Clinical study of blood purification therapy in critical care in Japan: results from the survey research of the Japan Society for Blood Purification in Critical Care in 2013

Clinical analysis of AN69ST membrane continuous venous hemofiltration in the treatment of severe sepsis

We aimed to investigate the clinical efficacy of blood purification technology based on cytokine adsorption in the treatment of sepsis. Sixty patients with sepsis were randomly divided into control (n = 30) and experimental (n = 30) groups. Both groups were given routine treatment and continuous venovenous hemofiltration, and on this basis, the experimental group received acrylonitrile/sodium methacrylate (AN69ST) blood purification. The levels of C-reactive protein, procalcitonin, white blood cell count, albumin, platelets, total bilirubin, creatinine, lactic acid, and APACE II score, as well as secretion of inflammatory factors interleukin (IL)-6 and tumor necrosis factor (TNF-α) were compared. The hospitalization time, mechanical ventilation (MV) time, drug use time, and mortality were analyzed. After treatment, the secretion levels of IL-6 and TNF-α were decreased, and other indicators were significantly improved compared with those before treatment (P < 0.05), especially in the experimental group (P < 0.05). The hospitalization time, MV time, and drug use time in the experimental group were significantly lower than those of the control group (P < 0.05), and the mortality was lower than that in the control group (P < 0.05). In conclusion, blood purification technology based on cytokine adsorption can significantly improve various indicators of sepsis patients, reduce hospitalization time, reduce mortality, and improve the prognosis.

How should we treat acute kidney injury caused by renal congestion?

Decreased kidney function is associated with increased risk of cardiovascular events and mortality, and heart failure (HF) is a wellknown risk factor for renal dysfunction. Acute kidney injury (AKI) in patients with HF often is attributed to prerenal factors, such as renal hypoperfusion and ischemia as a result of decreased cardiac output. Another such factor is reduction of absolute or relative circulating blood volume, with the decrease in renal blood flow leading to renal hypoxia followed by a decrease in the glomerular filtration rate. However, renal congestion is increasingly being recognized as a potential cause of AKI in patients with HF. Increased central venous pressure and renal venous pressure lead to increased renal interstitial hydrostatic pressure and a reduction of the glomerular filtration rate. Both decreased kidney function and renal congestion have been shown to be important prognostic factors of HF, and adequate control of congestion is important for improving kidney function. Loop and thiazide diuretics are recommended as standard therapies to reduce volume overload. However, these agents are associated with worsening renal function even though they are effective for improving congestive symptoms. There is growing interest in tolvaptan, which can improve renal congestion by increasing excretion of free water and decreasing the required dose of loop diuretic, thereby improving kidney function. This review summarizes renal hemodynamics, the pathogenesis of AKI due to renal ischemia and renal congestion, and diagnosis and treatment options for renal congestion.

Efficacy and safety of nafamostat mesilate anticoagulation in blood purification treatment of critically ill patients: a systematic review and meta-analysis

BACKGROUND

Nafamostat mesilate (NM), a broad-spectrum and potent serine protease inhibitor, can be used as an anticoagulant during extracorporeal circulation, as well as a promising drug effective against coronavirus disease 2019 (COVID-19). We conducted a systematic meta-analysis to evaluate the safety and efficacy of NM administration in critically ill patients who underwent blood purification therapy (BPT).

METHODS

The Cochrane Library, Web of Science and PubMed were comprehensively searched from inception to August 20, 2021, for potential studies.

RESULTS

Four randomized controlled trials (RCTs) and seven observational studies with 2723 patients met the inclusion criteria. The meta-analysis demonstrated that conventional therapy (CT) significantly increased hospital mortality compared with NM administration (RR = 1.25, p = 0.0007). In subgroup analyses, the in-hospital mortality of the NM group was significantly lower than that of the anticoagulant-free (NA) group (RR = 1.31, p = 0.002). The CT interventions markedly elevated the risk ratio of bleeding complications by 45% (RR = 1.45, p = 0.010) compared with NM interventions. In another subgroup analysis, NM used exhibited a significantly lower risk of bleeding complications than those of the low-molecular-weight heparin (LMWH) used (RR = 4.58, p = 0.020). The filter lifespan was decreased significantly (MD = -10.59, p < 0.0001) in the NA groups compared with the NM groups. Due to the poor quality of the included RCTs, these results should be interpreted with caution.

