Efficacy of therapeutic plasma exchange in a case of severe, generalised canine pemphigus foliaceus.

Successful treatment of pemphigus foliaceus (PF) often requires a multimodal therapeutic approach. The dog described herein underwent four therapeutic plasma exchange treatments for severe, refractory PF, resulting in a 50% reduction of lesional body surface area. This treatment option should be considered for the management of canine PF.

O tratamento bem-sucedido do pênfigo foliáceo (PF) geralmente requer uma abordagem terapêutica multimodal. O cão aqui descrito foi submetido a quatro tratamentos de troca de plasma terapêutica (TPE) para PF grave e refratário, resultando em uma redução de 50% da área corpórea lesional. Esta opção de tratamento deve ser considerada para o manejo do PF canino.

El tratamiento exitoso del pénfigo foliáceo (PF) a menudo requiere un enfoque terapéutico multimodal. El perro aquí descrito se sometió a cuatro tratamientos terapéuticos de intercambio plasmático (TPE) para un PF refractario grave, lo que resultó en una reducción del 50% de la superficie corporal lesionada. Esta opción de tratamiento debe considerarse para el control de PF canino.

Traiter efficacement le pemphigus foliacé (PF) nécessite souvent une approche thérapeutique multimodale. Dans ce rapport clinique, un chie a reçu quatre traitements de plasmaphérèse thérapeutique (EPT) pour le traitement d'un PF sévère et réfractaire, ce qui a permis de réduire de 50 % la surface corporelle lésionnelle. Cette option thérapeutique devrait être envisagée pour la prise en charge du PF canin.

Septic Hyperinflammation-Is There a Role for Extracorporeal Blood Purification Techniques?

This manuscript investigates the role of extracorporeal blood purification techniques in managing septic hyperinflammation, a critical aspect of sepsis characterized by an uncontrolled immune response leading to multiorgan dysfunction. We provide an overview of sepsis, focusing on the dynamics of immune response, the involvement of neutrophils, and the role of the endothelium in the disease's progression. It evaluates the effectiveness of various blood purification methods, including high-cut-off membranes, high-volume hemofiltration, adsorption techniques, and albumin dialysis, in removing cytokines and endotoxin and improving hemodynamic stability. Despite some very promising results, we conclude that the current evidence does not strongly support these techniques in significantly improving survival rates in septic patients, clearly underlining the need for further research.

Survival benefit of resin cartridge extracorporeal blood purification therapy in patients with septic shock.

Background/aim: Extracorporeal blood purification (EBP) therapies have shown promise as potential rescue treatments for patients with septic shock. However, precise evidence regarding their effectiveness is lacking. This case-control study aimed to evaluate the 28-day survival benefit of a resin cartridge-based EBP therapy compared to conventional therapies in patients with septic shock. Materials and methods: The study sample was collected retrospectively from the medical records of patients admitted to the intensive care unit (ICU) between 2015 and 2020. The study included patients with septic shock aged ≥18 years who had ICU stays >96 h and excluded those lost to follow-up by 28 days or readmitted. First, 28-day survival was compared between EBP patients and 1:1 matched conventionally treated controls. Second, the EBP patients were evaluated for clinical and laboratory improvements within 72 h of EBP therapy. Results: Of 3742 patients, 391 were included in this study, of whom 129 received EBP therapy and had a 28-day survival rate of 44%, compared to 262 matched controls who received conventional therapy alone and had a survival rate of 33% (p = 0.001, log-rank = 0.05, number needed to treat = 8, and odds ratio = 1.7). After receiving EBP therapy for 72 h, improvements were observed in the Sequential Organ Failure Assessment scores (p < 0.05), shock indices (p < 0.05), partial pressure of oxygen in the arterial blood to the fraction of inspiratory oxygen concentration ratios (p < 0.001), vasopressor requirements (p < 0.001), pH (p < 0.05), lactate levels (p < 0.001), and C-reactive protein levels (p < 0.05). Conclusion: The findings suggest that administering resin cartridge-based EBP therapy to patients with septic shock may improve their survival compared to conventional therapies.

