in this meta-analysis, describing 15 variables, 3793 patients, and using 7197 filters. Meta-analysis results showed that risk factors for unplanned weaning during continuous renal replacement therapy in ICU patients were as follows: Low mean arterial pressure [OR = 1.02, 95%CI (1.00, 1.03), p < 0.05], hypothermia [OR = 3.40, 95%CI (1.78, 6.47), p < 0.05], age (≥60 years) [OR = 4.45, 95%CI (3.18, 6.22), p < 0.05], comorbid underlying disease [OR = 3.63, 95%CI (2.70, 4.88), p < 0.05], agitation [OR = 4.97, 95%CI (3.20, 7.74), p < 0.05], no anticoagulant use [OR = 1.65, 95%CI (1.25, 2.17), p < 0.05], short activated partial prothrombin time [OR = 1.23, 95%CI (1.13, 1.34), p < 0.05], hyper-hematocrit [OR = 1.73, 95%CI (1.13, 2.66), p = 0.01], low ionized calcium concentration [OR = 1.48, 95% CI (1.08, 2.02), p = 0.01], CRRT that was treated at a high dose [OR = 1.42, 95%CI (1.14, 1.76), p < 0.05], mechanical ventilation [OR = 4.25, 95%CI (2.67, 6.77), p < 0.05], and lack of dedicated care [OR = 5.08, 95%CI (2.51, 10.28), p < 0.05]. However, it is unclear whether platelet count, prothrombin activity, and blood flow velocity are risk factors for unplanned weaning during CRRT in ICU patients, and more studies are needed for further validation.

CONCLUSION

Available evidence suggests that a variety of factors contribute to unplanned weaning of CRRT in ICU patients. Early detection of these risk factors is essential for healthcare professionals to develop preventive and curative strategies.

REGISTRATION

This study is registered on the PROSERO website under registration number CRD42024543554.

Development and Validation of a Coagulation Risk Prediction Model for Anticoagulant-Free Hemodialysis: Enhancing Hemodialysis Safety for Patients

INTRODUCTION

This study aimed to develop and validate a risk prediction model for predicting the likelihood of coagulation in patients undergoing anticoagulant-free hemodialysis (HD). Anticoagulant-free HD technique is necessary in patients with contraindications to systemic therapy. Coagulation is a complication of this technique. Unfortunately, no predictive model is currently available to assess the risk of coagulation in anticoagulant-free HD.

METHODS

We retrospectively analyzed the clinical data from 299 HD sessions involving 164 patients who underwent anticoagulant-free HD between January 2022 and June 2023. To identify the risk factors for coagulation in anticoagulant-free HD, a univariate analysis was performed on 18 independent variables. Logistic regression was used to establish predictive models by identifying factors contributing to coagulation in anticoagulant-free HD. A calibration curve was drawn using regression coefficients and 1,000 bootstrap repetitions to validate our model internally. The performance of the prediction model was evaluated using receiver operating characteristic, area under the curve (AUC), and decision curve analysis (DCA).

RESULTS

The incidence of coagulation in patients on anticoagulant-free HD was 35.1%. Logistic regression analysis showed that platelet (PLT), hematocrit (HCT) levels, dialysate type, and age were risk factors for coagulation in anticoagulant-free HD patients (p < 0.05). The Hosmer-Lemeshow test showed p = 0.29, and the AUC is 0.76 (95% CI 0.70-0.80). The optimal critical value was 0.40, yielding a sensitivity of 61.0%, a specificity of 80.4%, and a Youden index of 0.41.

CONCLUSION

In anticoagulant-free HD, there were numerous risk factors and a 35.1% occurrence of coagulation. The constructed coagulation risk prediction model exhibited good predictive and clinical utility and could serve as a reference for the initial assessment and screening of coagulation risk in anticoagulant-free HD.