CONCLUSION

Given the better survival outcomes, lower risk of bleeding, NM anticoagulation seems to be a safe and efficient approach for BPT patients and could yield a favorable filter lifespan. More multi-center RCTs with large samples are required for further validation of this study.

Results of the 2018 Japan Society for Blood Purification in Critical Care survey: current status and outcomes

Background

The Japan Society for Blood Purification in Critical Care (JSBPCC) has reported survey results on blood purification therapy (BPT) for critically ill patients in 2005, 2009, and 2013. To clarify the current clinical status, including details of the modes used, treated diseases, and survival rate, we conducted this cohort study using data from the nationwide JSBPCC registry in 2018.

Methods

We analyzed data of 2371 patients who underwent BPT in the intensive care units of 43 facilities to investigate patient characteristics, disease severity, modes of BPTs, including the dose of continuous renal replacement therapy (CRRT) and hemofilters, treated diseases, and the survival rate for each disease. Disease severity was assessed using Acute Physiology and Chronic Health Evaluation (APACHE) II and Sequential Organ Failure Assessment (SOFA) scores.

Results

BPT was performed 2867 times in the 2371 patients. Mean APACHE II and SOFA scores were 23.5 ± 9.4 and 10.0 ± 4.4, respectively. The most frequently used mode of BPT was CRRT (67.4%), followed by intermittent renal replacement therapy (19.1%) and direct hemoperfusion with the polymyxin B-immobilized fiber column (7.3%). The most commonly used anticoagulant was nafamostat mesilate (78.6%). Among all patients, the 28-day survival rate was 61.7%. CRRT was the most commonly used mode for many diseases, including acute kidney injury (AKI), multiple organ failure (MOF), and sepsis. The survival rate decreased according to the severity of AKI (P = 0.001). The survival rate was significantly lower in patients with multiple organ failure (MOF) (34.6%) compared with acute lung injury (ALI) (48.0%) and sepsis (58.0%). Multivariate logistic regression analysis revealed that sepsis, ALI, acute liver failure, cardiovascular hypotension, central nervous system disorders, and higher APACHE II scores were significant predictors of higher 28-day mortality.

Conclusion

This large-scale cohort study revealed the current status of BPT in Japan. It was found that CRRT was the most frequently used mode for critically ill patients in Japan and that 28-day survival was lower in those with MOF or sepsis. Further investigations are required to clarify the efficacy of BPT for critically ill patients.

Trial Registration: UMIN000027678.

Filter lifetimes of different hemodiafiltration membrane materials in dogs: reevaluation of the optimal anticoagulant dosage

Background

In continuous renal replacement therapy (CRRT), administration of anticoagulants is necessary for achieving a certain level of filter lifetime. Generally, anticoagulant doses are controlled to keep activated partial thromboplastin time and other indicators within a certain target range, regardless of the membrane materials used for the filter. However, in actual clinical practice, the filter lifetime varies significantly depending on the membrane material used. The objective of this study was to demonstrate that the minimum anticoagulant dose necessary for prolonging the filter lifetime while reducing the risk of hemorrhagic complications varies depending on the type of membrane.

Methods

In three beagles, hemodiafiltration was performed with hemofilters using polysulfone (PS), polymethylmethacrylate (PMMA), and AN69ST membranes separately. The minimum dose of nafamostat mesylate (NM) that would allow for 6 h of hemodiafiltration (required dose) was investigated for each membrane material.

Results

The NM doses required for 6 h of hemodiafiltration were 2 mg/kg/h for the PS membrane, 6 mg/kg/h for the PMMA membrane, and 6 mg/kg/h for the AN69ST membrane.

Conclusion

For hemodiafiltration performed in beagles, the required NM dose varied for each filter membrane material. Using the optimal anticoagulant dose for each membrane material would allow for safer CRRT performance.

Blood purification therapy for severe sepsis: a multicenter, observational cohort study in northern Japan

Background

Sepsis is associated with life-threatening organ dysfunction caused by a dysregulated host response to infection. However, no specific therapy has been shown to improve mortality in patients with sepsis. We conducted a study to clarify the utilization status of various BPTs and the clinical characteristics of patients who received BPTs in northern Japan. In addition, the association of various BPTs with clinical outcomes was examined.

