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

Development and validation of a nomogram for circuit lifespan of regional citrate anticoagulation-continuous renal replacement therapy in intensive care patients with acute kidney injury

BACKGROUND

Regional citrate anticoagulation-continuous renal replacement therapy (RCA-CRRT) has a wide range of applications in clinical practice, but unplanned downtime due to RCA-CRRT circuit coagulation is as high as 15.75%-66.70%.

AIM

To build a nomogram model for predicting the lifespan circuits of RCA-CRRT.

STUDY DESIGN

A prospective observational cohort study was conducted in Sichuan, China. The collected clinical data from 404 RCA-CRRT sessions involving 135 patients were utilized. The patients' basic information, laboratory indicators and RCA-CRRT parameters were used as independent variables, and the survival status and survival time of RCA-CRRT circuits were used as dependent variables. A Cox multivariate analysis was performed to build the nomogram model for predicting the lifespan of RCA-CRRT circuits. The model was validated internally and externally.

RESULTS

The median lifespan of RCA-CRRT circuits was 28.0 (12.0-46.5) h, and the unplanned downtime rate was 23.76%. In the Cox multivariate analysis, venous pressure, haemoglobin, Sequential Organ Failure Assessment (SOFA), lactate, and blood transfusion were identified as statistically significant predictive factors for the lifespan of RCA-CRRT circuits (p < .05). Subsequently, a nomogram model for predicting the lifespan of RCA-CRRT circuits was developed. The AUC values for internal and external validation within the 12-72-h timeframe ranged from 0.648 to 0.816 and 0.613 to 0.956, respectively. Both the calibration curve and clinical decision curve demonstrated the model's good performance.

CONCLUSION

The nomogram model developed in this study demonstrates its efficacy in accurately predicting the lifespan circuits of RCA-CRRT.

RELEVANCE TO CLINICAL PRACTICE

Clinical nurses can use the prediction model to assess the lifespan of RCA-CRRT circuits, so as to formulate a personalized RCA-CRRT treatment plan for patients, thus reducing the unplanned downtime of RCA-CRRT.

Sterile water and regional citrate anticoagulation: A simple CRRT strategy for safe correction of severe hyponatraemia

BACKGROUND

Hyponatraemia is a prevalent electrolyte disturbance observed in critically ill patients. The rapid correction of low plasma sodium levels by continuous renal replacement therapy (CRRT) carries the risk of developing osmotic demyelination syndrome (ODS), which can be prevented by implementing an individualized CRRT method.

AIM

This study aims to introduce a CRRT protocol for the safe and gradual correction of severe hyponatraemia.

STUDY DESIGN

This retrospective case series study was conducted in an intensive care unit (ICU). All four patients with severe hyponatraemia (<125 mmol/L) and renal failure between October 1, 2022, and September 30, 2023, were treated by CRRT with sterile water and regional citrate anticoagulation (RCA). Data on patient demographics, laboratory biochemical parameters, urine outputs and CRRT-related adverse events were collected. Laboratory parameters and urine outputs were compared by paired t-tests before and after CRRT.

RESULTS

After CRRT, sodium levels were significantly increased (112.7 ± 6.7 vs. 141.9 ± 2.8 mmol/L, p = .005). Abnormal urine outputs, potassium, creatinine and bicarbonate were corrected (p for all <.05). Safe and gradual correction of hyponatraemia and internal environmental dysregulation was achieved in all patients without any complications related to CRRT, particularly ODS.

CONCLUSION

It is a novel and simple strategy to correct severe hyponatraemia effectively while ensuring the safety of patients that can be easily implemented by experienced nurse staff.

RELEVANCE TO CLINICAL PRACTICE

The sterile water-based protocol for postfilter dilution is safe to correct severe hyponatraemia with RCA and can be easily performed by experienced critical care nurses according to the precalculated formula. CRRT-trained, experienced ICU nurses are competent to initiate and adjust sterile water infusion discretely to prevent overcorrection of hyponatraemia.

