Continuous venovenous hemodialysis with regional citrate anticoagulation in patients with liver failure: a prospective observational study

Automated regional citrate anticoagulation system based on individualized dosing models in nonliver failure patients undergoing PIRRT therapy

INTRODUCTION

Regional citrate anticoagulation is a preferred option for renal replacement therapy in critically ill patients. However, current implementations ignore individual differences that may exist in the fluctuation of patients' ionized calcium levels. To address this problem, individualized citrate and calcium supplementation models were established based on the pharmacokinetic and clearance characteristics of citrate, and an automated regional citrate anticoagulation system was built with these models as its core to facilitate the treatment of clinical patients. This study was designed to preliminarily evaluate the safety and efficacy of this system, the SuperbMed® RCA-SP100 automated regional citrate anticoagulation system, in prolonged intermittent renal replacement therapy.

METHODS

Seven patients undergoing prolonged intermittent renal replacement therapy completed treatment with the SuperbMed® RCA-SP100 system. In vivo and in vitro ionized calcium levels were measured every hour before and after the start of dialysis. The accuracy and alarm sensitivity of the pumps were also monitored.

RESULTS

During seven treatments, the average extracorporeal ionized calcium level was 0.34 ± 0.02 mmol/L, and the mean ionized calcium level in vivo was 1.09 ± 0.07 mmol/L. No patient required intervention, and there was no filter coagulation. The pumps all had an absolute accuracy less than 5%, and alarms could be triggered precisely.

CONCLUSIONS

We reported on an automated system that allows for individualized citrate and calcium supplementation in prolonged intermittent renal replacement therapy and enables the precise and secure implementation of regional citrate anticoagulation.

Anticoagulation Strategies for Continuous Renal Replacement Therapy in France: A Survey of Practices

INTRODUCTION

Anticoagulation for continuous renal replacement therapy (CRRT) can be performed using systemic anticoagulation or regional citrate anticoagulation (RCA). The 2012 Kidney Disease Improving Global Outcomes guidelines support the use of RCA as the first-line strategy in patients requiring CRRT, with and without bleeding risk. Implementing RCA in the intensive care unit (ICU) implies involving all medical and nursing staff. The primary objective of this study was to report and describe the various anticoagulation strategies for CRRT in French ICUs. The secondary objectives were to determine the rate of RCA use and to identify the factors limiting its implementation.

METHODS

An online questionnaire containing 40 questions was sent to attending physicians and fellows practicing in French ICUs between May and September 2021. The questionnaire was sent via several networks: mailing list from the French Society of Anesthesia and Intensive Care Medicine and mailing lists of RRT manufacturers.

RESULTS

A total of 597 responses were analyzed. RCA was used by most of the participants for patients with (81%) and without (80%) increased bleeding risk. The preferred CRRT modality of the participants while using RCA was continuous veno-venous hemodialysis (48%). The clinical situations frequently reported as an absolute contraindication to RCA were uncontrolled shock associated with liver failure and drug poisoning impairing citrate metabolism (62% and 52%, respectively). In case of a higher risk of citrate accumulation, most participants claimed to perform closer biological monitoring (57%) or to modify the CRRT protocol (61%). Among the participants who did not prescribe RCA as a first-line strategy, the main factors limiting its implementation were the lack of nurse (50%) or physician (34%) training.

CONCLUSION

RCA is the main anticoagulation strategy prescribed for CRRT in France. Providing medical and nursing staff easy access to training may facilitate the understanding and use of RCA as the first-line anticoagulation strategy for CRRT.

Protocolized Regional Citrate Anticoagulation during Continuous Renal Replacement Therapy: A Single Center Experience

Background

Regional citrate anticoagulation (RCA) has emerged as a treatment modality that reduces bleeding risk and filter clotting. With initial experience of using RCA with continuous renal replacement therapy (CRRT), we have formulated a working protocol based on published literature.

Objective

The study aimed to evaluate the protocol for routine use of RCA during CRRT requiring anticoagulation and evaluation of filter life.

Methodology

It is a single-center, open-label, prospective, non-randomized, non-interventional, single-arm, observational study conducted at a tertiary care hospital between September 2022 and July 2023. All adult patients with acute kidney injury (AKI) or hyperammonemia requiring CRRT and necessitating the use of anticoagulation were enrolled in the study. The study used Prisma Flex M100 AN 69 dialyzer on Prisma Flex (Baxter) CRRT machines during continuous venovenous hemodiafiltration (CVVHDF). The targeted CRRT dose in all the study patients was 25-30 mL/kg/hour. Based on the published literature, we have developed a working protocol (Appendix 1) for managing patients on CRRT using RCA.

Results

A total of 159 patients were analyzed for the study. The median [interquartile range (IQR)] filter life using RCA was 30 (12-55) hours. Filter clotting was observed in 33.3% of patients. Citrate accumulation was present in 52.25% of patients, but no CRRT was discontinued as citrate accumulation resolved after following the corrective steps in the protocol. None of the patients had citrate toxicity. Chronic liver disease (CLD) (p ≤ 0.001) and those who were post-living donor liver transplant recipients (p = 0.004) had a statistically significant increase in citrate accumulation. Also, patients who had higher lactate at baseline (6 hours post-CRRT initiation), had a higher chance of citrate accumulation.

Conclusion

Our RCA protocol provides a safe approach to regional anticoagulation during CRRT in critically ill patients.

How to cite this article

Pachisia AV, Kumar GP, Harne R, Jagadeesh KN, Patel SJ, Pal D, et al. Protocolized Regional Citrate Anticoagulation during Continuous Renal Replacement Therapy: A Single Center Experience. Indian J Crit Care Med 2024;28(9):859-865.

How to safeguard the continuous renal replacement therapy circuit: a narrative review

The high prevalence of acute kidney injury (AKI) in ICU patients emphasizes the need to understand factors influencing continuous renal replacement therapy (CRRT) circuit lifespan for optimal outcomes. This review examines key pharmacological interventions-citrate (especially in regional citrate anticoagulation), unfractionated heparin (UFH), low molecular weight heparin (LMWH), and nafamostat mesylate (NM)-and their effects on filter longevity. Citrate shows efficacy with lower bleeding risks, while UFH remains cost-effective, particularly in COVID-19 cases. LMWH is effective but associated with higher bleeding risks. NM is promising for high-bleeding risk scenarios. The review advocates for non-tunneled, non-cuffed temporary catheters, especially bedside-inserted ones, and discusses the advantages of surface-modified dual-lumen catheters. Material composition, such as polysulfone membranes, impacts filter lifespan. The choice of treatment modality, such as Continuous Veno-Venous Hemodialysis (CVVHD) or Continuous Veno-Venous Hemofiltration with Dialysis (CVVHDF), along with the management of effluent volume, blood flow rates, and downtime, are critical in prolonging filter longevity in CRRT. Patient-specific conditions, particularly the type of underlying disease, and the implementation of early mobilization strategies during CRRT are identified as influential factors that can extend the lifespan of CRRT filters. In conclusion, this review offers insights into factors influencing CRRT circuit longevity, supporting evidence-based practices and suggesting further multicenter studies to guide ICU clinical decisions.

APASL clinical practice guidelines on the management of acute kidney injury in acute-on-chronic liver failure

Acute-on-chronic liver failure (ACLF) is a syndrome that is characterized by the rapid development of organ failures predisposing these patients to a high risk of short-term early death. The main causes of organ failure in these patients are bacterial infections and systemic inflammation, both of which can be severe. For the majority of these patients, a prompt liver transplant is still the only effective course of treatment. Kidneys are one of the most frequent extrahepatic organs that are affected in patients with ACLF, since acute kidney injury (AKI) is reported in 22.8-34% of patients with ACLF. Approach and management of kidney injury could improve overall outcomes in these patients. Importantly, patients with ACLF more frequently have stage 3 AKI with a low rate of response to the current treatment modalities. The objective of the present position paper is to critically review and analyze the published data on AKI in ACLF, evolve a consensus, and provide recommendations for early diagnosis, pathophysiology, prevention, and management of AKI in patients with ACLF. In the absence of direct evidence, we propose expert opinions for guidance in managing AKI in this very challenging group of patients and focus on areas of future research. This consensus will be of major importance to all hepatologists, liver transplant surgeons, and intensivists across the globe.

Anticoagulation in renal replacement therapies: Why heparin should be abandoned in critical ill patients?

