Anticoagulation, delivered dose and outcomes in CRRT: The program to improve care in acute renal disease (PICARD)

Association of anticoagulation use during continuous kidney replacement therapy and 90-day outcomes: A multicentre study

Introduction

Anticoagulation is recommended during continuous kidney replacement therapy (CKRT) to prolong the filter lifespan for optimal filter performance. We aimed to evaluate the effect of anticoagulation during CKRT on dialysis dependence and mortality within 90 days of intensive care unit (ICU) admission.

Method

Our retrospective observational study evaluated the first CKRT session in critically ill adults with acute kidney injury (AKI) in Singapore from April to September 2017. The primary outcome was a composite of dialysis dependence or death within 90 days of ICU admission; the main exposure variable was anticoagulation use (regional citrate anticoagulation [RCA] or systemic heparin). Multivariable logistic regression was performed to adjust for possible confounders: age, female sex, Acute Physiology and Chronic Health Evaluation (APACHE II) score, liver dysfunction, coagulopathy (international normalised ratio[INR] >1.5) and platelet counts of less than 100,000/uL).

Results

The study cohort included 276 patients from 14 participating adult ICUs, of whom 176 (63.8%) experienced dialysis dependence or death within 90 days of ICU admission (19 dialysis dependence, 157 death). Anticoagulation significantly reduced the odds of the primary outcome (adjusted odds ratio [AOR] 0.47, 95% confidence interval [CI] 0.27-0.83, P=0.009). Logistic regression analysis using anticoagulation as a 3-level indicator variable demonstrated that RCA was associated with mortality reduction (AOR 0.46, 95% CI 0.25-0.83, P=0.011), with heparin having a consistent trend (AOR 0.51, 95% CI 0.23-1.14, P=0.102).

Conclusion

Among critically ill patients with AKI, anticoagulation use during CKRT was associated with reduced dialysis or death at 90 days post-ICU admission, which was statistically significant for regional citrate anticoagulation and trended in the same direction of benefit for systemic heparin anticoagulation. Anticoagulation during CKRT should be considered whenever possible.

Analysis of the extracorporeal anticoagulation effect of modified citrate infusion during continuous renal replacement therapy in critically ill patients

INTRODUCTION

To analyze the anticoagulation effect of different local infusion methods of citrate underwent continuous renal replacement therapy (CRRT) in critically ill patients.

METHODS

The study adopted a single-centre retrospective design. Critically ill patients were divided into conventional group and modified group based on the infusion methods of citrate.

RESULTS

The modified group had a longer mean treatment time (67.67 ± 18.69  hours vs. 52.11 ± 24.26 hours, p = 0.007), a lower transmembrane pressure (147.77 ± 66.85 cm H₂ O vs. 200.63 ± 118.66 cm H₂ O, p = 0.038), fewer citrate bag replacements (1.43 ± 0.50 times vs. 10.60 ± 3.19 times, p < 0.001), and more steady ionized calcium at the venous end (0.35 ± 0.06 mmol/L vs. 0.40 ± 0.05 mmol/L, p = 0.006) compared to the conventional group patients, with statistically significant differences. The incidences of citrate accumulation and tubing coagulation were marginally lower in the modified group.

CONCLUSION

The modified local citrate infusion method can prolong treatment time, while reducing both the nursing workload and the occurrence of citrate accumulation.

Regional citrate anticoagulation for replacement therapy in patients with liver failure: A systematic review and meta-analysis

Background

Citrate refers to an anticoagulant agent commonly used in extracorporeal organ support. Its application is limited in patients with liver failure (LF) due to the increased risk of citrate accumulation induced by liver metabolic dysfunction. This systematic review aims to assess the efficacy and safety of regional citrate anticoagulation in extracorporeal circulation for patients with liver failure.

Methods

PubMed, Web of Science, Embase, and Cochrane Library were searched. Studies regarding extracorporeal organ support therapy for LF were included to assess the efficacy and safety of regional citrate anticoagulation. Methodological quality of included studies were assessed using the Methodological Index for Non-randomized Studies (MINORS). Meta-analysis was performed using R software (version 4.2.0).

Results

There were 19 eligible studies included, involving 1026 participants. Random-effect model showed an in-hospital mortality of 42.2% [95%CI (27.2, 57.9)] in LF patients receiving extracorporeal organ support. The during-treatment incidence of filter coagulation, citrate accumulation, and bleeding were 4.4% [95%CI (1.6-8.3)], 6.7% [95%CI (1.5-14.4)], and 5.0% [95%CI (1.9-9.3)], respectively. The total bilirubin(TBIL), alanine transaminase (ALT), aspartate transaminase(AST), serum creatinine(SCr), blood urea nitrogen(BUN), and lactate(LA) decreased, compared with those before the treatment, and the total calcium/ionized calcium ratio, platelet(PLT), activated partial thromboplastin time(APTT), serum potential of hydrogen(pH), buffer base(BB), and base excess(BE) increased.