Early experience of using regional citrate anticoagulation for continuous renal replacement therapy in critically ill patients in a resource-limited setting

AIM

Despite the superiority of regional citrate anticoagulation (RCA) in continuous renal replacement therapy (CRRT), its application is limited in resource-limited settings. We aim to explore the cost and safety of RCA for CRRT in critically ill patients, compared to usual care.

METHODS

This prospective observational study included patients requiring CRRT in a tertiary intensive care unit (ICU) from February 2022 to January 2023. They were classified to either the RCA or usual care groups based on the anticoagulation technique chosen by the treating physician, considering contraindications. The CRRT prescription follows the institutional protocol. All relevant data were obtained from the ICU CRRT-RCA charts and electronic medical records. A cost analysis was performed.

RESULTS

A total of 54 patients (27 per group) were included, with no demographic differences. Sequential Organ Failure Assessment score and lactate levels were significantly higher in the usual care group. The number of filters used were comparable (p = .108). The median filter duration in the RCA group was numerically longer (35.00 [15.50-56.00] vs. 23.00 [17.00-29.00] h), but not statistically significant (p = .253). The duration of mechanical ventilation, vasopressor requirement, and mortality were similar, but the RCA group had a significantly longer ICU stay. The rate of adverse events was similar, with four severe metabolic alkalosis cases in the RCA group. The RCA group had higher total cost per patient per day (USD 611 vs. 408; p = .013).

CONCLUSION

In this resource-limited setting, RCA for CRRT appeared safe and had clinically longer filter lifespan compared with usual care, albeit the increased cost.

A safe and effective protocol for postdilution hemofiltration with regional citrate anticoagulation

BACKGROUND

Regional citrate anticoagulation (RCA) is recommended during continuous renal replacement therapy. Compared to systemic anticoagulation, RCA provides a longer filter lifespan with the risk of metabolic alkalosis and impaired calcium homeostasis. Surprisingly, most RCA protocols are designed for continuous veno-venous hemodialysis or hemodiafiltration. Effective protocols for continuous veno-venous hemofiltration (CVVH) are rare, although CVVH is a standard treatment for high-molecular-weight clearance. Therefore, we evaluated a new RCA protocol for postdilution CVVH.

METHODS

This is a monocentric prospective interventional study to evaluate a new RCA protocol for postdilution CVVH. We recruited surgical patients with stage III acute kidney injury who needed renal replacement therapy. We recorded dialysis and RCA data and hemodynamic and laboratory parameters during treatment sessions of 72 h. The primary endpoint was filter patency at 72 h. The major safety parameters were metabolic alkalosis and severe hypocalcemia at any time.

RESULTS

We included 38 patients who underwent 66 treatment sessions. The mean filter lifespan was 66 ± 12 h, and 44 of 66 (66%) filters were patent at 72 h. After censoring for non-CVVH-related cessation of treatment, 83% of all filters were patent at 72 h. The delivered dialysis dose was 28 ± 5 ml/kgBW/h. The serum levels of creatinine, urea and beta2-microglobulin decreased significantly from day 0 to day 3. Metabolic alkalosis occurred in one patient. An iCa++ below 1.0 mmol/L occurred in four patients. Citrate accumulation did not occur.

CONCLUSIONS

We describe a safe, effective, and easy-to-use RCA protocol for postdilution CVVH. This protocol provides a long and sustained filter lifespan without serious adverse effects. The risk of metabolic alkalosis and hypocalcemia is low. Using this protocol, a recommended dialysis dose can be safely administered with effective clearance of low- and middle-molecular-weight molecules.

TRIAL REGISTRATION

The study was approved by the medical ethics committee of Heinrich-Heine University Duesseldorf (No. 2018-82KFogU). The trial was registered in the local study register of the university (No: 2018044660) on 07/04/2018 and was retrospectively registered at ClinicalTrials.gov (ClinicalTrials.gov Identifier: NCT03969966) on 31/05/2019.