Methods

This is a sub-analysis of the Tohoku Sepsis Registry, a multicenter, prospective, observational cohort study. To determine whether BPT was independently associated with in-hospital mortality in patients with severe sepsis, the following analyses were performed. Differences between survivors and non-survivors were assessed using Wilcoxon rank sum tests for continuous variables and Chi-square tests for categorical variables. Univariate logistic regression analysis was used to evaluate the factors associated with in-hospital mortality. In the multivariate logistic regression analysis, adjustments were made for the variables that were significant in the univariate logistic regression analysis. Clinical factors associated with mortality were analyzed.

Results

We enrolled 616 consecutive patients (≥ 18 years) with median Sequential Organ Failure Assessment scores of 8.0. During median of 22 days hospitalization, 139 patients died (mortality 22.6%). 20.7% of patients with severe sepsis received any type of BPT (mortality 38.6%). BPT consisted of 65.1% continuous renal replacement therapy (CRRT) with renal indication (mortality 48.8%), 26.0% CRRT with non-renal indication (mortality 21.2%), 22.2% intermittent renal replacement therapy (mortality 32.1%), and 33.1% polymyxin B-immobilized fiber column-direct hemoperfusion (mortality 42.9%). Meanwhile, no BPT group (mortality 18.5%) showed a significantly lower mortality than any BPT group. Besides, in multivariate analyses, all BPT modes were not independently associated with all-cause mortality.

Conclusions

This study suggested the clinical status of BPTs for severe sepsis patients in northern Japan. Among all types of BPT, continuous renal replacement therapy (CRRT) for renal indication was most frequently selected. Severe sepsis patients received BPT had a higher mortality and severity; however, the BPT implementation may not be associated with mortality.

Trial registration UMIN-CTR, UMIN000010297, Registered on 22 March 2013, https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000012055).

Targeting Cytokines, Pathogen-Associated Molecular Patterns, and Damage-Associated Molecular Patterns in Sepsis via Blood Purification

Sepsis is characterized by a dysregulated immune response to infections that causes life-threatening organ dysfunction and even death. When infections occur, bacterial cell wall components (endotoxin or lipopolysaccharide), known as pathogen-associated molecular patterns, bind to pattern recognition receptors, such as toll-like receptors, to initiate an inflammatory response for pathogen elimination. However, strong activation of the immune system leads to cellular dysfunction and ultimately organ failure. Damage-associated molecular patterns (DAMPs), which are released by injured host cells, are well-recognized triggers that result in the elevation of inflammatory cytokine levels. A cytokine storm is thus amplified and sustained in this vicious cycle. Interestingly, during sepsis, neutrophils transition from powerful antimicrobial protectors into dangerous mediators of tissue injury and organ dysfunction. Thus, the concept of blood purification has evolved to include inflammatory cells and mediators. In this review, we summarize recent advances in knowledge regarding the role of lipopolysaccharides, cytokines, DAMPs, and neutrophils in the pathogenesis of sepsis. Additionally, we discuss the potential of blood purification, especially the adsorption technology, for removing immune cells and molecular mediators, thereby serving as a therapeutic strategy against sepsis. Finally, we describe the concept of our immune-modulating blood purification system.

Effects of continuous renal replacement therapy with the AN69ST membrane for septic shock and sepsis-induced AKI in an infant: a case report with literature review of cytokine/mediator removal therapy in children

Background

Septic shock is a life-threatening condition and one of the most common causes of acute kidney injury (AKI). The acrylonitrile-co-methallyl sulfonate surface-treated (AN69ST) membrane used in severe sepsis was formally launched in Japan in 2014, as a non-renal indication. This membrane provides hemofiltration in dialysis and improves hemodynamics in patients with sepsis and hypercytokinemia. However, the clinical literature regarding continuous renal replacement therapy (CRRT) with the AN69ST membrane is very limited, especially in infants.

Case presentation

A 3-month-old female infant weighing 4.2 kg was hospitalized for septic shock and AKI secondary to necrotizing enterocolitis. Although she underwent palliative surgery, her vital signs did not recover from shock, and she developed reduced urine output. Her pediatric sequential organ failure assessment score was 10 points. Thus, we strongly suspected septic shock and sepsis-induced AKI, which were refractory to conservative treatment, and we decided to introduce CRRT with the AN69ST membrane for both renal replacement and anti-hypercytokinemic indications. After initiating CRRT for 72 h, her blood pressure increased sufficiently to maintain urine output, and improvements in the electrolyte abnormalities and metabolic acidosis were observed. Notably, her serum inflammatory cytokine levels decreased in parallel with improvement in her general condition. Despite successfully recovering from the AKI and being stable enough to allow discontinuing CRRT, she died of multiple organ dysfunction syndrome 3 weeks after CRRT was discontinued.