Extracorporeal circuits used in renal replacement therapy (RRT) can develop thrombosis, leading to downtimes and reduced therapy efficiency. To prevent this, anticoagulation is used, but the optimal anticoagulant has not yet been identified. Heparin is the most widely used anticoagulant in RRT, but it has limitations, such as unpredictable pharmacokinetics, nonspecific binding to plasma proteins and cells, and the possibility of suboptimal anticoagulation or bleeding complications, specifically in critically ill patients with acute renal failure who are already at high risk of bleeding. Citrate anticoagulation is a better alternative, being considered a standard for continuous renal replacement therapy, since it is associated with a lower risk of bleeding complications and better efficacy, even in patients with acute renal failure or liver disease. The aim of this article is to provide an updated review of the different strategies of anticoagulation in renal replacement therapies that can be implemented in critical scenarios, focusing on the advantages and disadvantages of each one and the beneficial aspects of using citrate over heparin in critical ill patients.

A single center retrospective study: Comparison between centrifugal separation plasma exchange with ACD-A and membrane separation plasma exchange with heparin on acute liver failure and acute on chronic liver failure

The purpose of this retrospective study is to compare the efficacy and safety of the centrifugal separation therapeutic plasma exchange (TPE) using citrate anticoagulant (cTPEc) with membrane separation TPE using heparin anticoagulant (mTPEh) in liver failure patients. The patients treated by cTPEc were defined as cTPEc group and those treated by mTPEh were defined as mTPEh group, respectively. Clinical characteristics were compared between the two groups. Survival analyses of two groups and subgroups classified by the model for end-stage liver disease (MELD) score were performed by Kaplan-Meier method and were compared by the log-rank test. In this study, there were 51 patients in cTPEc group and 18 patients in mTPEh group, respectively. The overall 28-day survival rate was 76% (39/51) in cTPEc group and 61% (11/18) in mTPEh group (P > .05). The 90-day survival rate was 69% (35/51) in cTPEc group and 50% (9/18) in mTPEh group (P > .05). MELD score = 30 was the best cut-off value to predict the prognosis of patients with liver failure treated with TPE, in mTPEh group as well as cTPEc group. The median of total calcium/ionized calcium ratio (2.84, range from 2.20 to 3.71) after cTPEc was significantly higher than the ratio (1.97, range from 1.73 to 3.19) before cTPEc (P < .001). However, there was no significant difference between the mean concentrations of total calcium before cTPEc and at 48 h after cTPEc. Our study concludes that there was no statistically significant difference in survival rate and complications between cTPEc and mTPEh groups. The liver failure patients tolerated cTPEc treatment via peripheral vascular access with the prognosis similar to mTPEh. The prognosis in patients with MELD score < 30 was better than in patients with MELD score ≥ 30 in both groups. In this study, the patients with acute liver failure (ALF) and acute on chronic liver failure (ACLF) treated with cTPEc tolerated the TPE frequency of every other day without significant clinical adverse event of hypocalcemia with similar outcomes to the mTPEh treatment. For liver failure patients treated with cTPEc, close clinical observation and monitoring ionized calcium are necessary to ensure the patients' safety.

Regional Citrate Anticoagulation versus No Anticoagulation for CKRT in Patients with Liver Failure with Increased Bleeding Risk

BACKGROUND

The opinions on the efficacy and safety of no anticoagulation versus regional citrate anticoagulation for continuous KRT (CKRT) were controversial in patients with severe liver failure with a higher bleeding risk. We performed a randomized controlled trial to assess no anticoagulation versus regional citrate anticoagulation for CKRT in these patients.

METHODS

Adult patients with liver failure with a higher bleeding risk who required CKRT were considered candidates. The included participants were randomized to receive regional citrate anticoagulation or no-anticoagulation CKRT. The primary end point was filter failure.

RESULTS

Of the included participants, 44 and 45 were randomized to receive regional citrate anticoagulation and no-anticoagulation CKRT, respectively. The no-anticoagulation group had a significantly higher filter failure rate (25 [56%] versus 12 [27%], P = 0.003), which was confirmed by cumulative incidence function analysis and sensitive analysis including only the first CKRT sessions. In the cumulative incidence function analysis, the cumulative filter failure rates at 24, 48, and 72 hours of the no-anticoagulation and regional citrate anticoagulation groups were 31%, 58%, and 76% and 11%, 23%, and 35%, respectively. Participants in the regional citrate anticoagulation group had significantly higher incidences of Ca 2+tot /Ca 2+ion >2.5 (7% versus 57%, P < 0.001), hypocalcemia (51% versus 82%, P = 0.002), and severe hypocalcemia (13% versus 77%, P < 0.001). However, most (73%) of the increased Ca 2+tot /Ca 2+ion ratios were normalized after the upregulation of the calcium substitution rate. In the regional citrate anticoagulation group, there was no significant additional increase in the systemic citrate concentration after 6 hours.

CONCLUSIONS

For patients with liver failure with a higher bleeding risk who required CKRT, regional citrate anticoagulation resulted in significantly longer filter lifespan than no anticoagulation. However, regional citrate anticoagulation in patients with liver failure was associated with a significantly higher risk of hypocalcemia, severe hypocalcemia, and Ca 2+tot /Ca 2+ion >2.5.

CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER

RCA for CRRT in Liver Failure and High Risk Bleeding Patients, NCT03791190 .

Construction and validation of a prediction model for the risk of citrate accumulation in patients with hepatic insufficiency receiving continuous renal replacement therapy with citrate anticoagulation

BACKGROUND

To construct and validate a prediction model of the risk of citrate accumulation in patients with hepatic dysfunction receiving continuous renal replacement therapy with regional citrate anticoagulation (RCA-CRRT), which reduces the risk of citrate accumulation.

METHODS

All patients who received RCA-CRRT from 2021 to 2022 and were hospitalized in the First Affiliated Hospital of Zhejiang University were considered for study participation. Logistic regression analysis was used to identify the risk factors for citrate accumulation, based on which a nomogram model was constructed and validated in the validation group.

RESULTS

Six factors were finally identified, from which a nomogram was created to predict the risk of citrate accumulation. The area under the curve of the prediction model was 0.814 in the training group and 0.819 in the validation group, and the model showed acceptable agreement between the actual and predicted probabilities. Decision curve analysis also demonstrated that the model was clinically useful.

CONCLUSIONS

The model constructed from six factors reliably predicted the risk of citrate accumulation in patients with hepatic insufficiency who received RCA-CRRT.

Navigating the Labyrinth: Intensive Care Challenges for Patients with Acute-on-Chronic Liver Failure

Acute-on-chronic liver failure (ACLF) refers to the deterioration of liver function in individuals who already have chronic liver disease. In the setting of ACLF, liver damage leads to the failure of other organs and is associated with increased short-term mortality. Optimal medical management of patients with ACLF requires implementing complex treatment strategies, often in an intensive care unit (ICU). Failure of organs other than the liver distinguishes ACLF from other critical illnesses. Although there is growing evidence supporting the current approach to ACLF management, the mortality associated with this condition remains unacceptably high. In this review, we discuss considerations for ICU care of patients with ACLF and highlight areas for further research.

Hypercitratemia is a mortality predictor among patients on continuous venovenous hemodiafiltration and regional citrate anticoagulation

The use of regional citrate anticoagulation (RCA) in liver failure (LF) patients can lead to citrate accumulation. We aimed to evaluate serum levels of citrate and correlate them with liver function markers and with the Cat/Cai in patients under intensive care and undergoing continuous venovenous hemodiafiltration with regional citrate anticoagulation (CVVHDF-RCA). A prospective cohort study in an intensive care unit was conducted. We compared survival, clinical, laboratorial and dialysis data between patients with and without LF. Citrate was measured daily. We evaluated 200 patients, 62 (31%) with LF. Citrate was significantly higher in the LF group. Dialysis dose, filter lifespan, systemic ionized calcium and Cat/Cai were similar between groups. There were weak to moderate positive correlations between Citrate and indicators of liver function and Cat/Cai. The LF group had higher mortality (70.5% vs. 51.8%, p = 0.014). Citrate was an independent risk factor for death, OR 11.3 (95% CI 2.74-46.8). In conclusion, hypercitratemia was an independent risk factor for death in individuals undergoing CVVHDF-ARC. The increase in citrate was limited in the LF group, without clinical significance. The correlation between citrate and liver function indicators was weak to moderate.

Simplified regional citrate anticoagulation protocol for CVVH, CVVHDF and SLED focused on the prevention of KRT-related hypophosphatemia while optimizing acid-base balance

BACKGROUND

Hypophosphatemia is a common electrolyte disorder in critically ill patients undergoing prolonged kidney replacement therapy (KRT). We evaluated the efficacy and safety of a simplified regional citrate anticoagulation (RCA) protocol for continuous venovenous hemofiltration (CVVH), continuous venovenous hemodiafiltration (CVVHDF) and sustained low-efficiency dialysis filtration (SLED-f). We aimed at preventing KRT-related hypophosphatemia while optimizing acid-base equilibrium.