The role of nafamostat mesylate anticoagulation in continuous kidney replacement therapy for critically ill patients with bleeding tendencies: a retrospective study on patient outcomes and safety

BACKGROUND

Continuous kidney replacement therapy (CKRT) is crucial in the management of acute kidney injury in intensive care units (ICUs). Nonetheless, the optimal anticoagulation strategy for patients with bleeding tendencies remains debated. This study aimed to evaluate patient outcomes and safety of nafamostat mesylate (NM) compared with no anticoagulation (NA) in critically ill patients with bleeding tendencies who were undergoing CKRT.

METHODS

This retrospective study enrolled 2,313 patients who underwent CKRT between March 2013 and December 2022 at the third affiliated hospital in South Korea. After applying the exclusion criteria, 490 patients were included in the final analysis, with 245 patients in the NM and NA groups each, following 1:1 propensity score matching. Subsequently, in-hospital mortality, incidence of bleeding complications, agranulocytosis, hyperkalemia, and length of hospital stay were assessed.

RESULTS

No significant differences were observed between the groups regarding the lengths of hospital and ICU stays or the incidence of agranulocytosis and hyperkalemia. The NM group showed a smaller decrease in hemoglobin levels during CKRT (-1.90 g/dL vs. -2.39 g/dL) and less need for blood product transfusions than the NA group. Furthermore, the NM group exhibited a survival benefit in patients who required transfusion of all three blood products.

CONCLUSION

NM is an effective and safe anticoagulant for CKRT in critically ill patients, especially those requiring transfusion of all three blood products. Although these findings are promising, further multicenter studies are needed to validate them and explore the mechanisms underlying the observed benefits.

Acetyl-CoA-dependent ac4C acetylation promotes the osteogenic differentiation of LPS-stimulated BMSCs

The impaired osteogenic capability of bone marrow mesenchymal stem cells (BMSCs) caused by persistent inflammation is the main pathogenesis of inflammatory bone diseases. Recent studies show that metabolism is disturbed in osteogenically differentiated BMSCs in response to Lipopolysaccharide (LPS) treatment, while the mechanism involved remains incompletely revealed. Herein, we demonstrated that BMSCs adapted their metabolism to regulate acetyl-coenzyme A (acetyl-CoA) availability and RNA acetylation level, ultimately affecting osteogenic differentiation. The mitochondrial dysfunction and impaired osteogenic potential upon inflammatory conditions accompanied by the reduced acetyl-CoA content, which in turn suppressed N4-acetylation (ac4C) level. Supplying acetyl-CoA by sodium citrate (SC) addition rescued ac4C level and promoted the osteogenic capacity of LPS-treated cells through the ATP citrate lyase (ACLY) pathway. N-acetyltransferase 10 (NAT10) inhibitor remodelin reduced ac4C level and consequently impeded osteogenic capacity. Meanwhile, the osteo-promotive effect of acetyl-CoA-dependent ac4C might be attributed to fatty acid oxidation (FAO), as evidenced by activating FAO by L-carnitine supplementation counteracted remodelin-induced inhibition of osteogenesis. Further in vivo experiments confirmed the promotive role of acetyl-CoA in the endogenous bone regeneration in rat inflammatory mandibular defects. Our study uncovered a metabolic-epigenetic axis comprising acetyl-CoA and ac4C modification in the process of inflammatory osteogenesis of BMSCs and suggested a new target for bone tissue repair in the context of inflammatory bone diseases.

Safety and Feasibility of Regional Citrate Anticoagulation for Continuous Renal Replacement Therapy With Calcium-Containing Solutions: A Randomized Controlled Trial

BACKGROUND

Calcium-free (Ca-free) solutions are theoretically the most ideal for regional citrate anticoagulation (RCA) in continuous renal replacement therapy (CRRT). However, the majority of medical centers in China had to make a compromise of using commercially available calcium-containing (Ca-containing) solutions instead of Ca-free ones due to their scarcity. This study was designed to probe into the potential of Ca-containing solution as a secure and efficient substitution for Ca-free solutions.