Conclusions

CRRT may complement standard treatment in patients with sepsis-induced AKI to control the amplitude of the systemic inflammatory response regarding acute tissue and organ damage. We expect that CRRT with the AN69ST membrane will be recognized as an option for the treatment of septic shock and sepsis-induced AKI, even in infants.

RRT Selection for AKI Patients With Critical Illness

Acute kidney injury (AKI) is a critical burden on intensive care units in Asia. Renal replacement therapy (RRT) acts as strong supportive care for severe AKI. However, various RRT modalities are used in Asia because of the diversity in ethics, climate, geographic features, and socioeconomic status. Extracorporeal blood purification is used commonly in Asian intensive care units; however, intermittent RRT is preferred in developing countries because of cost and infrastructure issues. Conversely, continuous RRT is preferred in developed countries, indicating the predominance of hospital-acquired AKI patients with complications of hemodynamic instability. Peritoneal dialysis is delivered less frequently, although several studies have suggested promising results for peritoneal dialysis in AKI treatment. Of note, not all RRT modalities are available as a standard procedure in some Asian regions, and it is absolutely necessary to develop a sustainable infrastructure that can deliver optimal care for all AKI patients.

Nafamostat Mesylate Improved Survival Outcomes of Sepsis Patients Who Underwent Blood Purification: A Nationwide Registry Study in Japan

Nafamostat mesylate (NM) is a synthetic serine protease inhibitor that can be used as an anticoagulant during blood purification in critically ill patients, as well as a treatment for disseminated intravascular coagulation. Although NM has been reported to reduce the risk of bleeding during blood purification, its effect on survival outcomes of patients who received blood purification treatments is unclear. We hypothesized that administration of NM during blood purification can reduce mortality in patients with sepsis. A post hoc analysis was conducted on a nationwide retrospective registry that included data from 3195 sepsis patients registered at 42 intensive care units throughout Japan. We evaluated the effect of NM on hospital mortality and bleeding complications using propensity score matching in 1216 sepsis patients who underwent blood purification in the intensive care unit (ICU). Two-hundred-and-sixty-eight pairs of propensity score-matched patients who received NM and conventional therapy were compared. Hospital and ICU mortality rates in the NM group were significantly lower than those in the conventional therapy group. However, rates of bleeding complications did not differ significantly between the two groups. These data suggest that administration of NM improved the survival outcomes of sepsis patients who underwent blood purification in the ICU.

Involvement of ionic interactions in cytokine adsorption of polyethyleneimine-coated polyacrylonitrile and polymethyl methacrylate membranes in vitro

Polyethyleneimine-coated polyacrylonitrile (AN69ST) and polymethyl methacrylate (PMMA) membranes are effective cytokine-adsorbing hemofilters; however, the cytokine-adsorption mechanism remains elusive. This study investigated the involvement of ionic interactions in cytokine adsorption to a negatively charged AN69ST membrane and neutral-charged PMMA membrane. Experimental hemofiltration was performed for 30 min in a closed-loop circulation system using AN69ST and PMMA hemofilters. Tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-8 concentrations in the test solutions were measured at baseline and at 10 min and 30 min into hemofiltration. To investigate the involvement of ionic interactions in cytokine adsorption, cytokine clearance (CL) was calculated at 10 min into hemofiltration and with three types of solutions at various pH levels (7.6, 7.2, and 6.8). During AN69ST hemofiltration, the CLs of TNF-α, IL-6, and IL-8 were 38 ± 6 mL/min, 23 ± 7 mL/min, and 78 ± 3 mL/min, respectively, demonstrating a relationship with their respective isoelectric points. During PMMA hemofiltration, the CL of IL-6 peaked at 31 ± 76 mL/min, with no relationship observed between the CL and isoelectric point. When the pH of the test solution shifted from 7.6 to 6.8, the CLs of TNF-α, IL6, and IL-8 increased in the AN69ST hemofilter; whereas, no such trend was observed in the PMMA hemofilter. These results indicated that Ionic interactions play a role in cytokine adsorption by the AN69ST membrane but not the PMMA membrane and highlight the clinical relevance of this finding, as well as the potential practical applications for further hemofilter design.