METHODS

KRT was performed by the Prismax system (Baxter) and polyacrylonitrile AN69 filters (ST 150, 1.5 m2, Baxter), combining a 18 mmol/L pre-dilution citrate solution (Regiocit 18/0, Baxter) with a phosphate-containing solution (HPO42- 1.0 mmol/L, HCO3- 22.0 mmol/L; Biphozyl, Baxter). When needed, phosphate loss was replaced with sodium glycerophosphate pentahydrate (Glycophos™ 20 mmol/20 mL, Fresenius Kabi Norge AS, Halden, Norway). Serum citrate measurements were scheduled during each treatment. We analyzed data from three consecutive daily 8-h SLED-f sessions, as well as single 72-h CVVH or 72-h CVVHDF sessions. We used analysis of variance (ANOVA) for repeated measures to evaluate differences in variables means (i.e. serum phosphate, citrate). Because some patients received phosphate supplementation, we performed analysis of covariance (ANCOVA) for repeated measures modelling phosphate supplementation as a covariate.

RESULTS

Forty-seven patients with acute kidney injury (AKI) or end stage kidney disease (ESKD) requiring KRT were included [11 CVVH, 11 CVVHDF and 25 SLED-f sessions; mean Acute Physiology and Chronic Health Evaluation II (APACHE II) score 25 ± 7.0]. Interruptions for irreversible filter clotting were negligible. The overall incidence of hypophosphatemia (s-P levels <2.5 mg/dL) was 6.6%, and s-P levels were kept in the normality range irrespective of baseline values and the KRT modality. The acid-base balance was preserved, with no episode of citrate accumulation.

CONCLUSIONS

Our data obtained with a new simplified RCA protocol suggest that it is effective and safe for CVVH, CVVHDF and SLED, allowing to prevent KRT-related hypophosphatemia and maintain the acid-base balance without citrate accumulation.

TRIAL REGISTRATION

NCT03976440 (registered 6 June 2019).

Calcium-Citrate Anticoagulation during Continuous Renal Replacement Therapy in Patients with Metformin Intoxication: A Case Series, Mathematical Estimation of Citrate Accumulation, and Literature Review

INTRODUCTION

Metformin intoxication causes lactic acidosis by inhibiting Krebs' cycle and oxidative phosphorylation. Continuous renal replacement therapy (CRRT) is recommended for metformin removal in critically ill patients. According to current guidelines, regional citrate anticoagulation (RCA) is the first-line strategy. However, since metformin also inhibits citrate metabolism, a risk of citrate accumulation could be hypothesized. In the present study, we monitored the potential citrate accumulation in metformin-associated lactic acidosis (MALA) patients treated with CRRT and RCA using the physical-chemical approach to acid-base interpretation.

METHODS

We collected a case series of 3 patients with MALA. Patients were treated with continuous venovenous hemofiltration (CVVH), and RCA was performed with diluted citrate solution. Citrate accumulation was monitored through two methods: the ratio between total and ionized plasma calcium concentrations (T/I calcium ratio) above 2.5 and the strong ion gap (SIG) to identify an increased concentration of unmeasured anions. Lastly, a mathematical model was developed to estimate the expected citrate accumulation during CVVH and RCA.

RESULTS

All 3 patients showed a resolution of MALA after the treatment with CVVH. The T/I calcium ratio was consistently below 2.5, and SIG decreased, reaching values lower than 6 mEq/L after 48 h of CVVH treatment. According to the mathematical model, the estimated SIG without citrate metabolism should have been around 21 mEq/L due to citrate accumulation.

CONCLUSIONS

In our clinical management, no signs of citrate accumulation were recorded in MALA patients during treatment with CVVH and RCA. Our data support the safe use of diluted citrate to perform RCA during metformin intoxication.

Safety of Citrate Anticoagulation in CKRT: Monocentric Experience of a Dynamic Protocol of Calcium Monitoring

Regional Citrate Anticoagulation (RCA) is considered the first-line anticoagulation for Continuous Kidney Replacement Therapy (CKRT). The RCA requires strict protocols and trained staff to avoid unsafe use and ensure its benefit. We have analyzed all our CKRT prescriptions from December 2020 to April 2022 anonymously, collecting data on CKRT, lab tests, clinical conditions, and complications of RCA. In addition, in order to better detect citrate accumulation, we have performed an RCA protocol by reducing the CaTot/Ca2+ ratio cut-off from 2.50 to 2.40 and increasing the number of calcium checks according to its trend. Among the 374 patients in CKRT, 104 received RCA prescriptions, of which 11 (10.6%) were discontinued: 4 for the suspicion of citrate accumulation, 1 for the development of metabolic alkalosis, 1 for the shift to a different CKRT procedure due to the need for a higher bicarbonate dose, 4 for the elevation of hepatocytolysis indexes, and 1 due to a preemptive discontinuation following massive post-surgery bleeding. None of the patients have had citrate toxicity as indicated by a CaTot/Ca2+ greater than 2.50, and our protocol has allowed the early identification of patients who might develop clinical citrate toxicity.

Novel blood product transfusion regimen to prevent clotting and citrate accumulation during continuous renal replacement therapy with regional citrate anticoagulation in children

Objective

Introduce a novel protocol to prevent clotting and citrate accumulation (CA) from blood product transfusion (BPT) during continuous renal replacement therapy (CRRT) with regional citrate anticoagulation (RCA) in children.

Methods

We prospectively compared fresh frozen plasma (FFP) and platelet transfusions between the two BPT protocols, direct transfusion protocol (DTP) and partial replacement of citrate transfusion protocol (PRCTP), in terms of the risks of clotting, citric accumulation (CA), and hypocalcemia. For DTP, blood products were directly transfused without any adjustment to the original RCA-CRRT regimen. For PRCTP, the blood products were infused into the CRRT circulation near the sodium citrate infusion point, and the dosage of 4% sodium citrate was reduced depending on the dosage of sodium citrate in the blood products. Basic information and clinical data were recorded for all children. Heart rate, blood pressure, ionized calcium (iCa) and various pressure parameters were recorded before, during and after BPT, as well as coagulation indicators, electrolytes, and blood cell counts before and after BPT.

Results

Twenty-six children received 44 PRCTPs and 15 children received 20 DTPs. The two groups had similar in vitro ionized calcium (iCa) concentrations (PRCTP: 0.33 ± 0.06 mmol/L, DTP: 0.31 ± 0.04 mmol/L), total filter lifespan (PRCTP: 49.33 ± 18.58, DTP: 50.65 ± 13.57 h), and filter lifespan after BPT (PRCTP: 25.31 ± 13.87, DTP: 23.39 ± 11.34 h). There was no visible filter clotting during BPT in any of the two groups. The two groups had no significant differences in arterial pressure, venous pressure, and transmembrane pressure before, during, or after BPT. Neither treatment led to significant decreases in WBC, RBC, or hemoglobin. The platelet transfusion group and the FFP group each had no significant decrease in platelets, and no significant increases in PT, APTT, and D-dimer. The most clinically significant changes were in the DTP group, in which the ratio of total calcium to ionized calcium (T/iCa) increased from 2.06 ± 0.19 to 2.52 ± 0.35, the percentage of patients with T/iCa above 2.5 increased from 5.0% to 45%, and the level of in vivo iCa increased from 1.02 ± 0.11 to 1.06 ± 0.09 mmol/L (all p < 0.05). Changes in these three indicators were not significant in the PRCTP group.

Conclusion

Neither protocol was associated with filter clotting during RCA-CRRT. However, PRCTP was superior to DTP because it did not increase the risk of CA and hypocalcemia.

Management of regional citrate anticoagulation for continuous renal replacement therapy: guideline recommendations from Chinese emergency medical doctor consensus

Continuous renal replacement therapy (CRRT) is widely used for treating critically-ill patients in the emergency department in China. Anticoagulant therapy is needed to prevent clotting in the extracorporeal circulation during CRRT. Regional citrate anticoagulation (RCA) has been shown to potentially be safer and more effective and is now recommended as the preferred anticoagulant method for CRRT. However, there is still a lack of unified standards for RCA management in the world, and there are many problems in using this method in clinical practice. The Emergency Medical Doctor Branch of the Chinese Medical Doctor Association (CMDA) organized a panel of domestic emergency medicine experts and international experts of CRRT to discuss RCA-related issues, including the advantages and disadvantages of RCA in CRRT anticoagulation, the principle of RCA, parameter settings for RCA, monitoring of RCA (mainly metabolic acid-base disorders), and special issues during RCA. Based on the latest available research evidence as well as the paneled experts' clinical experience, considering the generalizability, suitability, and potential resource utilization, while also balancing clinical advantages and disadvantages, a total of 16 guideline recommendations were formed from the experts' consensus.