CytoSorb hemoperfusion markedly attenuates circulating cytokine concentrations during systemic inflammation in humans in vivo.

BACKGROUND: The CytoSorb hemoadsorption device has been demonstrated to be capable of clearing inflammatory cytokines, but has not yet been shown to attenuate plasma cytokine concentrations. We investigated the effects of CytoSorb hemoperfusion on plasma levels of various cytokines using the repeated human experimental endotoxemia model, a highly standardized and reproducible human in vivo model of systemic inflammation and immunological tolerance induced by administration of bacterial lipopolysaccharide (LPS). METHODS: Twenty-four healthy male volunteers (age 18-35) were intravenously challenged with LPS (a bolus of 1 ng/kg followed by continuous infusion of 0.5 ng/kg/hr for three hours) twice: on day 0 to quantify the initial cytokine response and on day 7 to quantify the degree of endotoxin tolerance. Subjects either received CytoSorb hemoperfusion during the first LPS challenge (CytoSorb group), or no intervention (control group). Plasma cytokine concentrations and clearance rates were determined serially. This study was registered at ClinicalTrials.gov (NCT04643639, date of registration November 24th 2020). RESULTS: LPS administration led to a profound increase in plasma cytokine concentrations during both LPS challenge days. Compared to the control group, significantly lower plasma levels of tumor necrosis factor (TNF, - 58%, p < 0.0001), interleukin (IL)-6 ( - 71%, p = 0.003), IL-8 ( - 48%, p = 0.02) and IL-10 ( - 26%, p = 0.03) were observed in the CytoSorb group during the first LPS challenge. No differences in cytokine responses were observed during the second LPS challenge. CONCLUSIONS: CytoSorb hemoperfusion effectively attenuates circulating cytokine concentrations during systemic inflammation in humans in vivo, whereas it does not affect long-term immune function. Therefore, CytoSorb therapy may be of benefit in conditions characterized by excessive cytokine release.

Extracorporeal therapy of sepsis by purified granulocyte concentrates: ex vivo circulation model.

BACKGROUND: Immune cell dysfunction is a central part of immune paralysis in sepsis. Granulocyte concentrate (GC) transfusions can induce tissue damage via local effects of neutrophils. The hypothesis of an extracorporeal plasma treatment with granulocytes is to show beneficial effects with fewer side effects. Clinical trials with standard GC have supported this approach. This ex vivo study investigated the functional properties of purified granulocyte preparations during the extracorporeal plasma treatment. METHODS: Purified GC were stored for up to 3 days and compared with standard GC in an immune cell perfusion therapy model. The therapy consists of a plasma separation device and an extracorporeal circuit. Plasma is perfused through the tubing system with donor immune cells of the GC, and only the treated plasma is filtered for re-transfusion. The donor immune cells are retained in the extracorporeal system and discarded after treatment. Efficacy of granulocytes regarding phagocytosis, oxidative burst as well as cell viability and metabolic parameters were assessed. RESULTS: In pGC, the metabolic surrogate parameters of cell functionality showed comparable courses even after a storage period of 72 h. In particular, glucose and oxygen consumption were lower after extended storage. The course of lactate dehydrogenase concentration yields no indication of cell impairment in the extracorporeal circulation. The cells were viable throughout the entire study period and exhibited preserved phagocytosis and oxidative burst functionality. CONCLUSION: The granulocytes demonstrated full functionality in the 6 h extracorporeal circuits after 3 days storage and in septic shock plasma. This is demonstrating the functionality of the system and encourages further clinical studies.

Efficacy and Safety of a Low-Flow Extracorporeal Carbon Dioxide Removal System in Acute Respiratory Failure, a Pilot Study in China.

