Dose of nafamostat mesylate during continuous kidney replacement therapy in critically ill patients: a two-centre observational study.

BACKGROUND: Nafamostat mesylate is an anticoagulant used for critically ill patients during continuous kidney replacement therapy (CKRT), characterised by its short half-life. However, its optimal dosage remains unclear. This study aimed to explore the optimal dosage of nafamostat mesylate during CKRT. METHODS: We conducted a two-centre observational study. We screened all critically ill adult patients who required CKRT in the intensive care unit (ICU) from September 2013 to August 2021; we included patients aged ≥ 18 years who received nafamostat mesylate during CKRT. The primary outcome was filter life, defined as the time from CKRT initiation to the end of the first filter use due to filter clotting. The secondary outcomes included safety and other clinical outcomes. The survival analysis of filter patency by the nafamostat mesylate dosage adjusted for bleeding risk and haemofiltration was performed using a Cox proportional hazards model. RESULTS: We included 269 patients. The mean dose of nafamostat mesylate was 15.8 mg/hr (Standard deviation (SD), 8.8; range, 5.0 to 30.0), and the median filter life was 18.3 h (Interquartile range (IQR), 9.28 to 36.7). The filter survival analysis showed no significant association between the filter life and nafamostat mesylate dosage (hazard ratio 1.12; 95 CI 0.74-1.69, p = 0.60) after adjustment for bleeding risk and addition of haemofiltration to haemodialysis. CONCLUSIONS: We observed no dose-response relationship between the dose of nafamostat mesylate (range: 5 to 30 mg/h) and the filter life during CKRT in critically ill patients. The optimal dose to prevent filter clotting safely needs further study in randomised controlled trials. TRIAL REGISTRATION: Not applicable.

Unfractionated heparin versus nafamostat mesylate for anticoagulation during continuous kidney replacement therapy: an observational study.

BACKGROUND: Unfractionated heparin sodium and nafamostat mesylate have long been used as anticoagulants in continuous kidney replacement therapy (CKRT) where citrate is unavailable. This study aimed to determine whether heparin or nafamostat mesylate used during CKRT was associated with a longer filter life. METHODS: In this single-centre observational study, we included adult patients who required CKRT and used heparin or nafamostat mesylate for their first CKRT in the intensive care unit from September 1, 2013, to December 31, 2020. The primary outcome was filter life (from the start to the end of using the first filter). We used propensity score matching to adjust for the imbalance in patients' characteristics and laboratory data at the start of CKRT and compared the outcomes between the two groups. We also performed restricted mean survival time analysis to compare the filter survival times. RESULTS: We included 286 patients, 157 patients on heparin and 129 patients on nafamostat mesylate. After propensity score matching, the mean filter life with heparin was 1.58 days (N = 91, Standard deviation [SD], 1.52) and with nafamostat mesylate was 1.06 days (N = 91, SD, 0.94, p = 0.006). Multivariable regression analysis adjusted for confounding factors supported that heparin was associated with a longer filter life compared with nafamostat mesylate (regression coefficient, days, 0.52 [95% CI, 0.15, 0.89]). The between group difference of the restricted mean filter survival time in the matched cohort was 0.29 (95% CI, 0.07-0.50, p = 0.008). CONCLUSION: Compared to nafamostat mesylate, heparin was associated with one-third to one-half a day longer filter life. TRIAL REGISTRATION: Not applicable.

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.

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

OBJECTIVE: Regional citrate anticoagulation (RCA) is the preferred anticoagulation method for continuous kidney replacement therapy (CKRT) recommended by KDIGO. Limited availability of calcium-free solutions often imposes challenges to the implementation of RCA for CKRT (RCA-CKRT). The principal purpose of this study was to characterize the outcomes of RCA-CKRT using calcium-containing solutions. STUDY DESIGN: Retrospective cohort study. SETTING & PARTICIPANTS: We evaluated the safety and efficacy of RCA-CKRT with calcium-containing dialysate and replacement fluid used for 128 patients. A total of 571 filters and 1,227 days of CKRT were analyzed. EXPOSURES: Liver disease, sepsis in the absence of liver disease, and sepsis with liver disease. OUTCOMES: Filter life and metabolic complications per 100 CKRT days. ANALYTICAL APPROACH: Linear mixed-effects model and generalized linear mixed-effects models. RESULTS: The majority of patients were male (91; 71.1%), 32 (25%) had liver disease, and 29 (22.7%) had sepsis without liver disease. Median filter life was 50.0 (interquartile range, 22.0-118.0) hours, with a maximum of 322 hours, and was significantly lower (33.5 [interquartile range, 17.5-60.5] h) in patients with liver disease. Calcium-containing replacement solutions were used in 41.6% of all CKRT hours and reduced intravenous calcium requirements by 31.7%. Hypocalcemia (ionized calcium<0.85mmol/L) and hypercalcemia (total calcium>10.6mg/dL) were observed in 6.0 and 6.7 per 100 CKRT days, respectively. Citrate accumulation was observed in 13.3% of all patients and was associated with metabolic acidosis in 3.9%, which was not significantly different in patients with liver disease (9.3%; P = 0.2). LIMITATIONS: Lack of control groups that used calcium-free dialysate and replacement solutions with RCA-CKRT. Possible overestimation of filter life from incomplete data on cause of filter failure. CONCLUSIONS: Our study suggests that RCA-CKRT with calcium-containing solutions is feasible and safe in critically ill patients, including those with sepsis and liver disease.