Evaluation of the registry DIALYREG for the assessment of continuous renal replacement techniques in the critically ill patient

Continuous renal replacement techniques (CRRT) can induce complications and monitoring is crucial to ensure patient safety. We designed a prospective multicenter observational and descriptive study using the DIALYREG registry, an online database located on a REDCap web-based platform that allows real-time data analysis. Our main objective was to identify CRRT-related complications in our intensive care units (ICUs) and implement security measures accordingly. From January 2019 to December 2020, we included 323 patients with admission diagnoses of medical illness (54%), sepsis (24%), postoperative care (20%), and trauma (2%). CRRT indications were homeostasis (42%), oliguria (26%), fluid overload (15%), and hemodynamic optimization (13%). The median initial therapy dose was 30 ml/kg/h (IQR 25-40), and dynamic adjustment was performed in 61% of the treatments. Sets were anticoagulated with heparin (40%), citrate (38%) or no anticoagulation (22%). Citrate anticoagulation had several advantages: more frequent dynamic CRRT dose adjustment (77% vs. 58% with heparin and 56% without anticoagulation, p < 0.05), longer duration of set (median of 55 h, IQR 24-72 vs. 23 h, IQR 12-48 with heparin and 12 h, IQR 12-31 without anticoagulation, p < 0.05), less clotting of the set (26% vs. 46.7% with heparin, p < 0.05), and lower incidence of hypophosphatemia (1% citrate vs. 6% with heparin and 5% without anticoagulation). It was also safe and effective in subgroup analysis of patients with liver disease or sepsis. The main global complications were hypothermia (16%), hypophosphatemia (13%) and metabolic acidosis (10%). Weaning of the therapy was achieved through early discontinuation (56%), nocturnal therapy transition (26%) and progressive SLED (18%). 52% of the patients were discharged from the hospital, while 43% died in the ICU and 5% died during hospitalization. We can conclude that the DIALYREG registry is a feasible tool for real-time control of CRRT in our ICU.

Regional citrate anticoagulation (RCA) in critically ill patients undergoing renal replacement therapy (RRT): expert opinion from the SIAARTI-SIN joint commission

Renal replacement therapies (RRT) are essential to support critically ill patients with severe acute kidney injury (AKI), providing control of solutes, fluid balance and acid-base status. To maintain the patency of the extracorporeal circuit, minimizing downtime periods and blood losses due to filter clotting, an effective anticoagulation strategy is required.Regional citrate anticoagulation (RCA) has been introduced in clinical practice for continuous RRT (CRRT) in the early 1990s and has had a progressively wider acceptance in parallel to the development of simplified systems and safe protocols. Main guidelines on AKI support the use of RCA as the first line anticoagulation strategy during CRRT in patients without contraindications to citrate and regardless of the patient's bleeding risk.Experts from the SIAARTI-SIN joint commission have prepared this position statement which discusses the use of RCA in different RRT modalities also in combination with other extracorporeal organ support systems. Furthermore, advise is provided on potential limitations to the use of RCA in high-risk patients with particular attention to the need for a rigorous monitoring in complex clinical settings. Finally, the main findings about the prospective of optimization of RRT solutions aimed at preventing electrolyte derangements during RCA are discussed in detail.

Pharmacological methods for blood stabilization in the extracorporeal circuit (review of literature)

We summarize the possible benefits and risks of using various anticoagulants during hemoperfusion. Clotting in the extracorporeal circuit can lead to a decrease in the effectiveness of therapy,  additional workload,  risk to the patient and economic losses. At the same time, relatively excessive anticoagulation against the background of existing hemostasis  disorders  can lead to severe hemorrhagic complications, which in turn  worsen the prognosis of patients. The article describes the causes of heparin resistance, the main techniques for overcoming it, and provides practical guidelines for anticoagulant therapy during hemoperfusion. It is well known that routine methods of monitoring hemostasis (such as platelet count, activated partial thromboplastin time) are unable to assess the balance of pro/anticoagulants. The authors have proposed a reasonable personalized approach to anticoagulant therapy  of extracorporeal blood purification depending  on the pathology  in patient and thromboelastography (TEG) data, and antithrombin III levels.

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 or Heparin Anticoagulation for Renal Replacement Therapy in Patients With Liver Failure: A Systematic Review and Meta-Analysis

In patients with liver failure complicated by acute kidney injury, renal replacement therapy (RRT) is often required to improve the internal environment. The use of anticoagulants for RRT in patients with liver failure remains controversial. We searched the PubMed, Embase, Cochrane Library, and Web of Science databases for studies. The methodological quality of the included studies was assessed using the Methodological Index for Nonrandomized Studies. A meta-analysis was performed using R software (version 3.5.1) and Review Manager (version 5.3.5). During RRT, 348 patients from 9 studies received regional citrate anticoagulation (RCA), and 127 patients from 5 studies received heparin anticoagulation (including heparin and LMWH). Among patients who received RCA, the incidence of citrate accumulation, metabolic acidosis, and metabolic alkalosis were 5.3% (95% confidence interval [CI]: 0%-25.3%), 26.4% (95% CI: 0-76.9), and 1.8% (95% CI: 0-6.8), respectively. The potassium, phosphorus, total bilirubin (TBIL), and creatinine levels were lower, whereas the serum pH, bicarbonate, base excess levels, and total calcium/ionized calcium ratio were higher after treatment than before treatment. Among patients who received heparin anticoagulation, the TBIL levels were lower, whereas the activated partial thromboplastin clotting time and D-dimer levels were higher after treatment than before treatment. The mortality rates in the RCA and heparin anticoagulation groups were 58.9% (95% CI: 39.2-77.3) and 47.4% (95% CI: 31.1-63.7), respectively. No statistical difference in mortality was observed between the 2 groups. For patients with liver failure, the administration of RCA or heparin for anticoagulation during RRT under strict monitoring may be safe and effective.

Comparison of nafamostat mesilate to citrate anticoagulation in pediatric continuous kidney replacement therapy

BACKGROUND

Regional citrate anticoagulation (RCA) is the preferred continuous kidney replacement therapy (CKRT) anticoagulation strategy for children in the USA. Nafamostat mesilate (NM), a synthetic serine protease, is used widely for CKRT anticoagulation in Japan and Korea. We compared the safety and efficacy of NM to RCA for pediatric CKRT.

METHODS

Starting June 2019, the most recent 100 medical records of children receiving CKRT with either RCA or NM were reviewed retrospectively, at one children's hospital in Japan (NM) and one in the USA (RCA). The number of hours a single CKRT filter was in use, was the primary outcome. Safety was assessed by bleeding complications for the NM group and citrate toxicity leading to RCA discontinuation or electrolyte imbalance in the RCA group.

RESULTS

Eighty patients received NM and 78 patients received RCA. Median filter life was longer for the NM group (NM: 38 [22, 74] vs. RCA: 36 [17, 66] h, p = 0.02). When filter life was censored for discontinuation other than clotting, the 60-h survival rate was higher for RCA (71% vs. 54%). The hazard ratio comparing NM over RCA varied over time (HR 0.7; 0.2-1.5, p = 0.33 at 0 h to HR 5.5; 1.3-23.7, p = 0.334 at 72 h). The lack of difference in filter survival persisted controlling for filter surface area, catheter diameter, and pre-CKRT platelet count. Major bleeding rates did not differ between groups (NM: 5% vs. RCA: 9%).

CONCLUSIONS

RCA and NM provide satisfactory anticoagulation for CKRT in children with no difference in major bleeding rates. A higher resolution version of the Graphical abstract is available as Supplementary information.