BACKGROUND: Low-flow extracorporeal carbon dioxide removal (LF-ECCO2R) has the potential to play an important role in the management of adults with acute respiratory failure. However, it has never been tested in China. The study aimed at exploring the safety and efficacy on LF-ECCO2R for acute respiratory failure in a Chinese tertiary intensive care unit (ICU). MATERIALS AND METHODS: We performed a retrospective case note review of patients admitted to our tertiary regional ICU and commenced on LF-ECCO2R from June 2020 to September 2021. The LF-ECCO2R device we used was ProLUNG® system (Estor S.p.A., Milan, Italy). The device employed a nonporous poly-4-methyl-1-pentene membrane lung with a surface area of 1.81 m2 and run at an extracorporeal blood flow between 100 and 450 mL/min. Demographic and physiologic data (including ventilation parameters and arterial blood gases) as well as the outcome of LF-ECCO2R treatment were recorded. RESULTS: A total of 12 cases were included. A statistically significant reduction in respiratory rate, driving pressure, PaCO2, and blood lactate was observed. In addition, there was a statistically significant improvement in pH and PaO2/FiO2. Six out of 12 patients (50%) were discharged alive from ICU. Three complications related to LF-ECCO2R were reported, none resulting in serious adverse outcomes. CONCLUSION: Our clinical series indicated that LF-ECCO2R seemed to be safely applied in patients with acute respiratory failure. The efficacy of CO2 removal as well as the improved respiratory parameters was also observed. However, large-scale randomized clinical trials are needed to confirm the effects.

Continuous Renal Replacement Therapy during Extracorporeal Membrane Oxygenation: Circuit Haemodynamics and Circuit Failure.

INTRODUCTION: Treatment with continuous renal replacement therapy (CRRT) is common during extracorporeal membrane oxygenation (ECMO). Such ECMO-CRRT has specific technical characteristics, which may affect circuit life. Accordingly, we studied CRRT haemodynamics and circuit life during ECMO. METHODS: ECMO and non-ECMO-CRRT treatments in two adult intensive care units were compared using data collected over a 3-year period. A potential predictor of circuit survival identified in a 60% training data subset as a time-varying covariate within a Cox proportional hazard model was subsequently assessed in the complementary remaining data (40%). RESULTS: Median [interquartile range] CRRT circuit life was greater when associated with ECMO (28.8 [14.0-65.2] vs. 20.2 [9.8-40.2] h, p < 0.0001). Access, return, prefilter, and effluent pressures were also greater during ECMO. Higher ECMO flows were associated with higher access and return pressures. Classification and regression tree analysis identified an association between high access pressures and accelerated circuit failure, while both first access pressures ≥190 mm Hg (HR 1.58 [1.09-2.30]) and patient weight (HR 1.85 [1.15-2.97] third tertile vs. first tertile) were independently associated with circuit failure in a multivariable Cox model. Access dysfunction was associated with a stepwise increase in transfilter pressure, suggesting a potential mechanism of membrane injury. CONCLUSION: CRRT circuits used in conjunction with ECMO have a longer circuit life than usual CRRT despite exposure to higher circuit pressures. Markedly elevated access pressures, however, may predict early CRRT circuit failure during ECMO, possibly via progressive membrane thrombosis as evidenced by increased transfilter pressure gradients.

Plasma exchange in ANCA-associated vasculitis: the pro position.

Plasma exchange (PLEX) is capable of removing significant amounts of circulating antibodies. In anti-neutrophil cytoplasmic antibody-associated vasculitis, PLEX was reserved for patients with severe presentation forms such as rapidly progressive glomerulonephritis and pulmonary haemorrhage. The Plasma Exchange and Glucocorticoids in Severe ANCA-Associated Vasculitis (PEXIVAS) trial included all comers with a glomerular filtration rate <50 mL/min/1.73 m2 and thus aimed to answer the question of whether PLEX is an option for patients with no relevant kidney function impairment or not. PEXIVAS revealed that after a follow-up of almost 3 years, routine administration of PLEX does not provide an additional benefit to reduce the rate of a composite comprising end-stage kidney disease or death. In the absence of histological parameters, it is tempting to speculate whether PLEX is effective or not in those with a potential for renal recovery. A subset of patients presented with alveolar haemorrhage, and there was a trend towards a better outcome of such cases receiving PLEX. This would be in line with observational studies reporting a recovery of alveolar haemorrhage following extracorporeal treatment. In this PRO part of the debate, we highlight the shortcomings of the PEXIVAS trial and stimulate further research paths, which in our eyes are necessary before abandoning PLEX from the therapeutic armamentarium.