METHODS

In this prospective, randomized single-center trial, 99 patients scheduled for CRRT were randomly assigned in a 1:1:1 ratio to one of three treatment groups: continuous veno-venous hemodialysis Ca-free dialysate (CVVHD Ca-free) group, continuous veno-venous hemodiafiltration calcium-free dialysate (CVVHDF Ca-free) group, and continuous veno-venous hemodiafiltration Ca-containing dialysate (CVVHDF Ca-containing) group at cardiac intensive care unit (CICU). The primary endpoint was the incidence of metabolic complications. The secondary endpoints included premature termination of treatment, thrombus of filter, and bubble trap after the process.

RESULTS

The incidence of citrate accumulation (18.2% vs. 12.1% vs. 21.2%) and metabolic alkalosis (12.1% vs. 0% vs. 9.1%) did not significantly differ among three groups (p > 0.05 for both). The incidence of premature termination was comparable among the groups (18.2% vs. 9.1% vs. 9.1%, p = 0.582). The thrombus level of the filter and bubble trap was similar in the three groups (p > 0.05 for all).

CONCLUSIONS

In RCA-CRRT for CICU population, RCA-CVVHDF with Ca-containing solutions and traditional RCA with Ca-free solutions had a comparable safety and feasibility.

TRIAL REGISTRATION

ChiCTR2100048238 in the Chinese Clinical Trial Registry.

Let's stop talking about 'citrate toxicity'

PURPOSE OF REVIEW

Continuous renal replacement therapy (CRRT) is a vital medical intervention used in critically ill patients with acute kidney injury (AKI). One of the key components of adequate clearance with CRRT is the use of anticoagulants to prevent clotting of the extracorporeal circuit. Regional citrate anticoagulation is the most often recommended modality. The term 'citrate toxicity' is used to describe potential adverse effects of accumulation of citrate and subsequent hypocalcemia. However, citrate is itself not inherently toxic. The term and diagnosis of citrate toxicity are questioned in this review.

RECENT FINDINGS

Citrate is being increasingly used for regional anticoagulation of the CRRT circuit. Citrate accumulation is infrequent and can cause hypocalcemia and metabolic alkalosis, which are potential adverse effects. Citrate itself, however, is not a toxic molecule. The term 'citrate toxicity' has been used to denote hypocalcemia and metabolic acidosis. However, citrate administration is well known to cause systemic and urinary alkalinization and under certain circumstances, metabolic alkalosis, but is not associated itself with any 'toxic' effects.We review the existing literature and debunk the perceived toxicity of citrate. We delve into the metabolism and clearance of citrate and question current data suggesting metabolic acidosis occurs as the result of citrate accumulation.

SUMMARY

In conclusion, this article calls into question prevailing concerns about 'citrate toxicity'. We emphasize the need for a more nuanced understanding of its safety profile. We recommend discarding the term 'citrate toxicity' in favor of another frequently used, but more meaningful term: 'citrate accumulation'.

Heparin anticoagulation versus regional citrate anticoagulation for membrane therapeutic plasma exchange in patients with increased bleeding risk

Background Heparin anticoagulation (HA) is commonly employed for membrane therapeutic plasma exchange (mTPE). However, for patients with increased bleeding risk, there were controversial opinions on the use of HA versus regional citrate anticoagulation (RCA) for mTPE. Our present study aimed to evaluate the efficacy and safety of HA vs. RCA for mTPE in patients with increased bleeding risk.Methods Patients with increased bleeding risk who underwent mTPE between 2014 and 2021 in our center were screened. Observations of anticoagulation efficacy and safety were used as the study endpoints.Results A total of 108 patients with 368 mTPE sessions were included. Of the included patients, 38 and 70 received HA and RCA mTPE, respectively. There was no significant difference in the clotting of extracorporeal circuits between the HA and RCA groups (4.1% vs. 4.4%, p = 0.605). More bleeding episodes were observed in the HA group compared to the RCA group (16.4% vs. 4.4% mTPE sessions, p < 0.001). The frequency of postoperative transfusion within 24 h (11% vs. 3.4%, p = 0.007) was significantly different in the HA and RCA group. Anticoagulation strategy (HA vs. RCA; OR 5.659, 95%CI 2.266-14.129; p < 0.001), and mean arterial pressure (prior treatment, OR 1.052, 95%CI 1.019-1.086; p = 0.002) were independent risk factors of bleeding episodes. At the end of mTPE treatment, the incidence of metabolic alkalosis (16.7% vs. 54.1%, p = 0.027) and hypocalcemia (41.7% vs. 89.2%, p = 0.001) was significantly different in the HA (n = 5, 12 sessions) and RCA (n = 22, 74 sessions) groups, respectively.Conclusion RCA is as effective as HA for mTPE. However, for patients with increased bleeding risk, RCA is associated with a lower risk of bleeding, compared with HA. With careful monitoring and timely adjustment, RCA most likely is a safe and effective anticoagulation option for mTPE in patients with increased bleeding risk.