Filter Lifespan, Treatment Effect, and Influencing Factors of Continuous Renal Replacement Therapy for Severe Burn Patients

Continuous renal replacement therapy (CRRT) is often disrupted due to various factors, such as patient-related issues, vascular access complications, treatment plans, and medical staff factors. This unexpected interruption is referred to as non-selective filter stoppage and can result in additional treatment expenses. This study conducted a retrospectively analyzed 501 CRRT filters used in 62 patients with severe burns, lifespan and therapeutic effect of all filters were mainly analyzed, used logistic regression analysis was performed to identify risk factors associated with non-selective cessation filters. Out of 493 filters, 279 cases received heparin (56.60%), the median lifespan of the filter was 14.08 h (25th, 75th quantile: 7.30, 21.50); 128 cases were treated with nafamostat mesylate (26.00%), and the median lifespan of the filter was 16.42 h (10.49, 22.76); 86 cases were treated with sodium citrate (17.40%), and the median lifespan of the filter was 31.06 h (19.25, 48.75). In addition, significant differences were observed in the electrolyte index, renal function index, and procalcitonin levels before and after treatment with a single filter (P < .001). Multivariate logistic regression showed that the risk of non-selective cessation of sodium citrate anticoagulants was lower than that of heparin anticoagulation. Overall, CRRT is progressively becoming more prevalent in the treatment of patients with severe burns. The lifespan of individual filters and total patient treatment duration showed a consistent upward trend. The filter's lifespan was notably greater during sodium citrate anticoagulation when compared to nafamostat mesylate and heparin, meanwhile notably reducing the risk of non-selective cessation. Therefore, we recommend sodium citrate for anticoagulation in patients without any contraindications.

Continuous KRT: A Contemporary Review

AKI is a common complication of critical illness and is associated with substantial morbidity and risk of death. Continuous KRT comprises a spectrum of dialysis modalities preferably used to provide kidney support to patients with AKI who are hemodynamically unstable and critically ill. The various continuous KRT modalities are distinguished by different mechanisms of solute transport and use of dialysate and/or replacement solutions. Considerable variation exists in the application of continuous KRT due to a lack of standardization in how the treatments are prescribed, delivered, and optimized to improve patient outcomes. In this manuscript, we present an overview of the therapy, recent clinical trials, and outcome studies. We review the indications for continuous KRT and the technical aspects of the treatment, including continuous KRT modality, vascular access, dosing of continuous KRT, anticoagulation, volume management, nutrition, and continuous KRT complications. Finally, we highlight the need for close collaboration of a multidisciplinary team and development of quality assurance programs for the provision of high-quality and effective continuous KRT.

Circuit haemodynamics during non-citrate and regional citrate continuous renal replacement, and impact of blood flow on filter life

BACKGROUND

During continuous renal replacement therapy (CRRT) with regional citrate anticoagulation (RCA), blood flow (Qb) might affect vascular access dysfunction (AD) and, thereby, circuit life.

METHODS

Circuit life and circuit haemodynamics were studied in three intensive care units (ICUs) by analysing hemofilter device data (Prismaflex^®, Baxter, Chicago, IL). The three sites shared similar RCA protocols but differed in Qb (120-130 vs 150-200 mL/h). Non-RCA circuits were compared with RCA circuits in which the impact of Qb was also assessed.

RESULTS

About 3,981,906 min of circuit pressures were analysed in 2568 circuits in 567 patients. High-Qb RCA was associated with more extreme pressures, and greater AD (IRR 3.7 (1.93-7.08) as well as reduced filter life 21.1 (10.2-42.6) vs 27.0 (14.8-41.6) h). AD in high-Qb RCA circuits was associated with a 49% reduction in filter life, versus 24% reduction in low-Qb RCA, associated with a rise in the rate of increase in transfilter pressure.

CONCLUSIONS

High-Qb RCA-CRRT was associated with greater access dysfunction, earlier filter loss and increased haemodynamic impacts of access dysfunction, suggesting low-Qb RCA-CRRT may improve circuit mechanics, function and longevity.