Management of hepatorenal syndrome in liver cirrhosis: a recent update

Hepatorenal syndrome (HRS) is a serious form of renal dysfunction in patients with cirrhosis and ascites. It is an important component of the acute-on-chronic liver failure (ACLF) syndrome. Significant recent changes in the understanding of the pathophysiology of renal dysfunction in cirrhosis include the role of inflammation in addition to hemodynamic changes. The term acute kidney injury (AKI) is now adopted to include all functional and structural forms of acute renal dysfunction in cirrhosis, with various stages describing the severity of the condition. Type 1 hepatorenal syndrome (HRS1) is renamed HRS-AKI, which is stage 2 AKI [doubling of baseline serum creatinine (sCr)] while fulfilling all other criteria of HRS1. Albumin is used for its volume expanding and anti-inflammatory properties to confirm the diagnosis of HRS-AKI. Vasoconstrictors are added to albumin as pharmacotherapy to improve the hemodynamics. Terlipressin, although not yet available in North America, is the most common vasoconstrictor used worldwide. Patients with high grade of ACLF treated with terlipressin are at risk for respiratory failure if there is pretreatment respiratory compromise. Norepinephrine is equally effective as terlipressin in reversing HRS1. Recent data show that norepinephrine may be administered outside the intensive care setting, but close monitoring is still required. There has been no improvement in overall or transplant-free survival shown with vasoconstrictor use, but response to vasoconstrictors with reduction in sCr is associated with improvement in survival. Non-responders to vasoconstrictor plus albumin will need liver transplantation as definite treatment with renal replacement therapy as a bridge therapy. Combined liver and kidney transplantation is recommended for patients with prolonged history of AKI, underlying chronic kidney disease or with hereditary renal conditions. Future developments, such as the use of biomarkers and metabolomics, may help to identify at risk patients with earlier diagnosis to allow for earlier treatment with improved outcomes.

Continuous Renal Replacement Therapy with Regional Citrate Anticoagulation in Children with Liver Dysfunction/Failure

Regional citrate anticoagulation (RCA) is an option but citrate accumulation is risk and it is a giving up cause for this situation. This retrospective study was conducted in the pediatric intensive care unit (PICU) between May 2019 and April 2021. We investigated 47 patients with liver failure (LF) in our PICU, and RCA during continuous renal replacement therapy (CRRT) was applied to 10 (21.3%) of them. Half of them were male (n: 5/10), their mean age was 104.7 ± 66.20 months. Nine of them needed vasoactive support during follow-up. The most common indication for CRRT was hepatorenal syndrome (40%). There was no significant difference between liver transaminases and liver function tests before and after CRRT (p > 0.05). In terms of citrate toxicity of the patients, there was no significant difference between total calcium/ionized calcium, lactate level, pH and bicarbonate values before and after CRRT (p > 0.05). The mean total CRRT time was 110.2 ± 118.2 h, and the mean circuit lifespan was 43.8 ± 48.7 h; the mean number of circuits was 2.7 ± 2.4. Total Ca/ionized Ca >2.5 was a clinically relevant endpoint, but no patient interrupted dialysis for this cause. There was no complication about RCA. This study did not observe any adverse effects on acid-base status, transaminases, an increase in bilirubin during RCA-CRRT treatment in pediatric patients with LF. Total calcium/ionized calcium ratio, serum lactate level and prothrombin time level should be closely monitored daily in terms of citrate accumulation in this patient group.

Citrate pharmacokinetics in critically ill liver failure patients receiving CRRT

Citrate has been proposed as anticoagulation of choice in continuous renal replacement therapy (CRRT). However, little is known about the pharmacokinetics (PK) and metabolism of citrate in liver failure patients who require CRRT with regional citrate anticoagulation (RCA). This prospective clinical PK study was conducted at King Chulalongkorn Memorial Hospital between July 2019 to April 2021, evaluating seven acute liver failure (ALF) and seven acute-on-chronic liver failure (ACLF) patients who received CRRT support utilizing RCA as an anticoagulant at a citrate dose of 3 mmol/L. For evaluation of the citrate PK, we delivered citrate for 120 min and then stopped for a further 120 min. Total body clearance of citrate was 152.5 ± 50.9 and 195.6 ± 174.3 mL/min in ALF and ACLF, respectively. The ionized calcium, ionized magnesium, and pH slightly decreased after starting citrate infusion and gradually increased to baseline after stopping citrate infusion. Two of the ACLF patients displayed citrate toxicity during citrate infusion, while, no ALF patient had citrate toxicity. In summary, citrate clearance was significantly decreased in critically ill ALF and ACLF patients receiving CRRT. Citrate use as an anticoagulation in these patients is of concern for the risk of citrate toxicity.

Management of acute renal replacement therapy in critically ill cirrhotic patients

Renal replacement therapy (RRT) in cirrhotic patients encompasses a number of issues related to the particular characteristics of this population, especially in the intensive care unit (ICU) setting. The short-term prognosis of cirrhotic patients with acute kidney injury is poor, with a mortality rate higher than 65% in patients with RRT requirement, raising questions about the futility of its initiation. Regarding the management of the RRT itself, there is still no consensus with respect to the modality (continuous versus intermittent) or the anticoagulation required to improve the circuit life, which is shorter than similar at-risk populations, despite the altered haemostasis in traditional coagulation tests frequently found in these patients. Furthermore, volume management is one of the most complex issues in this cohort, where tools used for ambulatory dialysis have not yet been successfully reproducible in the ICU setting. This review attempts to shed light on the management of acute RRT in the critically ill cirrhotic population based on the current evidence and the newly available tools. We will discuss the timing of RRT initiation and cessation, the modality, anticoagulation and fluid management, as well as the outcomes of the RRT in this population, and provide a brief review of the albumin extracorporeal dialysis from the point of view of a nephrologist.

Clinical application of regional citrate anticoagulation for continuous renal replacement therapy in children with liver injury

BACKGROUND

Regional citrate anticoagulation (RCA) is increasingly used for continuous renal replacement therapy (CRRT) in children, but it is rarely used in children with liver injury, especially liver failure (LF). We analyze this issue through the following research.

METHODS

We retrospectively analyzed 75 children with liver injury who underwent RCA-CRRT in the Pediatric Intensive Care Unit (PICU) of Children's Hospital of Chongqing Medical University. The patients were divided into the LF group and liver dysfunction (LD) group. The two groups were compared to evaluate the clinical safety and efficacy of RCA-CRRT in children with liver injury and to explore RCA-CRRT management strategies, in terms of the following indicators: the incidence of bleeding, clotting, citrate accumulation (CA), acid-base imbalance, and electrolyte disturbance, as well as filter lifespans, changes in biochemical indicators, and CRRT parameters adjustment.

RESULTS

The total incidence of CA (TCA) and persistent CA (PCA) in the LF group were significantly higher than those in the LD group (38.6 vs. 16.2%, p < 0.001; 8.4 vs. 1.5%, p < 0.001); and the CA incidence was significantly reduced after adjustment both in the LF (38.6 vs. 8.4%, p < 0.001) and LD groups (16.2 vs. 1.5%, p < 0.001). The incidence of hypocalcemia was significantly higher in the LF group than in the LD group either before (34.9 vs. 8.8%, p < 0.001) or after treatment (12.0 vs. 0%, p < 0.001). The speed of the blood and citrate pumps after adjustment was lower than the initial setting values in both the LF and LD groups. The dialysis speed plus replacement speed were higher than the initial settings parameters.

CONCLUSION

For children undergoing RCA-CRRT, the risks of CA and hypocalcemia are significantly higher in children with liver failure than those with liver dysfunction, but through the proper adjustment of the protocol, RCA-CRRT can still be safely and effectively approached for children with LD and even LF.

Heparin-free regional anticoagulation of haemodialysis filters with calcium-free dialysate: is citrate mandatory?

Background

There is an unmet need to develop safe and successful heparin-free regional anticoagulation modalities in haemodialysed patients at risk of bleeding. Whether the addition of citrate as a prefilter injection or in the dialysate itself is required to reach anticoagulation objectives when calcium-free dialysate is used as regional anticoagulation remains unclear.

Methods

In this monocentric retrospective study, we report our experience of 908 dialysis sessions performed with a calcium-free citrate-containing dialysate and calcium reinjection according to the ionic dialysance, without additional heparin.

Results

Premature termination for filter clotting occurred in 20 sessions (2.2%) and duration of session was >4.5 h in 135 (15%; maximum duration 6 h). In addition, we could investigate the citrate, calcium and acid–basis status during haemodialysis sessions performed with (citrate group, n = 20 sessions) or without (citrate-free group, n = 19 sessions) citrate in the dialysate. In 20 sessions performed in patients with underlying liver disorders and using calcium-free citrate-containing dialysate, patients’ ionized calcium (iCa) and serum citrate levels were stable and remained within the normal range, respectively. Post-filter iCa was below 0.4 mmol/L in 19/20 sessions and citrate was 0.304 mmol/L (range: 0.011; 0.548). In 19 sessions that used calcium and citrate-free dialysate, post-filter iCa was 0.41 mmol/L (0.34; 0.5) and all sessions extended to 4 h or beyond.