Rapid implementation of an emergency on-site CKRT dialysate production system during the COVID-19 pandemic

BACKGROUND

On December 29, 2021, during the delta wave of the Coronavirus Disease 2019 (COVID-19) pandemic, the stock of premanufactured solutions used for continuous kidney replacement therapy (CKRT) at the University of New Mexico Hospital (UNMH) was nearly exhausted with no resupply anticipated due to supply chain disruptions. Within hours, a backup plan, devised and tested 18 months prior, to locally produce CKRT dialysate was implemented. This report describes the emergency implementation and outcomes of this on-site CKRT dialysate production system.

METHODS

This is a single-center retrospective case series and narrative report describing and reporting the outcomes of the implementation of an on-site CKRT dialysate production system. All adults treated with locally produced CKRT dialysate in December 2021 and January 2022 at UNMH were included. CKRT dialysate was produced locally using intermittent hemodialysis machines, hemodialysis concentrate, sterile parenteral nutrition bags, and connectors made of 3-D printed biocompatible rigid material. Outcomes analyzed included dialysate testing for composition and microbiologic contamination, CKRT prescription components, patient mortality, sequential organ failure assessment (SOFA) scores, and catheter-associated bloodstream infections (CLABSIs).

RESULTS

Over 13 days, 22 patients were treated with 3,645 L of locally produced dialysate with a mean dose of 20.0 mL/kg/h. Fluid sample testing at 48 h revealed appropriate electrolyte composition and endotoxin levels and bacterial colony counts at or below the lower limit of detection. No CLABSIs occurred within 7 days of exposure to locally produced dialysate. In-hospital mortality was 81.8% and 28-day mortality was 68.2%, though illness severity was high, with a mean SOFA score of 14.5.

CONCLUSIONS

Though producing CKRT fluid with IHD machines is not novel, this report represents the first description of the rapid and successful implementation of a backup plan for local CKRT dialysate production at a large academic medical center in the U.S. during the COVID-19 pandemic. Though conclusions are limited by the retrospective design and limited sample size of our analysis, our experience could serve as a guide for other centers navigating similar severe supply constraints in the future.

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.

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.

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.

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.

Management for Electrolytes Disturbances during Continuous Renal Replacement Therapy

Despite the lack of proven superiority in mortality compared to intermittent hemodialysis, continuous renal replacement therapy (CRRT) is the preferred renal replacement therapy modality for critically ill patients with acute kidney injury (AKI) due to better hemodynamic stability and steady correction of electrolytes disturbances and volume overload. Multiple and complex electrolyte disorders in patients with AKI can be managed effectively with CRRT because controlled and predictable correction is feasible. Thus, CRRT has an advantage with safety over conventional hemodialysis, especially in patients with both renal dysfunction and electrolyte disorder that require a sophisticated treatment with avoidance of rapid correction. On the contrary, CRRT can potentially lead to paradoxical disturbance of electrolytes such as hypokalemia or hypophosphatemia, especially in patients under high dose or prolonged duration of CRRT treatment. These electrolytes related complications can be prevented with close monitoring followed by the appropriate use of CRRT fluids. Although there is a lack of solid evidence and standardized guideline for CRRT prescriptions, optimal management of various electrolyte disturbances can be achieved with individualized and tailored dialysate and replacement fluid prescriptions. Several commercially available CRRT solutions with varying compositions provide flexibility to manage electrolyte disorders and maintain the stability of electrolyte. In this review, we discuss various prescription methods to manage common electrolyte imbalances as well as preventative strategies to maintain electrolyte homeostasis during CRRT providing detailed protocols used in our center. This review may contribute to future research that can lead to the development of clinical practice guidelines.

