Elimination of Staphylococcus aureus from the bloodstream using a novel biomimetic sorbent haemoperfusion device

[Extracorporeal removal of pathogens using a biomimetic adsorber-A new treatment strategy for the intensive care unit : Seraph® 100 Microbind® Affinity Blood Filter and its fields of application]

BACKGROUND

In 2019 the World Health Organization (WHO) listed antimicrobial resistance among the top 10 threats to global health. The Seraph® 100 Microbind® Affinity blood filter (Seraph® 100) has been in use since 2019 to eliminate pathogens from the bloodstream in addition to anti-infective pharmacotherapy. It is the first device used to rapidly and efficiently reduce the number of circulating bacteria and viruses.

OBJECTIVE

After a background on the concept of extracorporeal pathogen removal in general, this review summarizes the preclinical and clinical data on the Seraph® 100 Affinity Blood Filter. The clinical effect of this treatment and potential therapeutic options are described.

METHODS

Structured PubMed review including references published up to February 2024.

RESULTS

Case reports, uncontrolled observational studies and data from registries show widespread clinical use of the Seraph® 100 ranging from difficult to treat bacterial (super) infections to viral infections. The treatment can be done as stand-alone hemoperfusion or in combination with all forms of kidney replacement therapy as well as in extracorporeal membrane oxygenation.

CONCLUSION

The use of the Seraph® 100 varies in terms of duration, concomitant therapy and clinical settings. Due to the absence of prospective controlled trials the clinical effect cannot be properly evaluated.

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.

Enterobacter cloacae septicemia in a triple-cannula extracorporeal membrane oxygenation circulatory support treated with Seraph-100 Microbind affinity blood filter

Bloodstream infections (BSI) are frequently encountered during extracorporeal membrane oxygenation (ECMO) support. Once septicemia is observed, treatment should be rapid, adequate, and multifaceted, particularly in advanced ECMO configurations. We report on a case of a 60-year-old male patient with acute-on-chronic heart failure due to ischemic cardiomyopathy. The treatment was complicated by cardiogenic shock requiring veno-arterial ECMO support, and, due to persistent pulmonary congestion, an upgrade with an additional left-atrial drainage cannula. After seven days of ECMO support, septicemia with shock ensued. Ex iuvantibus antibiotic treatment was started promptly. We wanted to minimize the likelihood of bacterial biofilm build-up requiring an exchange of the ECMO circuit and cannula, which was expected to be challenging. Therefore, we added a Seraph-100 Microbind affinity blood filter (providing blood purification with the potential for rapid bacterial clearance) to the ECMO circuit. Initial blood cultures tested positive for Enterobacter cloacae. Following a course of Seraph-100 treatment, bacteremia, septicemia, and shock resolved. There was no need for a circuit or cannula exchange. The additional eleven days of ECMO support were uneventful. The patient was successfully bridged to long-term mechanical circulatory support. We believe that the synergistic effect of early implementation of both broad-spectrum antibiotic treatment and blood purification with the potential for rapid bacterial clearance (such as the one provided with the Seraph-100 Microbind affinity blood filter) is crucial in BSI in patients receiving advanced ECMO.

Sequential Extracorporeal Blood Purification Is Associated with Prolonged Survival among ICU Patients with COVID-19 and Confirmed Bacterial Superinfection

INTRODUCTION

This study investigates the impact of sequential extracorporeal treatments with oXiris® or CytoSorb® plus Seraph-100® on the clinical and laboratory parameters of critically ill COVID-19 patients with bacterial superinfection.

METHODS

Patients admitted to the intensive care unit with COVID-19, bacterial superinfection, and undergoing blood purification (BP) were enrolled in this prospective, single-center, observational study. "standard BP" with oXiris® or CytoSorb® were used in 35 COVID-19 patients with bacterial infection. Seraph-100® was added in 33 patients when available serially in the same oXiris® circuit or as sequential treatment with CytoSorb® as a sequential BP.

RESULTS

A significant reduction in SOFA score 3 days after treatment was observed in patients undergoing sequential BP (11.3 vs. 8.17, p < 0.01) compared to those undergoing "standard BP" (11.0 vs. 10.3, p > 0.05). The difference between the observed and expected mortality rate based on APACHE IV was greater in the sequential BP group (42.4% vs. 81.7%, p < 0.001) than the "standard BP" (74.2% vs. 81.7%, p > 0.05). Patients treated with sequential BP had a longer survival than those treated with "standard BP" (22.4 vs. 18.7 months; p < 0.001).

CONCLUSIONS

The sequential approach may enhance the positive effect of BP on organ dysfunction among critically ill patients with COVID-19 and bacterial superinfection.