Continuous Renal Replacement Therapy Without Anticoagulation: Top Ten Tips to Prevent Clotting.

Continuous renal replacement therapy (CRRT) is intended to function continuously and is prescribed for this outcome. Anticoagulants may not always be used. Clotting and clogging within the CRRT filter stopping therapy occurs with a variability in the total elapsed time associated. This is commonly known as the circuit or filter "life". It is very useful and important to record this time at the bedside and refer to this as a measure of success and quality. Filter life (i.e., hours) is reported in many reports investigating CRRT but is not well understood or clear for when this is considered inadequate and clinical review strategies should be considered. Failure before 8 h could be associated with inadequate renal support and "therapy". Anticoagulation is the key intervention to prolong filter function; however, the extracorporeal circuit design and set up, access catheter profile and insertion site, CRRT machine settings, and the human interface operating CRRT are always important and the only consideration to prevent failure when no anticoagulation is mandated for CRRT.

Continuous hemofiltration model using porcine blood for comparing filter life.

The purpose of the present study was to establish a continuous hemofiltration model using porcine blood to compare filter life. Continuous hemofiltration (CHF) experiments were performed using an in vitro hemofilter evaluation system utilizing porcine blood containing trisodium citrate in addition to nafamostat mesilate as anticoagulants. The lifetime of the hemofilter was evaluated using the transmembrane pressure and the pressure drop across the hemofilter at varying trisodium citrate concentrations. The porcine blood used in this experiment was considered to be in a slightly hypercoagulable state because of the continuous contact with non-biological materials and calcium inflow from substitution fluid. Blood containing 7 or 8 mM of trisodium citrate and nafamostat mesilate could be effectively used to compare the lifetimes of hemofilters utilized under the same conditions. In this CHF model using porcine blood, the plugging of the hollow fibers occurred shortly after the plugging of the membrane pores. In conclusion, a CHF model using porcine blood can be established by adjusting the concentration of trisodium citrate added to the blood.

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

BACKGROUND: Optimising filter life and performance efficiency in continuous renal replacement therapy has been a focus of considerable recent research. Larger high quality studies have predominantly focussed on optimal anticoagulation however CRRT is complex and filter life is also affected by vascular access, circuit and management factors. We performed a systematic search of the literature to identify and quantify the effect of vascular access, circuit and patient factors that affect filter life and presented the results as a meta-analysis. METHODS: A systematic review and meta-analysis was performed by searching Pubmed (MEDLINE) and Ovid EMBASE libraries from inception to 29th February 2016 for all studies with a comparator or independent variable relating to CRRT circuits and reporting filter life. Included studies documented filter life in hours with a comparator other than anti-coagulation intervention. All studies comparing anticoagulation interventions were searched for regression or hazard models pertaining to other sources of variation in filter life. RESULTS: Eight hundred nineteen abstracts were identified of which 364 were selected for full text analysis. 24 presented data on patient modifiers of circuit life, 14 on vascular access modifiers and 34 on circuit related factors. Risk of bias was high and findings are hypothesis generating. Ranking of vascular access site by filter longevity favours: tunnelled semi-permanent catheters, femoral, internal jugular and subclavian last. There is inconsistency in the difference reported between femoral and jugular catheters. Amongst published literature, modality of CRRT consistently favoured continuous veno-venous haemodiafiltration (CVVHD-F) with an associated 44% lower failure rate compared to CVVH. There was a trend favouring higher blood flow rates. There is insufficient data to determine advantages of haemofilter membranes. Patient factors associated with a statistically significant worsening of filter life included mechanical ventilation, elevated SOFA or LOD score, elevations in ionized calcium, elevated platelet count, red cell transfusion, platelet factor 4 (PF-4) antibodies, and elevated fibrinogen. Majority of studies are observational or report circuit factors in sub-analysis. Risk of bias is high and findings require targeted investigations to confirm. CONCLUSION: The interaction of patient, pathology, anticoagulation, vascular access, circuit and staff factors contribute to CRRT filter life. There remains an ambiguity from published data as to which site and side should be the first choice for vascular access placement and what interaction this has with patient factors and timing. Early consideration of tunnelled semi-permanent access may provide optimal filter life if longer periods of CRRT are anticipated. There remains an absence of robust evidence outside of anti-coagulation strategies despite over 20 years of therapy delivery however trends favour CVVHD-F over CVVH.