Development and External Validation of a Model for Predicting Sufficient Filter Lifespan in Anticoagulation-Free Continuous Renal Replacement Therapy Patients

Background

Anticoagulation-free continuous renal replacement therapy (CRRT) was recommended by the current clinical guideline for patients with increased bleeding risk and contraindications of citrate. Nevertheless, anticoagulation-free CRRT yielded heterogeneous filter lifespan. Furthermore, the specific cutoff values for traditional coagulation parameters to predict sufficient filter lifespan of anticoagulation-free CRRT have not yet been determined. The purpose of our present study was to develop and validate a model for predicting sufficient filter lifespan in anticoagulation-free CRRT patients.

Methods

Patients who underwent anticoagulation-free CRRT in our center between June 2013 and June 2019 were retrospectively included. The primary outcome was sufficient filter lifespan (≥24 h). Thirty-seven predictors were included for modeling based on their clinical significance and previous reports. The final model was developed by using multivariable logistic regression analysis and was validated in a separate external cohort.

Results

The development cohort included 170 patients. Sufficient filter lifespan was observed in 80 patients. Thirteen variables were independent predictors for sufficient filter lifespan by logistic regression: body temperature, mean arterial pressure, activated partial thromboplastin time, direct bilirubin, alkaline phosphatase, blood urea nitrogen, vasopressor use, body mass index, white blood cell, platelet count, D-dimer, uric acid, and pH. The area under the curve (AUC) of the stepwise model and internal validation model was 0.82 (95% confidence interval [CI] [0.76–0.88]) and 0.8 (95% CI [0.74–0.87]), respectively. The positive predictive value and the negative predictive value of the stepwise model were 0.77 and 0.79, respectively. The validation cohort included 44 eligible patients and the AUC of the external validation model was 0.82 (95% CI [0.69–0.96]).

Conclusions

The use of a prediction model instead of an assessment based only on coagulation parameters could facilitate the identification of the patients with filter lifespan of ≥24 h when they accepted anticoagulation-free CRRT.

Effect of Dynamic Circuit Pressures Monitoring on the Lifespan of Extracorporeal Circuit and the Efficiency of Solute Removal During Continuous Renal Replacement Therapy

Objective: To observe the effects of dynamic pressure monitoring on the lifespan of the extracorporeal circuit and the efficiency of solute removal during continuous renal replacement therapy (CRRT).

Materials and Methods: A prospective observational study was performed at the West China Hospital of Sichuan University in the ICU. Analyses of the downloaded pressure data recorded by CRRT machines and the solute removal efficiencies, calculated by 2^*Ce/(Cpre+Cpost), where Ce, Cpre, and Cpost are the concentrations of the effluent, pre-filter blood, and post-filter blood, respectively, were performed. Samples were collected at 0, 2, 6, 12, and 24 h when continuous veno-venous hemodiafiltration (CVVHDF) was used after the initiation of CRRT. Measurements in concentrations of creatinine, blood urea nitrogen, and β2-microglobulin in the plasma and effluent were recorded.

Results: Extracorporeal circuits characterized by moderate-to-severe (M–S) access outflow dysfunction (AOD) events, defined as access outflow pressure less than or equal to −200 mmHg for more than 5 min, had shorter median lifespans with no anticoagulation (32.3 vs. 10.90 h, P = 0.001) compared with the no M–S AOD events group. The significant outcome also existed in regional citrate anticoagulation (RCA) (72 vs. 42.47 h, P = 0.02). Moreover, Cox regression analysis revealed that the lack of M–S AOD events, RCA, or CVVHDF independently prolonged the circuit lifespan. All tested solutes removal efficiencies started to decline at 12 h. Furthermore, efficiencies of all solutes removal dropped obviously at 24 h when TMP ≥ 150 mmHg.

Conclusion: RCA and CVVHDF predicted a longer circuit lifespan. M–S AOD events were associated with a shorter circuit lifespan when RCA or no anticoagulant was used. Replacement of extracorporeal circuit could be considered when running time of filter lasted up to 24 h with TMP ≥ 150 mmHg.