Membrane-camouflaged biomimetic nanoparticles as potential immunomodulatory solutions for sepsis: An overview

Sepsis is a life-threatening organ dysfunction due to dysregulated host responses induced by infection. The presence of immune disturbance is key to the onset and development of sepsis but has remarkably limited therapeutic options. Advances in biomedical nanotechnology have provided innovative approaches to rebalancing the host immunity. In particular, the technique of membrane-coating has demonstrated remarkable improvements to therapeutic nanoparticles (NPs) in terms of tolerance and stability while also improving their biomimetic performance for immunomodulatory purposes. This development has led to the emergence of using cell-membrane-based biomimetic NPs in treating sepsis-associated immunologic derangements. In this minireview, we present an overview of the recent advances in membrane-camouflaged biomimetic NPs, highlighting their multifaceted immunomodulatory effects in sepsis such as anti-infection, vaccination, inflammation control, reversing of immunosuppression, and targeted delivery of immunomodulatory agents.

[Hemoperfusion and plasmapheresis in the intensive care unit]

In addition to kidney replacement procedures, several other extracorporeal procedures are employed in the intensive care unit. Hemoperfusion with activated charcoal was the predominant treatment used for removal of toxins from the 1970s until the millennium. Nowadays, this treatment does no longer play a clinically meaningful role as even strongly protein-bound toxins can be removed by effective dialysis procedures in case poisoning. The concept of a cytokine adsorber was introduced 10 years ago, which is directed towards withstanding the cytokine storm. Despite negative data from prospective randomized controlled studies, its use is steadily increasing in Germany. A totally different treatment concept is the biomimetic pathogen adsorber, which removes bacteria, viruses and fungi from the bloodstream by binding to immobilized heparin. Whether this rapid reduction of the pathogen load translates into an improvement of clinically relevant endpoints is unclear, as prospective randomized controlled studies are lacking. For the early hours of septic shock a very old procedure, plasmapheresis, has recently regained interest. The results of two large randomized controlled studies in this setting from Europe and Canada will become available in 2025/2026. The rationale to use plasma exchange in early sepsis is that this procedure not only removes cytokines but also replenishes reduced levels of protective factors, such as angiopoietin‑1, a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13 (ADAMTS-13) and protein C, if fresh plasma is used as exchange fluid. All afore mentioned procedures do not only have a different mode of action but are also used at seperate time points of bloodstream infections and/or sepsis.

Heparin, Heparan Sulphate and Sepsis: Potential New Options for Treatment

Sepsis is a life-threatening hyperreaction to infection in which excessive inflammatory and immune responses cause damage to host tissues and organs. The glycosaminoglycan heparan sulphate (HS) is a major component of the cell surface glycocalyx. Cell surface HS modulates several of the mechanisms involved in sepsis such as pathogen interactions with the host cell and neutrophil recruitment and is a target for the pro-inflammatory enzyme heparanase. Heparin, a close structural relative of HS, is used in medicine as a powerful anticoagulant and antithrombotic. Many studies have shown that heparin can influence the course of sepsis-related processes as a result of its structural similarity to HS, including its strong negative charge. The anticoagulant activity of heparin, however, limits its potential in treatment of inflammatory conditions by introducing the risk of bleeding and other adverse side-effects. As the anticoagulant potency of heparin is largely determined by a single well-defined structural feature, it has been possible to develop heparin derivatives and mimetic compounds with reduced anticoagulant activity. Such heparin mimetics may have potential for use as therapeutic agents in the context of sepsis.

Rationale for sequential extracorporeal therapy (SET) in sepsis

Sepsis and septic shock remain drivers for morbidity and mortality in critical illness. The clinical picture of patients presenting with these syndromes evolves rapidly and may be characterised by: (a) microbial host invasion, (b) establishment of an infection focus, (c) opsonisation of bacterial products (e.g. lipopolysaccharide), (d) recognition of pathogens resulting in an immune response, (e) cellular and humoral effects of circulating pathogen and pathogen products, (f) immunodysregulation and endocrine effects of cytokines, (g) endothelial and organ damage, and (h) organ crosstalk and multiple organ dysfunction. Each step may be a potential target for a specific therapeutic approach. At various stages, extracorporeal therapies may target circulating molecules for removal. In sequence, we could consider: (a) pathogen removal from the circulation with affinity binders and cartridges (specific), (b) circulating endotoxin removal by haemoperfusion with polymyxin B adsorbers (specific), (c) cytokine removal by haemoperfusion with sorbent cartridges or adsorbing membranes (non-specific), (d) extracorporeal organ support with different techniques for respiratory and cardiac support (CO₂ removal or extracorporeal membrane oxygenation), and renal support (haemofiltration, haemodialysis, or ultrafiltration). The sequence of events and the use of different techniques at different points for specific targets will likely require trials with endpoints other than mortality. Instead, the primary objectives should be to achieve the desired action by using extracorporeal therapy at a specific point.