Heparin 2.0: A New Approach to the Infection Crisis.

In April 2020, the US Food and Drug Administration granted emergency use authorization for certain medical devices to be used in patients with coronavirus disease 2019 (CO-VID-19). This included extracorporeal blood purification devices. This narrative review will give a brief overview regarding some of the extracorporeal devices that could be used to treat COVID-19 patients, including the Seraph® 100 Microbind® Affinity Blood Filter, produced by ExThera Medical (Martinez, CA, USA), first licensed in the European Economic Area in 2019. The Seraph® 100 contains ultrahigh molecular weight polyethylene beads with end point-attached heparin and is approved for the reduction of pathogens from the bloodstream either as a single agent or as an adjunct to conventional anti-infective agents. Bacteria, viruses, fungi, and toxins have been shown to bind to the immobilized heparin in a similar way to the interaction with heparan sulfate on the cell surface. This binding is nonreversible and as such, the pathogens are removed from the bloodstream. In this review, we describe the pathophysiological basis and rationale for using heparin for pathogen removal from the blood as well as exploring the technology behind the adaptation of heparin to deprive it of its systemic anticoagulant activity. In addition, we summarize the in vitro data as well as the available preclinical testing and published clinical reports. Finally, we discuss the enormous potential of this technology in an era of increasing antibiotic resistance and high mortality associated with sepsis and consider the application of this as a possible treatment option for COVID-19.

Acute Kidney Injury, Fluid Overload, and Renal Replacement Therapy Differ by Underlying Diagnosis in Neonatal Extracorporeal Support and Impact Mortality Disparately.

INTRODUCTION: We aimed to characterize acute kidney injury (AKI), fluid overload (FO), and renal replacement therapy (RRT) utilization by diagnostic categories and examine associations between these complications and mortality by category. METHODS: To test our hypotheses, we conducted a retrospective multicenter, cohort study including 446 neonates (categories: 209 with cardiac disease, 114 with congenital diaphragmatic hernia [CDH], 123 with respiratory disease) requiring extracorporeal membrane oxygenation (ECMO) between January 1, 2007, and December 31, 2011. RESULTS: AKI, FO, and RRT each varied by diagnostic category. AKI and RRT receipt were most common in those neonates with cardiac disease. Subjects with CDH had highest peak %FO (51% vs. 28% cardiac vs. 32% respiratory; p < 0.01). Hospital survival was 55% and varied by diagnostic category (45% cardiac vs. 48% CDH vs. 79% respiratory; p < 0.001). A significant interaction suggested risk of mortality differed by diagnostic category in the presence or absence of AKI. In its absence, diagnosis of CDH (vs. respiratory disease) (OR 3.04, 95% CL 1.14-8.11) independently predicted mortality. In all categories, peak %FO (OR 1.20, 95% CL 1.11-1.30) and RRT receipt (OR 2.12, 95% CL 1.20-3.73) were independently associated with mortality. DISCUSSION/CONCLUSIONS: Physiologically distinct ECMO diagnoses warrant individualized treatment strategies given variable incidence and effects of AKI, FO, and RRT by category on mortality.

Therapeutic Plasma Exchange with Continuous Renal Replacement Therapy for Pediatric Acute Liver Failure: A Case Series from Thailand.