Calcium-containing versus calcium-free replacement solution in regional citrate anticoagulation for continuous renal replacement therapy: a randomized controlled trial

BACKGROUND

A simplified protocol for regional citrate anticoagulation (RCA) using a commercial calcium-containing replacement solution, without continuous calcium infusion, is more efficient for use in continuous renal replacement therapy (CRRT). We aim to design a randomized clinical trial to compare the safety and efficacy between calcium-free and calcium-containing replacement solutions in CRRT with RCA.

METHODS

Of the 64 patients receiving RCA-based postdilution continuous venovenous hemodiafiltration (CVVHDF) enrolled from 2017 to 2019 in West China Hospital of Sichuan University, 35 patients were randomized to the calcium-containing group and 29 to the calcium-free replacement solution group. The primary endpoint was circuit lifespan and Kaplan-Meier survival analysis was performed. Secondary endpoints included hospital mortality, kidney function recovery rate, and complications. The amount of 4% trisodium citrate solution infusion was recorded. Serum and effluent total (tCa) and ionized (iCa) calcium concentrations were measured during CVVHDF.

RESULTS

A total of 149 circuits (82 in the calcium-containing group and 67 in the calcium-free group) and 7609 circuit hours (4335 h vs. 3274 h) were included. The mean circuit lifespan was 58.1 h (95% CI 53.8-62.4 h) in the calcium-containing group vs. 55.3 h (95% CI 49.7-60.9 h, log rank P = 0.89) in the calcium-free group. The serum tCa and iCa concentrations were slightly lower in the calcium-containing group during CRRT, whereas the postfilter iCa concentration was lower in the calcium-free group. Moreover, the mean amounts of 4% trisodium citrate solution infusion were not significantly different between the groups (171.1 ± 15.9 mL/h vs. 169.0 ± 15.1 mL/h, P = 0.49). The mortality (14/35 [40%] vs. 13/29 [45%], P = 0.70) and kidney function recovery rates of AKI patients (19/26, 73% vs. 14/24, 58%, P = 0.27) were comparable between the calcium-containing and calcium-free group during hospitalization, respectively. Six (three in each group) patients showed signs of citrate accumulation in this study.

CONCLUSIONS

When compared with calcium-free replacement solution, RCA-based CVVHDF with calcium-containing replacement solution had a similar circuit lifespan, hospital mortality and kidney outcome. Since the calcium-containing solution obviates the need for a separate venous catheter and a large dose of intravenous calcium solution preparation for continuous calcium supplementation, it is more convenient to be applied in RCA-CRRT practice.

REGISTRATION

Chinese Clinical Trial Registry (www.chictr.org.cn, ChiCTR-IPR-17012629).

Impact of protocolized fluid management on electrolyte stability in patients undergoing continuous renal replacement therapy

Objective

Continuous renal replacement therapy (CRRT) is the standard treatment for critically ill patients with acute kidney injury (AKI). Electrolyte disturbance such as hypokalemia or hypophosphatemia occurs paradoxically in patients undergoing CRRT due to high clearance. We developed a fluid management protocol for dialysate and replacement fluid that depends on serum electrolytes and focuses on potassium and phosphate levels to prevent electrolyte disturbance during CRRT. The impact of our new fluid protocol on electrolyte stability was evaluated.

Methods

Adult patients who received CRRT between 2013 and 2017 were included. Patients treated 2 years before (2013–2014; pre-protocol group) and 2 years following development of the fluid protocol (2016–2017; protocol group) were compared. The primary outcomes were individual coefficient of variation (CV) and abnormal event rates of serum phosphate and potassium. Secondary outcomes were frequency of electrolyte replacement and incidence of cardiac arrhythmias. Individual CV and abnormal event rates for each electrolyte were analyzed using the Wilcoxon rank-sum test and Chi-square test with Yates’ continuity correction.