Efficacy of hemoperfusion with Seraph-100 in series with single pass albumin dialysis in acute hepatitis B infection: A case report

Acute and acute-on-chronic liver failure is a cause of death in patients suffering from viral hepatitis, and many cases need liver transplantation. Infection from hepatitis B virus may range from asymptomatic to severe acute and fulminant hepatitis. In this setting, treatment is mainly supportive as there is no consensus on antiviral therapy based on non-nucleoside reverse transcriptase inhibitors. Single-pass albumin dialysis is a liver-support technique for patients suffering from liver failure, that has shown effectiveness in the removal of both water-soluble and albumin-bound toxins, which accumulate due to impairment of the liver's cleansing function. We report here the case of a 62-year-old male who presented with a severe acute hepatitis B infection, liver failure, and marked hyperbilirubinemia. Treatment with single-pass albumin dialysis combined with a hemoperfusion device was successful in improving clinical, physiological, and laboratory parameters.

Hemoperfusion with Seraph 100 Microbind Affinity Blood Filter Unlikely to Require Increased Antibiotic Dosing: A Simulations Study Using a Pharmacokinetic/Pharmacodynamic Approach

INTRODUCTION

The Seraph® 100 Microbind® Affinity Blood Filter (Seraph 100) is a hemoperfusion device that can remove pathogens from central circulation. However, the effect of Seraph 100 on achieving pharmacodynamic (PD) targets is not well described. We sought to determine the impact of Seraph 100 on ability to achieve PD targets for commonly used antibiotics.

METHODS

Estimates of Seraph 100 antibiotic clearance were obtained via literature. For vancomycin and gentamicin, published pharmacokinetic models were used to explore the effect of Seraph 100 on ability to achieve probability of target attainment (PTA). For meropenem and imipenem, the reported effect of continuous kidney replacement therapy (CKRT) on achieving PTA was used to extrapolate decisions for Seraph 100.

RESULTS

Seraph 100 antibiotic clearance is likely less than 0.5 L/h for most antibiotics. Theoretical Seraph 100 clearance up to 0.5 L/h and 2 L/h had a negligible effect on vancomycin PTA in virtual patients with creatinine clearance (CrCl) = 14 mL/min and CrCl >14 mL/min, respectively. Theoretical Seraph 100 clearance up to 0.5 L/h and 2 L/h had a negligible effect on gentamicin PTA in virtual patients with CrCl = 120 mL/min and CrCl <60 mL/min, respectively. CKRT intensity resulting in antibiotic clearance up to 2 L/h generally does not require dose increases for meropenem or imipenem. As Seraph 100 is prescribed intermittently and likely contributes far less to antibiotic clearance, dose increases would also not be required.

CONCLUSION

Seraph 100 clearance of vancomycin, gentamicin, meropenem, and imipenem is likely clinically insignificant. There is insufficient evidence to recommend increased doses. For aminoglycosides, we recommend extended interval dosing and initiating Seraph 100 at least 30 min to 1 h after completion of infusion to avoid the possibility of interference with maximum concentrations.

Staphylococcus aureus binding to Seraph® 100 Microbind® Affinity Filter: Effects of surface protein expression and treatment duration

INTRODUCTION

Extracorporeal blood purification systems represent a promising alternative for treatment of blood stream infections with multiresistant bacteria.

OBJECTIVES

The aim of this study was to analyse the binding activity of S. aureus to Seraph affinity filters based on heparin coated beads and to identify effectors influencing this binding activity.

RESULTS

To test the binding activity, we used gfp-expressing S. aureus Newman strains inoculated either in 0.9% NaCl or in blood plasma and determined the number of unbound bacteria by FACS analyses after passing through Seraph affinity filters. The binding activity of S. aureus was clearly impaired in human plasma: while a percent removal of 42% was observed in 0.9% NaCl (p-value 0.0472) using Seraph mini columns, a percent removal of only 10% was achieved in human plasma (p-value 0.0934). The different composition of surface proteins in S. aureus caused by the loss of SarA, SigB, Lgt, and SaeS had no significant influence on its binding activity. In a clinically relevant approach using the Seraph® 100 Microbind® Affinity Filter and 1000 ml of human blood plasma from four different donors, the duration of treatment was shown to have a critical effect on the rate of bacterial reduction. Within the first four hours, the number of bacteria decreased continuously and the reduction in bacteria reached statistical significance after two hours of treatment (percentage reduction 64%, p-value 0.01165). The final reduction after four hours of treatment was close to 90% and is dependent on donor. The capacity of Seraph® 100 for S. aureus in human plasma was approximately 5 x 108 cells.