Non-pharmacological interventions for preventing clotting of extracorporeal circuits during continuous renal replacement therapy

BACKGROUND

Acute kidney injury (AKI) is a common complication amongst people who are critically ill, and it is associated with an increased risk of death. For people with severe AKI, continuous kidney replacement therapy (CKRT), which is delivered over 24 hours, is needed when they become haemodynamically unstable. When CKRT is interrupted due to clotting of the extracorporeal circuit, the delivered dose is decreased and thus leading to undertreatment.

OBJECTIVES

This review assessed the efficacy of non-pharmacological measures to maintain circuit patency in CKRT.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies up to 25 January 2021 which includes records identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal, and ClinicalTrials.gov.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) (parallel-group and cross-over studies), cluster RCTs and quasi-RCTs that examined non-pharmacological interventions to prevent clotting of extracorporeal circuits during CKRT.  DATA COLLECTION AND ANALYSIS: Three pairs of review authors independently extracted information including participants, interventions/comparators, outcomes, study methods, and risk of bias. The primary outcomes were circuit lifespan and death due to any cause at day 28. We used a random-effects model to perform quantitative synthesis (meta-analysis). We assessed risk of bias in included studies using the Cochrane Collaboration's tool for assessing risk of bias. Summary estimates of effect were obtained using a random-effects model, and results were expressed as risk ratios (RR) and their 95% confidence intervals (CI) for dichotomous outcomes, and mean difference (MD) and 95% CI for continuous outcomes. Confidence in the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach.

MAIN RESULTS

A total of 20 studies involving 1143 randomised participants were included in the review. The methodological quality of the included studies was low, mainly due to the unclear randomisation process and blinding of the intervention. We found evidence on the following 11 comparisons: (i) continuous venovenous haemodialysis (CVVHD) versus continuous venovenous haemofiltration (CVVH) or continuous venovenous haemodiafiltration (CVVHDF); (ii) CVVHDF versus CVVH; (iii) higher blood flow (≥ 250 mL/minute) versus standard blood flow (< 250 mL/minute); (iv) AN69 membrane (AN69ST) versus other membranes; (v) pre-dilution versus post-dilution; (vi) a longer catheter (> 20 cm) placing the tip targeting the right atrium versus a shorter catheter (≤ 20 cm) placing the tip in the superior vena cava; (vii) surface-modified double-lumen catheter versus standard double-lumen catheter with identical geometry and flow design; (viii) single-site infusion anticoagulation versus double-site infusion anticoagulation; (ix) flat plate filter versus hollow fibre filter of the same membrane type; (x) a filter with a larger membrane surface area versus a smaller one; and (xi) a filter with more and shorter hollow fibre versus a standard filter of the same membrane type. Circuit lifespan was reported in 9 comparisons. Low certainty evidence indicated that CVVHDF (versus CVVH: MD 10.15 hours, 95% CI 5.15 to 15.15; 1 study, 62 circuits), pre-dilution haemofiltration (versus post-dilution haemofiltration: MD 9.34 hours, 95% CI -2.60 to 21.29; 2 studies, 47 circuits; I² = 13%), placing the tip of a longer catheter targeting the right atrium (versus placing a shorter catheter targeting the tip in the superior vena cava: MD 6.50 hours, 95% CI 1.48 to 11.52; 1 study, 420 circuits), and surface-modified double-lumen catheter (versus standard double-lumen catheter: MD 16.00 hours, 95% CI 13.49 to 18.51; 1 study, 262 circuits) may prolong circuit lifespan. However, higher blood flow may not increase circuit lifespan (versus standard blood flow: MD 0.64, 95% CI -3.37 to 4.64; 2 studies, 499 circuits; I² = 70%). More and shorter hollow fibre filters (versus standard filters: MD -5.87 hours, 95% CI -10.18 to -1.56; 1 study, 6 circuits) may reduce circuit lifespan. Death from any cause was reported in four comparisons We are uncertain whether CVVHDF versus CVVH, CVVHD versus CVVH or CVVHDF, longer versus a shorter catheter, or surface-modified double-lumen catheters versus standard double-lumen catheters reduced death due to any cause, in very low certainty evidence. Recovery of kidney function was reported in three comparisons. We are uncertain whether CVVHDF versus CVVH, CVVHDF versus CVVH, or surface-modified double-lumen catheters versus standard double-lumen catheters increased recovery of kidney function. Vascular access complications were reported in two comparisons. Low certainty evidence indicated using a longer catheter (versus a shorter catheter: RR 0.40, 95% CI 0.22 to 0.74) may reduce vascular access complications, however the use of surface-modified double lumen catheters versus standard double-lumen catheters may make little or no difference to vascular access complications.