Outside-In Hemofiltration for Prolonged Operation without Clogging.

Hemofiltration (HF) is used extensively for continuous renal replacement therapy, but long-term treatment is limited by thrombosis leading to fiber clogging. Maximum filter life is typically less than 20 hours. We have achieved for the first time continuous and consistent hemofiltration for more than 100 hours using outside-in hemofiltration with the blood flow into the inter-fiber space (IFS). Although thrombi do deposit in the IFS, they have minimal affect on the blood flow and filtrate flux due to the three-dimensional system of interconnected hydrodynamic flow channels in the IFS. Microscopic examination of sections of the fiber bundle showed that deposited thrombi have dimensions about the size of the gaps between the hollow fibers and remain isolated from each other. A simple mathematical model is developed to describe the effect of thrombus deposition on the fluid flow that accounts for the enhanced performance arising from the interconnected flow. The hydrodynamic advantage of outside-in HF decreases at low anticoagulant concentration due to the instability in the blood and the very high volume fraction of thrombi that deposit in the entrance zone of the filter. These results clearly demonstrate the significant potential advantages of using outside-in hemofiltration for long-term renal replacement therapy.

Impact of specialized renal technologists on optimizing delivery of continuous kidney replacement therapy in critical care areas a retrospective study.

BACKGROUND: Continuous renal replacement therapy (CKRT) is delivered to some of the most critically ill patients in hospitals. This therapy is expensive and requires coordination of multidisciplinary teams to ensure the prescribed dose is delivered. With increased demands on the critical care nursing staff and increased complexities of patients admitted to critical care units, we evaluated the role of specialized renal technologists in ensuring the prescribed dose is delivered. Therefore, the aim of this study is to investigate the impact of supporting intensive care unit nurses with specialized renal technologists on optimizing efficiency of CKRT sessions in the United Arab Emirates. METHODS: This is a retrospective study that compared critically ill patients on CKRT overseen by specialized renal technologists versus who are non-covered in the year 2021. RESULTS: A total of 331 sessions on 158 patients were included in the study. The mean filter life was longer in specialized renal technologists-covered patients compared to the non-covered group (66 vs. 59 h, p = 0.019). After adjustment by multiple regression analysis for risk factors (i.e., age, gender, mechanical ventilation, sepsis, mean arterial pressure, vasopressors, and SOFA) that may affect CKRT machines' filter life, presence of a specialized renal technologists resulted in significantly longer filter life (co-efficient 0.129; CI 95% 1.080, 11.970; p-value: 0.019). CONCLUSION: Our study suggests that specialized renal technologists play a vital role in prolonging CKRT machine's filter life span and optimizing CKRT machine's efficiency. Further research should focus on other potential benefits of having specialized renal technologists performing CKRT sessions, and to confirm the finding of this study. Additionally, a cost-benefit analysis could be conducted to determine the economic impact of having specialized teams performing CKRT.

Comparison of filter life span and solute removal during continuous renal replacement therapy: convection versus diffusion - A randomized controlled trial.

INTRODUCTION: This study aimed to investigate whether continuous veno-venous hemodiafiltration (CVVHDF) has a different filter life span and molecular solutes clearance when compared to continuous veno-venous hemofiltration (CVVH). METHODS: Sixty patients were enrolled in this study and randomly assigned to the CVVHDF (n = 30) or CVVH (n = 30) groups. Demographics, laboratory tests, urea, creatinine, IL-6, ß2-microglobulin, and myoglobulin clearance were recorded. RESULTS: Patients in the CVVH group had a shorter median time of filter life span compared with those in the CVVHDF group (20 vs. 37.5 h, p = 0.002). Urea and creatinine clearance were not significantly different between groups over time (p > 0.05). IL-6, ß2-microglobulin, and myoglobulin clearance were higher in the CVVH group. The transmembrane pressure (TMP) was significantly higher in the CVVH group. CONCLUSION: The use of CVVHDF may lead to a longer filter life span and lower clearance of medium and large molecules without affecting the small molecular solute clearance. TRIAL REGISTRATION: Chinese Clinical Trial Register (ChiCTR), ChiCTR2000029873. Registered 16 February 2020, http://www.chictr.org.cn/showproj.aspx?proj=49528.

Do anti-platelet drugs improve duration of continuous renal replacement therapy? A retrospective cohort study in cardiac ICU patients.