CONCLUSIONS

The Seraph affinity filter, based on heparin-coated beads, is a highly efficient method for reducing S. aureus in human blood plasma, with efficiency dependent on blood plasma composition and treatment duration.

Hämoperfusion und Plasmapherese auf der Intensivstation

Neben Nierenersatzverfahren werden auf der Intensivstation mehrere andere extrakorporale Verfahren eingesetzt. In den 1970er- bis 2000er-Jahren stand die Hämoperfusion mit Aktivkohlekapseln zur Entfernung von Toxinen im Vordergrund. Dies ist mittlerweile aufgrund der effektiven Dialyseverfahren, die im Vergiftungsfall auch stark proteingebundene Toxine entfernen, fast bedeutungslos geworden. Vor 10 Jahren erlebte ein Zytokinadsorber die Markteinführung, der darauf gerichtet ist, den „Zytokinsturm“ zu überstehen. Dieser erfreut sich trotz ernüchternder Daten aus prospektiven, randomisierten, kontrollierten Studien wachsender Beliebtheit. Ein gänzlich anderes Therapiekonzept ist der biomimetische Pathogenadsorber, der Bakterien, Viren und Pilze durch Bindung an immobilisiertes Heparin aus dem Blutstrom entfernt. Ob sich diese schnelle Reduktion der Pathogenlast in eine Verbesserung klinisch relevanter Endpunkte übersetzt, ist unklar, da hier prospektive, randomisierte und kontrollierte Studien gänzlich fehlen. Für ein sehr altes Verfahren, nämlich die Plasmapherese, werden wir für die Frühphase der Sepsis bis zum Jahr 2025/2026 Ergebnisse aus 2 großen randomisierten, kontrollierten Studien aus Europa und Kanada erhalten. Neben der Entfernung von Zytokinen erhofft man sich durch die Verwendung von Frischplasma als Austauschflüssigkeit auch das Wiederauffüllen reduzierter protektiver Faktoren wie Angiopoietin 1, ADAMTS13 („a disintegrin and metalloproteinase with a thrombospondin type 1 motif, member 13“) und Protein C. Alle genannten Verfahren funktionieren nicht nur unterschiedlich, sondern werden auch zu unterschiedlichen Zeitpunkten der Blutstrominfektion/Sepsis eingesetzt.

Safety and efficacy of the Seraph® 100 Microbind® Affinity Blood Filter to remove bacteria from the blood stream: results of the first in human study

Background

Bacterial burden as well as duration of bacteremia influence the outcome of patients with bloodstream infections. Promptly decreasing bacterial load in the blood by using extracorporeal devices in addition to anti-infective therapy has recently been explored. Preclinical studies with the Seraph® 100 Microbind® Affinity Blood Filter (Seraph® 100), which consists of heparin that is covalently bound to polymer beads, have demonstrated an effective binding of bacteria and viruses. Pathogens adhere to the heparin coated polymer beads in the adsorber as they would normally do to heparan sulfate on cell surfaces. Using this biomimetic principle, the Seraph® 100 could help to decrease bacterial burden in vivo.

Methods

This first in human, prospective, multicenter, non-randomized interventional study included patients with blood culture positive bloodstream infection and the need for kidney replacement therapy as an adjunctive treatment for bloodstream infections. We performed a single four-hour hemoperfusion treatment with the Seraph® 100 in conjunction with a dialysis procedure. Post procedure follow up was 14 days.

Results

Fifteen hemodialysis patients (3F/12 M, age 74.0 [68.0–78.5] years, dialysis vintage 28.0 [11.0–45.0] months) were enrolled. Seraph® 100 treatment started 66.4 [45.7–80.6] hours after the initial positive blood culture was drawn. During the treatment with the Seraph® 100 with a median blood flow of 285 [225–300] ml/min no device or treatment related adverse events were reported. Blood pressure and heart rate remained stable while peripheral oxygen saturation improved during the treatment from 98.0 [92.5–98.0] to 99.0 [98.0–99.5] %; p = 0.0184. Four patients still had positive blood culture at the start of Seraph® 100 treatment. In one patient blood cultures turned negative during treatment. The time to positivity (TTP) was increased between inflow and outflow blood cultures by 36 [− 7.2 to 96.3] minutes. However, overall TTP increase was not statistical significant.