AIM AND OBJECTIVE: Pediatric acute liver failure (PALF) is a life-threatening condition. Extracorporeal support has been applied for toxic metabolite clearance and serves as a bridging therapy to liver transplantation (LT) or to the regeneration of the liver, but evidence for treatment approaches is still lacking in the pediatric population. We aim to report our experience on therapeutic plasma exchange with high-volume continuous renal replacement therapy (TPE + HV-CRRT) as a promising supportive treatment for PALF. MATERIALS AND METHODS: A total of eight PALF cases aged 9 months to 14 years, weighing 10-50 kg., who were admitted to PICU King Chulalongkorn Memorial Hospital, Thailand and treated with TPE + HV-CRRT from January 2016 to September 2019 were reviewed. Patient demographic data, indications, technical aspects, and clinical outcomes were recorded. RESULTS: All patients who underwent TPE + HV-CRRT showed clinical improvement regarding serum bilirubin levels and coagulation studies after the therapy. Complications from the therapy were hemodynamic instability, symptomatic fluid overload, and bleeding from catheter sites. Among these, 6 (75%) patients survived with 4 (50%) successful LTs and 2 (25%) spontaneous recovery. Two children (25%) died while on the transplantation list. CONCLUSION: TPE + HV-CRRT can be used safely as a bridging therapy in children with PALF. As opposed to the adult population, higher volume of TPE or higher blood flow rate in pediatric patients might associate with hemodynamic instability during the procedure. HOW TO CITE THIS ARTICLE: Trepatchayakorn S, Chaijitraruch N, Chongsrisawat V, Chanakul A, Kongkiattikul L, Samransamruajkit R. Therapeutic Plasma Exchange with Continuous Renal Replacement Therapy for Pediatric Acute Liver Failure: A Case Series from Thailand. Indian J Crit Care Med 2021;25(7):812-816.

The golden hour of polymyxin B hemoperfusion in endotoxic shock: The basis for sequential extracorporeal therapy in sepsis.

Endotoxin is recognized as a major trigger of the immune response leading to pro- and anti-inflammatory cytokine release, activation of the coagulation cascade, vasoplegic shock, and multiple organ dysfunction syndrome. A beneficial effect could be achieved through extracorporeal adsorption of circulating endotoxins in the blood as adjunctive treatment for unresponsive endotoxic shock. However, the precise clinical indication for its initiation is widely debated in the literature. Similar to the source control, microbiological cultures and antibiotics administration, endotoxin activity assay evaluation at regular intervals, and the targeted use of PMX-B hemoperfusion could be lifesaving and adequate within the golden hour for the diagnosis and treatment of endotoxic shock.

Extracorporeal Therapies in the Treatment of Focal Segmental Glomerulosclerosis.

Focal segmental glomerulosclerosis (FSGS) is one of the most frequent and severe glomerular kidney disease with frequent progression to end-stage renal disease and a high rate of recurrence in renal transplantations. Due to intolerance or resistance to the current immunomodulatory treatments, the management of FSGS is a therapeutic challenge. Over the last few years, development in extracorporeal therapies has shown potential beneficial outcomes in drug-resistant and recurrent FSGS patients. Thus, this study reviews the current literature on the use of extracorporeal therapies, such as plasma exchange therapy, immunoadsorption, and low-density lipoprotein apheresis, for the treatment of FSGS in the pediatric population.

Sequential Extracorporeal Therapy Collaborative Device and Timely Support for Endotoxic, Septic, and Cardiac Shock: A Case Report.