Conclusion

Regional citrate anticoagulation might be effective and safe in LF extracorporeal organ support. Closely monitoring and timely adjusting during the process could reduce the risk for complications. More prospective clinical trials of considerable quality are needed to further support our findings.

Systematic review registration

https://www.crd.york.ac.uk/prospero/, identifier CRD42022337767.

Regional Citrate Anticoagulation for Continuous Kidney Replacement Therapy With Calcium-Containing Solutions: A Cohort Study

OBJECTIVE

Regional citrate anticoagulation (RCA) is the preferred anticoagulation method for continuous kidney replacement therapy (CKRT) recommended by KDIGO. Limited availability of calcium-free solutions often imposes challenges to the implementation of RCA for CKRT (RCA-CKRT). The principal purpose of this study was to characterize the outcomes of RCA-CKRT using calcium-containing solutions.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

We evaluated the safety and efficacy of RCA-CKRT with calcium-containing dialysate and replacement fluid used for 128 patients. A total of 571 filters and 1,227 days of CKRT were analyzed.

EXPOSURES

Liver disease, sepsis in the absence of liver disease, and sepsis with liver disease.

OUTCOMES

Filter life and metabolic complications per 100 CKRT days.

ANALYTICAL APPROACH

Linear mixed-effects model and generalized linear mixed-effects models.

RESULTS

The majority of patients were male (91; 71.1%), 32 (25%) had liver disease, and 29 (22.7%) had sepsis without liver disease. Median filter life was 50.0 (interquartile range, 22.0-118.0) hours, with a maximum of 322 hours, and was significantly lower (33.5 [interquartile range, 17.5-60.5] h) in patients with liver disease. Calcium-containing replacement solutions were used in 41.6% of all CKRT hours and reduced intravenous calcium requirements by 31.7%. Hypocalcemia (ionized calcium<0.85mmol/L) and hypercalcemia (total calcium>10.6mg/dL) were observed in 6.0 and 6.7 per 100 CKRT days, respectively. Citrate accumulation was observed in 13.3% of all patients and was associated with metabolic acidosis in 3.9%, which was not significantly different in patients with liver disease (9.3%; P = 0.2).

LIMITATIONS

Lack of control groups that used calcium-free dialysate and replacement solutions with RCA-CKRT. Possible overestimation of filter life from incomplete data on cause of filter failure.

CONCLUSIONS

Our study suggests that RCA-CKRT with calcium-containing solutions is feasible and safe in critically ill patients, including those with sepsis and liver disease.

Anticoagulation during Renal Replacement Therapy

How to cite this article: Singh S. Anticoagulation during Renal Replacement Therapy. Indian J Crit Care Med 2020;24(Suppl 3):S112–S116.

Renal replacement therapy: a practical update

Acute kidney injury (AKI) is defined as an abrupt decrease in kidney function, with the most severe form requiring some method of renal replacement therapy (RRT). The use of RRT is required in 5-10% of critically ill patients who develop severe AKI. Renal replacement therapy can be provided as either intermittent hemodialysis or one of the various modes of continuous renal replacement therapy (CRRT), with CRRT potentially conferring an advantage with respect to renal recovery and dialysis independence. There is no difference in mortality when comparing low (< 25 mL·kg^-1·hr^-1) vs high (> 40 mL·kg^-1·hr^-1) RRT dosing. Continuous renal replacement therapy may be run in different modes of increasing complexity depending on a given patient's clinical needs. Regional citrate anticoagulation is recommended as the therapy of choice for the majority of critically ill patients requiring CRRT.

Micro-computed tomography for the quantification of blocked fibers in hemodialyzers

A novel technique based on micro-CT scanning is developed to quantify coagulation in fibers of hemodialyzers. This objectivation is needed to allow accurate assessment of thrombogenicity of dialyzers used during hemodialysis, for example when comparing different strategies to avoid coagulation and/or fiber blocking. The protocol allowed imaging at a resolution of 25 µm, making it possible to count the open, non-coagulated fibers in a non-invasive way. In 3 fresh, non-used FX600 hemodialyzers, patent fiber counts were extremely consistent (10748 ± 2). To illustrate the potential of this technique, different dialysis parameters currently used as surrogates for fiber blocking were evaluated during 20 hemodialysis sessions. After dialysis, the FX600 dialyzers were visually scored for clotting, dried and subsequently weighed and scanned. The number of patent fibers (10003 [8763,10330], range 534–10692) did not correlate with any of the recorded surrogate parameters. Micro-CT scanning is a feasible, objective, non-invasive, accurate and reproducible tool for quantification of the degree of fiber blocking in a hemodialyzer after use, making it a potential gold standard for use in studies on fiber blocking during renal replacement therapies.