Results

A total of 1,448 patients was included. Both serum phosphate and potassium were higher in the protocol group. The CVs of serum phosphate (pre-protocol vs. protocol, 0.275 [0.207–0.358] vs. 0.229 [0.169–0.304], p &lt; 0.01) and potassium (0.104 [0.081–0.135] vs. 0.085 [0.064–0.110], p &lt; 0.01) were significantly lower in the protocol group. The abnormal event rates of serum phosphate (rate [95% CI], 0.410 [0.400–0.415] vs. 0.280 [0.273–0.286], p &lt; 0.01) and potassium (0.205 [0.199–0.211] vs. 0.083 [0.079–0.087], p &lt; 0.01) were also significantly lower in the protocol group.

Conclusion

The protocolized management of fluid in CRRT effectively prevented hypophosphatemia and hypokalemia by inducing excellent stability of serum phosphate and potassium levels.

The conundrum of the complex relationship between acute kidney injury and cardiac arrhythmias

Acute kidney injury (AKI) is defined by a rapid increase in serum creatinine levels, reduced urine output, or both. Death may occur in 16%-49% of patients admitted to an intensive care unit with severe AKI. Complex arrhythmias are a potentially serious complication in AKI patients with pre-existing or AKI-induced heart damage and myocardial dysfunction, fluid overload, and especially electrolyte and acid-base disorders representing the pathogenetic mechanisms of arrhythmogenesis. Cardiac arrhythmias, in turn, increase the risk of poor renal outcomes, including AKI. Arrhythmic risk in AKI patients receiving kidney replacement treatment may be reduced by modifying dialysis/replacement fluid composition. The most common arrhythmia observed in AKI patients is atrial fibrillation. Severe hyperkalemia, sometimes combined with hypocalcemia, causes severe bradyarrhythmias in this clinical setting. Although the likelihood of life-threatening ventricular arrhythmias is reportedly low, the combination of cardiac ischemia and specific electrolyte or acid-base abnormalities may increase this risk, particularly in AKI patients who require kidney replacement treatment. The purpose of this review is to summarize the available epidemiological, pathophysiological, and prognostic evidence aiming to clarify the complex relationships between AKI and cardiac arrhythmias.

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.

Treatment Effect of Regional Sodium Citrate Anticoagulation in Elderly Patients With High-Risk Bleeding Receiving Continuous Renal Replacement Therapy

Objective

To investigate the safety and efficacy of regional citrate anticoagulation (RCA) on elderly patients at high risk of bleeding after continuous renal replacement therapy (CRRT).

Methods

A total of 31 patients at high risk of bleeding who received CRRT in the intensive care unit were collected. The patients were divided into RCA group (n = 17) and no anticoagulation group (NA, n = 14) according to whether RCA was used or not. The levels of creatinine (Cr), blood urea nitrogen (BUN), prothrombin time (PT), activated partial thromboplastin time (APTT), total calcium (tCa), ionized calcium ion (iCa²⁺), sodium ion (Na⁺), bicarbonate ion (HCO₃⁻), tCa/iCa²⁺ ratio, and pH were observed after treatment. The filter use time, number of filters used, filter obstruction events, clinical outcomes, and safety evaluation indexes were compared post-treatment.

Results

After treatment, serum Cr and BUN levels, APTT and PT levels in the RCA group were significantly lower than the NA group. The tCa, iCa²⁺, HCO₃⁻, tCa/iCa²⁺, and pH were within the normal range after RCA treatment while Na⁺ levels saw a significant increase. In the RCA group, the filter using time was significantly longer, with significantly reduced numbers of filter use within 72 h and filter disorder events. Additionally, patients in the RCA group showed significant recovery of renal function and a significant reduction in bleeding events and in-hospital mortality.

Conclusion

RCA treatment significantly improves clinical outcome of patients at high risk of bleeding after CRRT, safely and effectively prolongs the filter life and avoids coagulation incidences.