Conclusions

Regional anticoagulation of haemodialysis with a calcium-free dialysate and calcium reinjection according to the ionic dialysance is safe. Adding citrate to the dialysate is not mandatory to prevent dialysis circuit clotting in most patients.

Development of a Multivariable Prediction Model for Citrate Accumulation in Liver Transplant Patients Undergoing Continuous Renal Replacement Therapy with Regional Citrate Anticoagulation

INTRODUCTION

Patients with impaired citrate metabolism may experience citrate accumulation (CA), which causes life-threatening metabolic acidosis and hypocalcemia. CA poses a challenge for clinicians when deciding on the use of regional citrate anticoagulation (RCA) for patients with liver dysfunction. This study aimed to develop a prediction model integrating multiple clinical variables to assess the risk of CA in liver transplant patients.

METHODS

This single-center prospective cohort study included postoperative liver transplant patients who underwent continuous renal replacement therapy (CRRT) with RCA. The study end point was CA. A prediction model was developed using a generalized linear mixed-effect model based on the Akaike information criterion. The predictive values were assessed using the receiver operating characteristic curve and bootstrap resampling (times = 500) to estimate the area under the curve (AUC) and the corresponding 95% confidence interval (CI). A nomogram was used to visualize the model.

RESULTS

This study included 32 patients who underwent 133 CRRT sessions with RCA. CA occurred in 46 CRRT sessions. The model included lactate, norepinephrine >0.1 μg/kg/min, alanine aminotransferase, total bilirubin, and standard bicarbonate, which were tested before starting each CRRT session and body mass index, diabetes mellitus, and chronic kidney disease as predictors. The AUC of the model was 0.867 (95% CI 0.786-0.921), which was significantly higher than that of the single predictor (p < 0.05). A nomogram visualized the prediction model.

CONCLUSIONS

The prediction model integrating multiple clinical variables showed a good predictive value for CA. A nomogram visualized the model for easy application in clinical practice.

Extracorporeal renal and liver support in pediatric acute liver failure

The liver is the only organ which can regenerate and, thus, potentially negate the need for transplantation in acute liver failure (ALF). Cerebral edema and sepsis are leading causes of mortality in ALF. Both water-soluble and protein-bound toxins have been implicated in pathogenesis of various ALF complications. Ammonia is a surrogate marker of water-soluble toxin accumulation in ALF and high levels are associated with higher grades of hepatic encephalopathy, raised intracranial pressure, and mortality. Therefore, extracorporeal therapies aim to lower ammonia and maintain fluid balance and cytokine homeostasis. The most common and easily available modality is continuous kidney replacement therapy (CKRT). Early initiation of high-volume CKRT utilizing an anticoagulation regimen minimizing treatment downtime and delivering the prescribed dose is highly desirable. Ideally, extracorporeal liver-assist devices (ECLAD) should perform both synthetic and detoxification functions of the liver. ECLAD may temporarily replace lost liver function and serve as a bridge, either to spontaneous recovery or liver transplantation. Various bioartificial and biologic liver-assist devices are described in specialty literature, including molecular adsorbent recirculating system (MARS), single pass albumin dialysis (SPAD), and total plasma exchange (TPE); however, clinicians commonly use modalities easily available in intensive care units. There is a lack of standardization of indications for ECLAD, availability of different extracorporeal devices with varied technical approaches, and, of note, the differences in doses of ECLAD provided in clinical practice. We review the practicalities and evidence regarding these four artificial liver support devices in pediatric ALF.

A simplified protocol for individualized regional citrate anticoagulation for hemodialysis: A single-center, randomized clinical study

INTRODUCTION

The lack of individualized treatment protocols and complicated procedures are important factors limiting the use of regional citrate anticoagulation (RCA) technology in hemodialysis. This study aims to validate the safety and efficacy of a simplified individualized RCA protocol for hemodialysis.

MATERIALS AND METHODS

From June 2019 to August 2019, 45 patients with active bleeding or bleeding tendency undergoing maintenance hemodialysis in the Nephrology Department of the First Affiliated Hospital of Nanchang University were randomly divided into a modified conventional RCA protocol group with a low-flux dialyzer, a simplified individualized RCA protocol group with a high-flux dialyzer, and a simplified individualized RCA protocol group with a low-flux dialyzer.

RESULTS

A total of 45 patients were included in this study. The mean age of the patients was 57.38 ± 19.05 years, and 78% were men. Forty-three patients completed 4 hours of hemodialysis, and the median total clotting scores in the 3 groups were 11, 12, and 12. Compared with the modified conventional RCA protocol group with a low-flux dialyzer, the 2 simplified individualized RCA protocol groups had better clotting scores for the dialyzer, arterial bubble trap, and single-pool urea clearance index (spKt/VBUN) and lower costs. Moreover, these parameters did not differ between the 2 simplified individualized RCA protocol groups. No electrolyte or acid-base imbalances or citrate poisoning was observed in any of the 3 groups. Adverse events did not differ significantly among the 3 groups.

CONCLUSIONS

The simplified individualized RCA protocol is safe, effective, and easy to implement. Therefore, this protocol can be promoted for clinical practice.

TRIAL REGISTRATION

This study was registered in the Chinese Clinical Study Registry under registration number ChiCTR1900023801.

A target-oriented algorithm for maintaining serum calcium stability automatically in regional citrate anticoagulation

BACKGROUND

Regional citrate anticoagulation (RCA) for renal replacement therapy is widely practiced in critically ill patients. However, concern exists regarding its labor-intensiveness for monitoring and the associated hypocalcemia. In this study, we provided an algorithm for prescribing RCA and evaluated its safety in patients.

METHODS

During 18 hemofiltration treatments with calcium-free replacement solution, participants were randomized to receive algorithm-based or trial-and-error RCA protocol. The effluent volume, post-filter and in vivo ionized calcium (iCa), and calcium in the sera and effluents were periodically measured at an interval of 1 to 2 h.

RESULTS

For patients received algorithm-based RCA protocol, no one had a serum iCa less than 0.9 mmol/L, and none needed calcium supplement adjustment to maintain serum calcium stability. For patients accepted trial-and-error protocol, all patients had a serum iCa below 0.9 mmol/L, their serum iCa and calcium levels fluctuated dramatically, and all patients need additional calcium supplement adjustment during RCA. None of the participants showed a post-filter iCa > 0.4 mmol/L.

CONCLUSION

We provided a safe algorithm for calculating calcium supplementation doses that could maintain serum calcium stability without additional adjustment during RCA.

Continuous Renal Replacement Therapy in Venovenous Extracorporeal Membrane Oxygenation: A Retrospective Study on Regional Citrate Anticoagulation

Systemic infusion of unfractionated heparin (UFH) is the standard anticoagulation technique for continuous renal replacement therapy (CRRT) during extracorporeal membrane oxygenation (ECMO), but often fails to avoid CRRT circuit clotting. The aim of this study was to assess, in patients undergoing CRRT during venovenous ECMO (vv-ECMO), the efficacy and safety of adding regional citrate anticoagulation (RCA) for CRRT circuit anticoagulation (RCA + UFH group) compared with the sole systemic heparin anticoagulation (UFH group). We performed a retrospective chart review (2009-2018) of patients treated with CRRT during ECMO. We evaluated filter life span, rate of CRRT circuit clotting, and coagulation parameters. The incidence of citrate anticoagulation-related complications was recorded. Forty-eight consecutive adult patients underwent CRRT during vv-ECMO in the study period. The incidence of CRRT circuit clotting was lower in the RCA + UFH group (11% vs. 38% in the UFH group, p < 0.001). Log-rank survival analysis demonstrated longer circuit lifetime for RCA + UFH group. No complication ascribable to citrate anticoagulation was recorded. Regional citrate anticoagulation resulted a feasible, safe, and effective technique as additional anticoagulation for CRRT circuits during ECMO. Compared with systemic heparinization only, this technique allowed to reduce the rate of CRRT circuit clotting.

Metformin-Induced Lactic Acidosis: A Question of Time

Metformin is an oral antidiabetic largely prescribed in the treatment of type II diabetes. Overdose is associated with life-threatening lactic acidosis. We report the case of the highest metformin concentration ever described secondary to a voluntary suicidal intake. The patient developed a severe lactic acidosis and hemodynamic shock successfully treated with high-flow hemofiltration. Time to start extrarenal epuration is capital to avoid poor evolution.