Evaluating the safety and efficacy of regional citrate compared to systemic heparin as anticoagulation for continuous renal replacement therapy in critically ill patients: A service evaluation following a change in practice

Following the implementation of citrate anticoagulation for continuous renal replacement therapy, we evaluate its first year of use and compare it to the previously used heparin, to assess whether our patients benefit from the recently reported advantages of citrate. We retrospectively analysed 2 years of data to compare the safety and efficacy of citrate versus heparin. The results have shown that 43 patients received continuous renal replacement therapy with heparin, 37 patients with citrate. We found no significant difference in metabolic control of pH, urea and creatinine after 72 h. Filters anticoagulated with citrate had significantly longer median lifespan (33 h vs 17 h; p = 0.001), shorter downtime (0 h vs 5 h; p = 0.015) and less filter sets per patient day (0.37 vs 0.67; p = 0.002). Filters anticoagulated with heparin were commonly interrupted due to clotting (50% vs 16.4%), whereas filters anticoagulated with citrate were often stopped electively (53.4% vs 24.6%). Patients on heparin filters had significantly higher APPTs, some at potentially dangerous levels (>180 s), whilst patients on citrate filters had significantly higher levels of bicarbonate. Therefore, we conclude that citrate is superior in terms of safety and efficacy, with longer filter lifespan. It has become our first line anticoagulant for continuous renal replacement therapy.

Prolonged Intermittent Renal Replacement Therapy

Prolonged intermittent renal replacement therapy (PIRRT) is becoming an increasingly popular alternative to continuous renal replacement therapy in critically ill patients with acute kidney injury. There are significant practice variations in the provision of PIRRT across institutions, with respect to prescription, technology, and delivery of therapy. Clinical trials have generally demonstrated that PIRRT is non-inferior to continuous renal replacement therapy regarding patient outcomes. PIRRT offers cost-effective renal replacement therapy along with other advantages such as early patient mobilization and decreased nursing time. However, due to lack of standardization of the procedure, PIRRT still poses significant challenges, especially pertaining to appropriate drug dosing. Future guidelines and clinical trials should work toward developing consensus definitions for PIRRT and ensure optimal delivery of therapy.

Renal Replacement Therapy

Renal replacement therapy (RRT) is a cornerstone in the clinical management of patients with acute kidney injury. Results from different studies agree that early renal support therapy (aimed to support the residual kidney function during early phases of organ dysfunction) may reduce mortality with respect to late RRT (aimed to substitute the complete loss of function during the advanced kidney insufficiency). Although it seems plausible that a timely initiation of RRT may be associated with improved renal and nonrenal outcomes in these patients, there is scarce evidence in literature to exactly identify the most adequate onset timing for RRT.

Anticoagulation strategies in venovenous hemodialysis in critically ill patients: a five-year evaluation in a surgical intensive care unit

Renal failure is a common complication among critically ill patients. Timing, dosage, and mode of renal replacement (RRT) are under debate, but also anticoagulation strategies and vascular access interfere with dialysis success. We present a retrospective, five-year evaluation of patients requiring RRT on a multidisciplinary 50-bed surgical intensive care unit of a university hospital with special regard to anticoagulation strategies and vascular access. Anticoagulation was preferably performed with unfractionated heparin or regional citrate application (RAC). Bleeding and suspected HIT-II were most common causes for RAC. In CVVHD mode filter life span was significantly longer under RAC compared to heparin or other anticoagulation strategies (P = 0.001). Femoral vascular access was associated with reduced filter life span (P = 0.012), especially under heparin anticoagulation (P = 0.015). Patients on RAC had higher rates of metabolic alkalosis (P = 0.001), required more transfusions (P = 0.045), and showed higher illness severity measured by SOFA scores (P = 0.001). RRT with unfractionated heparin represented the most common anticoagulation strategy in this study population. However, patients with bleeding risk and severe organ dysfunction were more likely placed on RAC. Citrate provided longer filter life spans regardless of vascular access site. Attention has to be paid to metabolic disturbances.