We report a 49-year-old man, without prior medical history, consulted in the emergency department with a 5 day history of cough, fever, and dysuria. He was admitted to the intensive care unit due to septic shock. Critical care management was initiated, including mechanical ventilation and vasopressors. Endotoxic shock was suspected (endotoxin activity assay [EAA] 0.75), and 2 treatments with Polymyxin B hemoperfusion (Toraymyxin®, Toray Medical Co., Ltd., Tokyo, Japan) were performed in 48 h, alternate with high-volume hemofiltration sessions. Initial blood cultures were positive for Neisseria meningitidis (serogroup B), and a lumbar puncture was deferred because of the coagulopathy and a bleeding risk. The circulatory efficiency significantly improved after the second procedure of hemoperfusion, and the treatment resulted in a marked decrease in the serum endotoxin level (EAA <0.4). However, after 48 h, tachycardia did not improve, left ventricular ejection fraction was 20%, and circulatory insufficiency progressed. Therefore, considering the involvement of septic cardiomyopathy and cardiogenic shock, veno-arterial extracorporeal membrane oxygenation (VA-ECMO) was initiated for circulation assistance on day 3 from admission. Continuous cytokine hemoadsorption (Cytosorb®, Cytosorbent Corporation, Monmouth Junction, NJ, USA) was incorporated into a VA-ECMO circuit for 48 h without a considerable improvement. For this reason, a 72-h continuous veno-venous hemodialysis session was started in which a high cutoff filter was used. Tachycardia and myocardial dysfunction improved by day 6, and VA-ECMO was withdrawn on the tenth day. Subsequently, nutrition management and rehabilitation were performed, and the patient was transferred to the department of respiratory medicine on day 80, he was discharged from our hospital on day 113. Sequential extracorporeal therapy may be beneficial when concomitant with circulatory assistance in uncontrollable cases of septic shock using catecholamines and blockers.

High-efficiency, high-flux in-line hemofiltration using a high blood flow extracorporeal circuit.

The ability of current renal replacement therapy modalities to achieve rapid solute removal is limited by membrane surface area and blood flow rate. Extracorporeal membrane oxygenation offers high blood flow and hemodynamic support that may be harnessed to overcome limitations in traditional renal replacement therapy. Using an extracorporeal membrane oxygenation circuit, we describe a high blood flow, high-efficiency hemofiltration technique using in-line hemofilters (hemoconcentrators) and standard replacement fluid to enhance solute clearance. Using this approach and a total of 5 L of replacement volume per treatment, creatinine (Cr) clearances of 8.3 L/hour and 11.2 L/hour using one and two hemoconcentrators, respectively, were achieved. With use of a high blood flow rate of up to 5 L/min, this hemofiltration technique can potentially offer clearance of 30 times that of continuous renal replacement therapy and of 6 times that of hemodialysis which may expand the ability to remove substances traditionally not considered removable via existing extracorporeal therapies.

Extracorporeal Therapy in Sepsis.

How to cite this article: Govil D, Kumar GP. Extracorporeal Therapy in Sepsis. Indian J Crit Care Med 2020;24(Suppl 3):S117-S121.

A New Series of Sorbent Devices for Multiple Clinical Purposes: Current Evidence and Future Directions.

Adsorption is an extracorporeal technique utilized for blood purification. It complements convection and diffusion (the main modalities of solute removal). It involves the passage of blood (or plasma) through an adsorption cartridge, where solutes are removed by direct binding to the sorbent material. Over the years, new adsorption cartridges, with improved characteristics have been developed. Furthermore, the therapeutic applications of adsorption have expanded. These now involve the treatment of inflammatory conditions, chronic uremic symptoms, and autoimmune disease, in addition to intoxication, which was once considered the classical indication for adsorption therapy. HA130, HA230, and HA330 (Jafron, Zhuhai City, China) are among the widely used adsorption cartridges in China. There has been sufficient body of evidence to support their effectiveness and safety. In this review, we aim to highlight their main clinical applications.

What Have We Learned about the Use of Cytosorb Adsorption Columns?