AUTHORS' CONCLUSIONS

The use of CVVHDF as compared with CVVH, pre-dilution haemofiltration, a longer catheter, and surface-modified double-lumen catheter may be useful in prolonging the circuit lifespan, while higher blood flow and more and shorter hollow fibre filter may reduce circuit life. The Overall, the certainty of evidence was assessed to be low to very low due to the small sample size of the included studies. Data from future rigorous and transparent research are much needed in order to fully understand the effects of non-pharmacological interventions in preventing circuit coagulation amongst people with AKI receiving CKRT.

Low Blood Flow Continuous Veno-Venous Haemodialysis Compared with Higher Blood Flow Continuous Veno-Venous Haemodiafiltration: Effect on Alarm Rates, Filter Life, and Azotaemic Control

TITLE

Low blood flow continuous veno-venous haemodialysis (CVVHD) compared with higher blood flow continuous veno-venous haemodiafiltration (CVVHDF): effect on alarm rates, filter life, and azotaemic control.

INTRODUCTION

Continuous renal replacement therapy (CRRT) can be delivered via convective, diffusive, or mixed approaches. Higher blood flows have been advocated for convective clearance efficiency and promotion of filter life. It is unclear whether a lower blood flow predominantly diffusive approach may benefit filter life and alarm rates.

MATERIALS AND METHODS

Sequential cohort study of 284 patients undergoing 874 CRRT circuits from January 2015 to August 2018 in a single university-associated tertiary referral hospital in Australia. Patients underwent a protocol of either CVVHDF at blood flow 200-250 mL/min or CVVHD at blood flow 100-130 mL/min. Machine and patient data were analysed. Outcomes of azotaemic control, filter life, and warning alarm rates were log transformed and analysed with mixed linear modelling with patient as a random effect.

RESULTS

Both groups had similar azotaemic control (effect estimate on log creatinine CVVHD vs. CVVHDF 1.04 [0.87-1.25], p = 0.68) and median filter life (CVVHDF 16.8 [8.4-90.5] h and CVVHD 16.4 [9.4-82.3] h, p = 0.97). However, circuit pressures were less extreme with a narrower distribution during CVVHD. Multivariate analysis showed CVVHD had a reduced risk of warning alarms (incidence risk ratio [IRR] 0.51 [0.38-0.70]) and femoral access placement also had a reduced risk of alarms (IRR 0.55 [0.41-0.73]).

CONCLUSION

Low blood flow CVVHD and femoral vascular access reduce alarms while maintaining azotaemic control and circuit patency thus minimizing bedside clinician workload.

Dose of Continuous Renal Replacement Therapy in Critically Ill Patients: A Bona Fide Quality Indicator

Acute kidney injury (AKI) is common in critically ill patients, and renal replacement therapy (RRT) constitutes an important aspect of acute management during critical illness. Continuous RRT (CRRT) is frequently utilized in intensive care unit settings, particularly in patients with severe AKI, fluid overload, and hemodynamic instability. The main goal of CRRT is to timely optimize solute control, acid-base, and volume status. Total effluent dose of CRRT is a deliverable that depends on multiple factors and therefore should be systematically monitored (prescribed vs. delivered) and iteratively adjusted in a sustainable mode. In this manuscript, we review current evidence of CRRT dosing and provide recommendations for its implementation as a quality indicator of CRRT delivery.