OBJECTIVE: The objective of this study was to investigate the impact of anti-platelet drug/s on duration of continuous renal replacement therapy (CRRT) in those patients where anti-coagulants were not used due to certain contraindications and in cases where patients were on anti-platelet drugs and were given anti-coagulant during CRRT. METHOD: This single-center, retrospective cohort study was conducted using the medical records patients treated with CRRT in the cardiac ICU of the inpatient urban facility, located in North India. Data was collected from only those patients who received CRRT for the duration of at least 12 h. Patient's in NAC group were not on any anti-platelet/s and did not receive anti-coagulant during CRRT. AC and AP group patients received anti-coagulant alone or were already on anti-platelet/s and did not receive anti-coagulant respectively while ACAP group patients were on anti-platelet drug/s and also received anti-coagulant during CRRT. RESULT: Patients in AC, AP, or ACAP group showed significantly (p < 0.001) higher CRRT filter life compared to NAC group. The median CRRT filter life was significantly higher in the ACAP group compared to AC (p < 0.05) and AP (p < 0.001) groups. CONCLUSION: This study indicates that systemic anti-platelet therapy can provide additional support in critical patients undergoing CRRT even with or without anti-coagulant therapy. However, the increase in CRRT filter life was more profound in patients who were on anti-platelet/s and also received anti-coagulant drug/s during CRRT.

Regional Citrate Anticoagulation Protocol for Patients with Presumed Absent Citrate Metabolism.

Background: Regional citrate anticoagulation (RCA) is not recommended in patients with shock or severe liver failure. We designed a protocol with personalized precalculated flow settings for patients with absent citrate metabolism that abrogates risk of citrate toxicity, and maintains neutral continuous KRT (CKRT) circuit calcium mass balance and normal systemic ionized calcium levels. Methods: A single-center prospective cohort study of patients in five adult intensive care units triaged to the CVVHDF-RCA "Shock" protocol. Results: Of 31 patients included in the study, 30 (97%) had AKI, 16 (52%) had acute liver failure, and five (16%) had cirrhosis at the start of CKRT. The median lactate was 5 mmol/L (interquartile range [IQR], 3.2-10.7), AST 822 U/L (IQR, 122-2950), ALT 352 U/L (IQR, 41-2238), total bilirubin 2.7 mg/dl (IQR, 1.0-5.1), and INR two (IQR, 1.5-2.6). The median first hemofilter life censored for causes other than clotting exceeded 70 hours. The cumulative incidence of hypernatremia (Na >148 mM), metabolic alkalosis (HCO3- >30 mM), and hypophosphatemia (P<2 mg/dl) were one out of 26 (4%), zero out of 30 (0%), and one out of 30 (3%), respectively, and were not clinically significant. Mild hypocalcemia occurred in the first 4 hours in two out of 31 patients, and corrected by hour 6 with no additional Ca supplementation beyond the per-protocol administered Ca infusion. The maximum systemic total Ca (tCa; mM)/ionized Ca (iCa; mM) ratio never exceeded 2.5. Conclusions: The Shock protocol can be used without contraindications and is effective in maintaining circuit patency with a high, fixed ACDA infusion rate to blood flow ratio. Keeping single-pass citrate extraction on the dialyzer >0.75 minimizes the risk of citrate toxicity even in patients with absent citrate metabolism. Precalculated, personalized dosing of the initial Ca-infusion rate from a table on the basis of the patient's albumin level and the filter effluent flow rate maintains neutral CKRT circuit calcium mass balance and a normal systemic iCa level.

Association between Intra-Circuit Activated Clotting Time and Incidence of Bleeding Complications during Continuous Renal Replacement Therapy using Nafamostat Mesilate: a Retrospective Pilot Observational Study.

It has been proposed that anticoagulant activity during continuous renal replacement therapy with nafamostat mesilate can be monitored by using intra-circuit activated clotting time. However, it is still unclear whether activated clotting time would be useful for this purpose. We conducted a retrospective study and included 76 patients who required continuous renal replacement therapy using nafamostat mesilate. We obtained information for pre- and post-filter activated clotting times and bleeding complications. We calculated time-weighted average activated clotting time. We divided the patients into three activated clotting time groups (low, middle, high) according to the tertiles of pre- and post-filter activated clotting times. Regarding post-filter time-weighted average activated clotting time, the incidence of bleeding complications in the high activated clotting time group was significantly higher than those in the low and middle activated clotting time groups (p=0.04). The incidences of bleeding complications were not significantly different among the three groups according to pre-filter time-weighted average activated clotting time (p=0.35). In sensitive analysis, the duration on continuous renal replacement therapy without bleeding complications was significantly longer for filters with post-tw ACT<262 than for those with post-tw ACT≥262 (p=0.03). This result suggested that post-filter time-weighted average activated clotting time might be a good predictor of bleeding complications during continuous renal replacement therapy with nafamostat mesilate. Further study is required to refute or confirm our findings.