Sustained low-efficiency dialysis with regional citrate anticoagulation for patients with liver impairment in intensive care unit: A single-center experience

Regional citrate anticoagulation (RCA) is a recommended method for extracorporeal circuit anticoagulation during renal replacement therapy (RRT). Increased risk of citrate accumulation by default of hepatic metabolism limits its use in liver failure patients. A Ca_tot /Ca_ion ratio ≥2.5 is established as an indirect control of plasma citrate poisoning. To investigate the safety of RCA in patients with liver impairment during sustained low-efficiency dialysis (SLED), we conducted a retrospective study of 41 patients with acute or chronic hepatocellular failure requiring RRT between January 2014 and June 2015 in the intensive care unit of the Groupe Hospitalier Sud Ile de France. Sixty-seven SLED sessions were performed. At admission, 32 (78%) patients had acute liver dysfunction and nine (22%) patients had cirrhosis with a median MELD score of 27 (IQR: 18.8, 42.0). Despite a majority of poor prognosis patients (SAPS-II (Simplified Acute Physiology Score II) score 71 [IQR: 58; 87]), with acute liver impairment as a part of multi-organ failure, no dosage of Ca_tot /Ca_ion ratio after SLED sessions exceeded the critical threshold of 2.5. Of the 63 complete sessions, neither dyscalcemia nor major dysnatremia, nor extracorporeal circuit thrombosis were noticed. Observed acid-base disturbances (16.4%) were not significantly correlated with the Ca_tot /Ca_ion ratio (P = .2155). In this retrospective study using RCA during intermittent RRT in ICU patients with severe liver dysfunction, we did not observe any citrate accumulation but monitoring of acid-base status and electrolytes remains necessary to ensure technique safety.

A novel predictive score for citrate accumulation among patients receiving artificial liver support system therapy with regional citrate anticoagulation

Patients with liver failure may suffer citrate accumulation when using regional citrate anticoagulation for artificial liver support system therapy (RCA-ALSS therapy). This study aimed to develop a predictive scoring system to stratify the risk of citrate accumulation. A total of 338 patients treated with RCA-ALSS therapy were retrospectively enrolled and randomly divided into derivation and validation cohorts. Longer duration of citrate accumulation (LDCA) was defined as the presence of citrate accumulation 2 h after RCA-ALSS therapy. Four baseline variables were found to be independently associated with LDCA: gender, international normalized ratio of prothrombin time, serum creatinine, and serum chloride. A predictive R-CA model and its simplified R-CA score were developed. The R-CA model (AUROC = 0.848) was found to be superior to the MELD score (AUROC = 0.725; p = 0.022) and other univariate predictors (AUROCs < 0.700; all p ≤ 0.001) in predicting LDCA. The R-CA score (AUROC = 0.803) was as capable as the R-CA model (p = 0.369) and the MELD score (p = 0.174), and was superior to other univariate predictors (all p < 0.05) in predicting LDCA. An R-CA score of 0–2 had a negative predictive value of 90.2% for LDCA. Our R-CA score reliably predicts LDCA in patients with RCA-ALSS therapy, and it is easy to use. Patients with R-CA score of 0–2 can safely receive RCA-ALSS therapy, while others should be carefully evaluated before treatment.

Trial registration: Chinese Clinical Trial Registry, ChiCTR2000029179. Registered 17 January 2020, https://www.chictr.org.cn/showproj.aspx?proj=48084.

Detoxification of bilirubin and bile acids with intermittent coupled plasmafiltration and adsorption in liver failure (HERCOLE study)

Background

CPFA is an extracorporeal treatment used in severe sepsis to remove circulating proinflammatory cytokines. Limited evidence exists on the effectiveness of bilirubin adsorption by the hydrophobic styrenic resin, the distinctive part of CPFA. The aim of this study is to validate CPFA effectiveness in liver detoxification.

Methods

In this prospective observational study, we enrolled patients with acute or acute-on-chronic liver failure (serum total bilirubin > 20 mg/dL or MELD Score > 20) hospitalized from June 2013 to November 2017. CPFA was performed using the Lynda (Bellco/MedTronic, Mirandola, Italy) or the Amplya (Bellco/MedTronic, Mirandola, Italy) machines. Anticoagulation was provided with unfractionated heparin or citrate. Bilirubin and bile acids reduction ratios per session (RRs) were the main parameters for hepatic detoxification.

Results

Twelve patients with acute (n = 3) or acute-on-chronic (n = 9) liver failure were enrolled. Alcohol was the main cause of liver disease. Thirty-one CPFA treatments of 6 h each were performed, 19 with heparin and 12 with citrate. RRs was 28.8% (range 2.2–40.5) for total bilirubin, 32.7% (range 8.3–48.9) for direct bilirubin, 29.5% (range 6.5–65.4) for indirect bilirubin and 28.9% (16.7- 59.7) for bile acids. One patient received liver transplantation and 8/9 were alive at 1 year of follow-up. Three patients (25%) died: 2 during hospitalization and 1 for a cardiac event at 4 months of follow up with restored liver function.

Conclusions

CPFA resulted to be effective in liver detoxification. Thus, it may be considered as a “bridge technique” both to the liver transplant and to the recovery of the basal liver function.

Determinants of Total/ionized Calcium in patients undergoing citrate CVVH: A retrospective observational study

PURPOSE

To identify potential determinants of the Total/ionized Ca ratio (T/iCa), a marker of citrate accumulation.

MATERIALS AND METHODS

Single-center retrospective observational study evaluating citrate dose, citrate target, albumin, phosphate, pH, lactate, and APACHE II score as potential determinants. Linear mixed models (LMM) using citrate dose and citrate target were developed describing associations with T/iCa.

RESULTS

From a dataset of 471 samples in 103 patients, an LMM in 379 complete samples (95 patients) sets revealed that citrate dose, pH, phosphate, albumin and APACHE were interactively related to T/iCa. A rising citrate dose was associated with a higher increase in T/iCa when phosphate was high, and less when phosphate was low. A rising albumin was associated with a higher increase in T/iCa when APACHE was high and phosphate was low and less when APACHE was low and phosphate high. In case of acidosis, a rising lactate was associated with a higher increase in T/iCa. In the LMM using citrate target, citrate target and pH were the main independent predictors of T/iCa with albumin, phosphate and APACHE score as modifiers.

CONCLUSIONS

Besides citrate dose, a high pH and high phosphate, albumin and APACHE are also associated with a rising T/iCa.

Regional citrate anticoagulation versus no-anticoagulation for continuous venovenous hemofiltration in patients with liver failure and increased bleeding risk: A retrospective case-control study

Objective

There are controversial opinions on anticoagulation for continuous venovenous hemofiltration (CVVH) in patients with liver failure (LF) and increased bleeding risk. Therefore, we conducted a retrospective study to evaluate the efficacy and safety of regional citrate anticoagulation (RCA) versus no-anticoagulation for CVVH in these patients.

Methods

The included patients were divided into RCA and no-anticoagulation group according to the CVVH anticoagulation strategy they accepted for CVVH. Filter lifespan, bleeding, citrate accumulation, catheter occlusion, and totCa/ionCa ratio were evaluated as outcomes.

Results

In the original cohort, the filter lifespan of the RCA group (41 patients, 79 filters) was significantly longer than the no-anticoagulation group (62 patients, 162 filters) (> 72 hours vs 39.5 hours (IQR 31.2–47.8), P = 0.002). The adjusted results demonstrated that RCA could significantly reduce the risk of filter failure (HR = 0.459, 95%CI 0.26–0.82, P = 0.008). Four episodes of totCa/ionCa > 2.5 were observed in the RCA group and continuously accepted RCA-CVVH after the reduction of citrate dose and blood flow. No obvious citrate accumulation was observed in these patients. In the matched cohort, the filter lifespan of the RCA group was significantly longer than the no-anticoagulation group (P = 0.013) as well. No significant difference in the episodes of totCa/ionCa > 2.5 was observed between the two matched groups (P = 0.074). Both in the original cohort and the matched cohort, the bleeding, acidosis, alkalosis, and catheter occlusion incidences were not significantly different between the two groups.

Conclusions

In LF patients with increased bleeding risk who underwent CVVH, RCA could prolong the filter lifespan and be safely used with careful blood gas monitoring and citrate dose adjusting. Further prospective, randomized, control studies are warranted to obtain robust evidences.

Serial measurement of electrolyte and citrate concentrations in blood-primed continuous hemodialysis circuits during closed-circuit dialysis

BACKGROUND

For continuous renal replacement therapy in small infants, due to the large extracorporeal volume involved, blood priming can be necessary to prevent hypotension and hemodilution. Because packed red blood cells (RBCs) have high levels of potassium and citrate, closed-circuit dialysis is often performed. We assessed the metrics of closed-circuit dialysis and serial citrate concentration changes.