Extracorporeal blood purification techniques have emerged and evolved in the recent years as a potential therapy for the purpose of immunomodulation in acute conditions like sepsis. Understanding the extent of immune system dysregulation involved in the pathophysiology of these conditions, resulted in the development of such treatment strategies aiming at restoring a balanced inflammatory response. Beyond conventional continuous renal replacement therapy, high volume hemofiltration, high cut-off membranes, adsorption alone and coupled plasma filtration adsorption are well-described techniques in the literature. The evidence to support their routine use, however, is conflicting and insufficient at this stage. Despite the low-quality level of evidence in favor of utilizing these techniques, studies to further explore their effectiveness, safety, and potential novel applications, continue to evolve. Our review aims at focusing on adsorption therapy, particularly using the adsorption columns Cystosorb.

Feasibility of hemoperfusion using extracorporeal therapy in the horse.

Objective: Develop, implement, and monitor for adverse effects of, a novel hemoperfusion therapy in adult horses. Methods: A prospective, observational feasibility study using three healthy adult horses from the North Carolina State University teaching herd. Health status was determined by physical exam, complete blood count, coagulation panel, and serum biochemistry. Each horse was instrumented with a 14 Fr × 25 cm double-lumen temporary hemodialysis catheter and underwent a 240 min polymer-based hemoperfusion session. Horses were administered unfractionated heparin to maintain anti-coagulation during the session. Given the novelty of this therapy in horses, each horse was treated as a learning opportunity that informed an iterative process of protocol development and modification. Measurements and main results: Our long-term goal is to investigate potential clinical applications of hemoperfusion in horses, including cytokine reduction in horses with severe SIRS/sepsis. Horses were monitored for changes in clinical exam, biochemistry and hematology parameters. Additionally, cytokines were quantified to determine whether extracorporeal hemadsorption therapy alone caused an inflammatory response. Our results show that hemoperfusion therapy was associated with decreased platelet counts and serum albumin concentration. There was no significant change in plasma cytokine concentrations with hemoperfusion therapy. In one horse, the cytokine concentrations decreased, as previously reported with hemoperfusion therapy in humans. Hypothesis: We hypothesized that hemoperfusion therapy could be performed in healthy adult horses without significant adverse effects. Conclusion: Polymer-based hemoperfusion is a feasible extracorporeal therapy (ECT) modality for adult horses. Additional studies are needed to further establish clinical protocols, as well as establish efficacy of polymer-based hemoperfusion for treatment of various conditions in horses, including intoxications, immune-mediated conditions, and sepsis.

Using the Seraph® 100 Microbind® Affinity blood filter under slow flow conditions through 18 G and 16 G central lines.

INTRODUCTION: The Seraph® 100 Microbind® Affinity blood filter (Seraph® 100) has been in use since 2019 for the treatment of fulminant or difficult to treat blood stream infections as an adjunct to pharmacotherapy. In 2020 the device received emergency use authorization by the US Food and Drug Administration for the treatment of critically ill COVID-19 patients with confirmed or imminent respiratory failure. Results of an international registry showed that the Seraph® 100 was operated under blood flow rates of 100-350 mL/min. As those conditions require a large bore central line, a dialysis catheter is currently considered indispensable to operate the Seraph® 100. The use of smaller catheter lumina has neither been evaluated in vitro nor in vivo. METHODS: In vitro pressure data before and after the Seraph® 100 at various blood pump rates (prepump line 16 G, postpump line 18 G) with saline and human plasma were obtained. Further, anecdotal flow and pressure data of two patients treated with the Seraph® 100 for a COVID-19 infection are reported. RESULTS: At a pump speed of 50 mL/min pre-Seraph® pressure using saline was -70 [-70 to -60] mm Hg. In comparison, using plasma pre-Seraph® pressure was lower at -120 [-120 to -105] mm Hg; p < 0.001 (t-test). The post-Seraph® pressure at 50 mL/min using saline of 120 [110-130] mm Hg was not different from plasma at 130 [120-140] mm Hg, p = 0.152 (t-test). Blood flow rates of 50 mL/min did not lead to preAP levels below -250 mm Hg in the two clinical cases. CONCLUSION: Seraph® 100 blood flow rate of 50 mL/min may be achieved using low flow vascular access, allowing to treat a blood volume 72 L in 24 h.