Continuous renal replacement therapy without anticoagulation in critically ill patients at high risk of bleeding: A systematic review and meta-analysis

The current clinical guideline recommends continuous renal replacement therapy (CRRT) proceed without anticoagulation in patients with contraindication to citrate and increased bleeding risk. Nevertheless, the efficacy of anticoagulation-free CRRT remains inconsistent. The purpose of our present systematic review is to evaluate the efficacy and safety of anticoagulant-free CRRT based on the current literatures. The primary outcomes were filter lifespan and risk factors for filter failure. Seventeen observational studies and three randomized controlled trials were included in our present meta-analysis. There was no significant difference in filter lifespan and azotemic control between the anticoagulation-free and systemic heparin group. The regional citrate anticoagulation (RCA) protocol seems to be superior to the anticoagulation-free protocol in terms of filter lifespan (WMD -23.01, 95% CI [-28.62, -17.39], p < 0.001; I²  = 0%, p = 0.53) and azotemic control. Nafamostat protocol could significantly prolong filter lifespan (WMD -8.4, 95% CI [-9.9, -6.9], p < 0.001; I²  = 33.7%, p = 0.21) as compared with anticoagulation-free protocol without better azotemic control. The conventional coagulation parameters showed poor predictive performence for filter failure and the necessity of anticoagulants use before CRRT. Currently, the optimal choice of anticoagulation strategy for critically ill patients with increased bleeding risk could be RCA under close monitoring.

Ensuring Sustainability of Continuous Kidney Replacement Therapy in the Face of Extraordinary Demand: Lessons From the COVID-19 Pandemic

With the exponential surge in patients with coronavirus disease 2019 (COVID-19) worldwide, the resources needed to provide continuous kidney replacement therapy (CKRT) for patients with acute kidney injury or kidney failure may be threatened. This article summarizes subsisting strategies that can be implemented immediately. Pre-emptive weekly multicenter projections of CKRT demand based on evolving COVID-19 epidemiology and routine workload should be made. Corresponding consumables should be quantified and acquired, with diversification of sources from multiple vendors. Supply procurement should be stepped up accordingly so that a several-week stock is amassed, with administrative oversight to prevent disproportionate hoarding by institutions. Consumption of CKRT resources can be made more efficient by optimizing circuit anticoagulation to preserve filters, extending use of each vascular access, lowering blood flows to reduce citrate consumption, moderating the CKRT intensity to conserve fluids, or running accelerated KRT at higher clearance to treat more patients per machine. If logistically feasible, earlier transition to intermittent hemodialysis with online-generated dialysate, or urgent peritoneal dialysis in selected patients, may help reduce CKRT dependency. These measures, coupled to multicenter collaboration and a corresponding increase in trained medical and nursing staffing levels, may avoid downstream rationing of care and save lives during the peak of the pandemic.

Circuit Hemodynamics and Circuit Failure During Continuous Renal Replacement Therapy

OBJECTIVES

To study hemodynamic changes within continuous renal replacement therapy circuits and evaluate their relationship with continuous renal replacement therapy longevity.

DESIGN

Analysis of downloaded variables recorded by continuous renal replacement therapy machines during multiple episodes of clinical care.

SETTING

Tertiary ICU in Melbourne, Australia.