METHODS

We performed dialysis of closed circuits primed with expired human packed RBC solution and 5% albumin. Blood and dialysate flow rates were 70 and 33.3 mL/min, respectively. The extracorporeal volume was 70 mL. We measured pH, electrolytes, and citrate in the closed circuit every 3 min for 15 min. We also assessed the adequacy of closed-circuit dialysis using the formula: [dialysate flow rate (mL/min) × time of dialysis (min)]/extracorporeal volume (mL) and we assessed the correlation between citrate and ionized calcium concentrations.

RESULTS

To reach normal concentrations of sodium, potassium, and chloride, 2.4 times as much dialysate fluid as extracorporeal volume was needed. In contrast, for ionized calcium, bicarbonate, and citrate, 3.8 times as much dialysate fluid as extracorporeal volume was required. By simple linear regression analysis, the concentration of citrate was significantly correlated with that of ionized calcium.

CONCLUSIONS

For closed-circuit dialysis using an RBC solution, the formula [dialysate flow rate (mL/min) × time of dialysis (min)]/extracorporeal volume (mL) would be a better parameter to estimate efficacy, compared with other metrics. Additionally, the citrate concentration can be readily estimated from the ionized calcium concentration during closed-circuit dialysis.

Regional citrate anticoagulation with a substitute containing calcium for continuous hemofiltration in children

Regional citrate anticoagulation (RCA) was recommended as the first treatment option for adults by the Kidney Disease Improving Global Outcomes Kidney Foundation in 2012, for the characteristic of sufficient anticoagulation in vitro, but almost no anticoagulation in vivo. Traditionally, the substitute for RCA is calcium-free. This study investigated a simplified protocol of RCA for continuous hemofiltration (CHF) in children using a commercially available substitute containing calcium.An analytical, observational, retrospective study assessed 59 pediatric patients with 106 sessions and 3580 hours of CHF. Values before and after treatment were compared, including Na, ionic calcium (iCa) and HCO3 concentrations, pH, and the ratio of total calcium to iCa (T/iCa). In addition, in vivo and in vitro iCa, treatment time, sessions with continuous transmembrane pressure >200 mm Hg, and sessions with clotting and bleeding were recorded.The average treatment time was 33.8 ± 10.1 hours. In vitro, 88.5% of iCa achieved the target (0.25-0.35 mmol/L), and in vivo, 95.4% of iCa achieved the target (1.0-1.35 mmol/L). There were 8 sessions with a transmembrane pressure >200 mm Hg and 3 sessions with filters clotted. After treatment, there were 2, 1, and 2 sessions with T/iCa > 2.5 (implying citrate accumulation), iCa < 0.9 mmol/L, and iCa > 1.35 mmol/L. No sodium disorders were recorded. There were fewer cases of acidemia and more cases of alkalemia after treatment compared to before.RCA-CHF with a substitute containing calcium and close monitoring could be a safe and effective treatment for children. In addition, the calcium test site in vitro and the adjustment of citrate should be given strict attention.

Regional citrate anticoagulation for continuous renal replacement therapy

PURPOSE OF REVIEW

The delivery of an effective dialysis dose in continuous renal replacement therapy (CRRT) depends on adequate anticoagulation of the extracorporeal circuit. In most patients, either systemic heparin anticoagulation (SHA) or regional citrate anticoagulation (RCA) is used. This review will outline the basics and rationale of RCA and summarize data on safety and efficacy of both techniques.

RECENT FINDINGS

The basic principle of RCA is to reduce the level of ionized calcium in the extracorporeal circuit via infusion of citrate. This way, effective anticoagulation restricted to the extracorporeal circuit is achieved. SHA and RCA were compared in a variety of studies. RCA significantly prolonged filter lifetime, reduced bleeding complications and provided excellent control of uremia and acid-base status. RCA was also safe in the majority of patients with impaired liver function, whereas caution must be exerted in those with severe multiorgan failure and persistent hyperlactatemia.

SUMMARY

RCA per se is safe and effective for anticoagulation of CRRT. Compared to SHA, efficacy of anticoagulation is improved and adverse effects are reduced. RCA can be recommended as the anticoagulation mode of choice for CRRT in most ICU patients.

Membrane-based therapeutic plasma exchange in dogs: Prescription, anticoagulation, and metabolic response

BACKGROUND

Therapeutic plasma exchange (TPE) is used increasingly in small animals to remove circulating large molecular products such as antibodies, pathogenic proteins, and protein-bound toxins. Specific, efficient, and safe protocols need to be developed.

HYPOTHESIS/OBJECTIVES

To describe the technique of membrane-based TPE, the resulting physiological and metabolic changes, and to define an adequate regional citrate anticoagulation protocol.

ANIMALS

Thirty-four dogs treated with TPE (2011-2017).

METHODS

Retrospective review of all TPE treatments performed at the Vetsuisse Faculty, University of Bern, identified through a search of the institutional database for extracorporeal treatments.

RESULTS

Sixty-four treatments were performed, resulting in 1.0 plasma volume exchange (range, 0.4-1.1). Replacement fluids included fresh frozen plasma (12%-100% volume), colloids (0%-52%), human albumin (0%-41%), and saline (0%-70%). Anticoagulation was performed with regional citrate (n = 24), systemic heparinization (n = 2), or combined (n = 38). Main relevant laboratory changes included a 24.7% decrease in total proteins (interquartile range, 16.7-31.4; P < .001), 53% in fibrinogen (-30 to 63; P = .009), 36% in bilirubin (13-43, P = .02), 9.0% in urea (0.7-15.7; P < .001), and 4.5% in creatinine (-6.6 to 10.6; P = .006). Citrate accumulation was evidenced in all dogs, more pronounced in those with renal but not with hepatic impairment. Maximal tolerable citrate rates were estimated as 5.5 and 9.0 μmol/kg/min for treatments in dogs with and without renal impairment, respectively. Complications were observed in 22 treatments (34%) and were fatal in 2 dogs.

CONCLUSIONS AND CLINICAL IMPORTANCE

Therapeutic plasma exchange causes metabolic and biochemical alterations. Understanding these effects makes possible to anticipate most complications and to improve safety of the procedure.

Safety and efficacy of regional citrate anticoagulation for continuous renal replacement therapy in liver failure patients: a systematic review and meta-analysis

Background

Regional citrate anticoagulation (RCA) is a widely used strategy for continuous renal replacement therapy (CRRT). Most of the current guidelines recommend liver failure as one of the contraindications for citrate anticoagulation. However, some studies suggested that the use of citrate for CRRT in liver failure patients did not increase the risk of citrate-related complications. The purpose of this systematic review is to summarize the current evidences on the safety and efficacy of RCA for CRRT in liver failure patients.

Methods

We performed a comprehensive search on PubMed, Embase, and the Cochrane Library databases from the inception to March 1, 2018. Studies enrolled adult (age > 18 years) patients with various levels of liver dysfunction underwent RCA-CRRT were included in this systematic review.

Results

After the study screening, 10 observational studies with 1241 liver dysfunction patients were included in this systematic review. The pooled rate of citrate accumulation and bleeding was 12% [3%, 22%] and 5% [2%, 8%], respectively. Compared with the baseline data, the serum pH, bicarbonate, and base excess (BE), the rate of metabolic alkalosis, the serum ionized calcium (ionCa) and total calcium (totCa) level, and the ratio of total calcium/ionized calcium (totCa/ionCa) significantly increased at the end of observation. However, no significant increase was observed in serum citrate (MD − 65.82 [− 194.19, 62.55]), lactate (MD 0.49 [− 0.27, 1.26]) and total bilirubin concentration (MD 0.79 [− 0.70, 2.29]) at the end of CRRT. Compared with non-liver failure patients, the live failure patients showed no significant difference in the pH (MD − 0.04 [− 0.13, 0.05]), serum lactate level (MD 0.69 [− 0.26, 1.64]), and totCa/ionCa ratio (MD 0.03 [− 0.12, 0.18]) during CRRT. The median of mean filter lifespan was 55.9 h, with a range from 22.7 to 72 h.

Conclusions

Regional citrate anticoagulation seems to be a safe anticoagulation method in liver failure patients underwent CRRT and could yield a favorable filter lifespan. Closely monitoring the acid base status and electrolyte balance may be more necessary during RCA-CRRT in patients with liver failure.

Electronic supplementary material

The online version of this article (10.1186/s13054-019-2317-9) contains supplementary material, which is available to authorized users.