PATIENTS

Cohort of 149 ICU patients: 428 episodes of continuous renal replacement therapy.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Indices of continuous renal replacement therapy function representing 554,991 minutes were assessed including blood flow, access pressure, effluent pressure, prefilter pressure, and return pressure. We defined three patterns of artificial kidney failure: early (≤ 12 hr), intermediate (> 12-24 hr), and late (> 24 hr) in 35%, 31%, and 34% of circuits, respectively. Mean access pressure in late artificial kidney failure was 7.5 mm Hg (7.1-7.9 mm Hg) less negative than early failing circuits and pressures demonstrated lower variability in such late failing circuits. Access dysfunction, defined as access pressure less than or equal to -200 mm Hg occurred in the first 4 hours in 118 circuits (27%) which had a shorter (median [interquartile range]) life at 12.9 hr [5.5-21.3 hr]) hours than access dysfunction-free circuits (18.8 hr [10.1-33.4 hr]; p < 0.0001). Multivariate analysis found the first occurrence of access dysfunction (as a time-varying covariate) was independently associated with increased hazard of subsequent failure (hazard ratio, 1.75; 1.36-2.26). Classification and regression tree analysis of summary pressure indices in the first 2 hours confirmed minimum access pressure to be a significant predictor, as well as indices of transmembrane pressure and return pressure. A pressure-based predictor correctly identified early and late failing circuits (86.2% and 93.6% specificity, respectively).

CONCLUSIONS

Access dysfunction is a predictor of continuous renal replacement therapy circuit failure. Future monitoring of continuous renal replacement therapy hemodynamics may facilitate remedial actions to improve circuit function.

Clinical Survey of Decreased Blood Flow Rate in Continuous Renal Replacement Therapy: A Retrospective Observational Study

Background

Continuous renal replacement therapy (CRRT) is an essential procedure for patients with acute kidney injury in intensive care. It is important to maintain an adequate blood flow rate during CRRT. Several previous studies have reported the relationships between blood flow rate and filter lifespan, or circuit life, in CRRT. Here, we aim at elucidating the incidence and factors associated with a decreased blood flow rate in CRRT.

Methods

This is a retrospective observational study. From January 2014 to June 2017, 119 patients who underwent CRRT in the intensive care unit were enrolled. The definition of a decreased blood flow rate included situations in which the medical staff needed to decrease the blood flow volume. We statistically analyzed the association of the decreased blood flow rate with patients' clinical characteristics.

Results

Of 119 patients, 52 required a decreased blood flow rate during CRRT. Almost half of the cases occurred within one day of starting CRRT. None of the clinical factors (age, sex, height, sequential organ failure assessment (SOFA) score, catheter position, systemic infection, albumin, hemoglobin, and activating coagulation time) were significantly associated with decreased blood flow rate.

Conclusions

A decreased blood flow rate often occurs during CRRT. Clinical factors significantly associated with the occurrence of the decreased blood flow rate were not detected in the current study. Further investigation regarding the occurrence of a decreased blood flow is warranted.

Continuous renal replacement therapy: individualization of the prescription

PURPOSE OF REVIEW

Continuous renal replacement therapy (CRRT) is now the mainstay of renal organ support in the critically ill. As our understanding of CRRT delivery and its impact on patient outcomes improves there is a focus on researching the potential benefits of tailored, patient-specific treatments to meet dynamic needs.

RECENT FINDINGS

The most up-to-date studies investigating aspects of CRRT prescription that can be individualized: CRRT dose, timing, fluid management, membrane selection, anticoagulation and vascular access are reviewed. The use of different doses of CRRT lack conventional high-quality evidence and importantly studies reveal variation in assessment of dose delivery. Research reveals conflicting evidence for clinicians in distinguishing which patients will benefit from 'watchful waiting' vs. early initiation of CRRT. Both dynamic CRRT dosing and precision fluid management using CRRT are difficult to investigate and currently only observational data supports individualization of prescriptions. Similarly, individualization of membrane choice is largely experimental.

SUMMARY

Clinicians have limited evidence to individualize the prescription of CRRT. To develop this, we need to understand the requirements for renal support for individual patients, such as electrolyte imbalance, fluid overload or clearance of systemic inflammatory mediators to allow us to target these abnormalities in appropriately designed randomized trials.