Conclusions

Seraph® 100 treatment was well tolerated. Adding Seraph® 100 to antibiotics early in the course of bacteremia might result in a faster resolution of bloodstream infections, which has to be evaluated in further studies.

Trail registration: ClinicalTrials.gov Identifier: NCT02914132, first posted September 26, 2016.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13054-022-04044-7.

Activated Platelets and Platelet-Derived Extracellular Vesicles Mediate COVID-19-Associated Immunothrombosis

Activated platelets and platelet-derived extracellular vesicles (EVs) have emerged as central players in thromboembolic complications associated with severe coronavirus disease 2019 (COVID-19). Platelets bridge hemostatic, inflammatory, and immune responses by their ability to sense pathogens via various pattern recognition receptors, and they respond to infection through a diverse repertoire of mechanisms. Dysregulated platelet activation, however, can lead to immunothrombosis, a simultaneous overactivation of blood coagulation and the innate immune response. Mediators released by activated platelets in response to infection, such as antimicrobial peptides, high mobility group box 1 protein, platelet factor 4 (PF4), and PF4⁺ extracellular vesicles promote neutrophil activation, resulting in the release of neutrophil extracellular traps and histones. Many of the factors released during platelet and neutrophil activation are positively charged and interact with endogenous heparan sulfate or exogenously administered heparin via electrostatic interactions or via specific binding sites. Here, we review the current state of knowledge regarding the involvement of platelets and platelet-derived EVs in the pathogenesis of immunothrombosis, and we discuss the potential of extracorporeal therapies using adsorbents functionalized with heparin to deplete platelet-derived and neutrophil-derived mediators of immunothrombosis.

Heparin-Functionalized Adsorbents Eliminate Central Effectors of Immunothrombosis, including Platelet Factor 4, High-Mobility Group Box 1 Protein and Histones

Inflammation and thrombosis are closely intertwined in numerous disorders, including ischemic events and sepsis, as well as coronavirus disease 2019 (COVID-19). Thrombotic complications are markers of disease severity in both sepsis and COVID-19 and are associated with multiorgan failure and increased mortality. Immunothrombosis is driven by the complement/tissue factor/neutrophil axis, as well as by activated platelets, which can trigger the release of neutrophil extracellular traps (NETs) and release further effectors of immunothrombosis, including platelet factor 4 (PF4/CXCL4) and high-mobility box 1 protein (HMGB1). Many of the central effectors of deregulated immunothrombosis, including activated platelets and platelet-derived extracellular vesicles (pEVs) expressing PF4, soluble PF4, HMGB1, histones, as well as histone-decorated NETs, are positively charged and thus bind to heparin. Here, we provide evidence that adsorbents functionalized with endpoint-attached heparin efficiently deplete activated platelets, pEVs, PF4, HMGB1 and histones/nucleosomes. We propose that this elimination of central effectors of immunothrombosis, rather than direct binding of pathogens, could be of clinical relevance for mitigating thrombotic complications in sepsis or COVID-19 using heparin-functionalized adsorbents.

Interim-analysis of the COSA (COVID-19 patients treated with the Seraph® 100 Microbind® Affinity filter) registry

Background

The Seraph^® 100 Microbind^® Affinity Blood Filter is a haemoperfusion device that is licensed for the reduction of pathogens, including several viruses, in the blood. It received Emergency Use Authorization for the treatment of severe coronavirus disease 2019 (COVID-19) by the Food and Drug Administration (FDA). Several studies have shown that the blood viral load of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) correlates with adverse outcomes and removal of the nucleocapsid of the SARS-CoV-2 virus by the Seraph^® 100 has been recently demonstrated. The aim of this registry was to evaluate the safety and efficacy of Seraph^® 100 treatment for COVID-19 patients.

Methods

Twelve hospitals from six countries representing two continents documented patient and treatment characteristics as well as outcome parameters without reimbursement. Additionally, mortality and safety results of the device were reported. A total of 102 treatment sessions in 82 patients were documented in the registry. Four patients were excluded from mortality analysis due to incomplete outcome data, which were available in the other 78 patients.

Results

Overall, a 30-day mortality rate of 46.2% in the 78 patients with complete follow-up was reported. The median treatment time was 5.00 h (4.00–13.42) and 43.1% of the treatments were performed as haemoperfusion only. Adverse events of the Seraph^® 100 treatment were reported in 8.8% of the 102 treatments and represented the premature end of treatment due to circuit failure. Patients who died were treated later in their intensive care unit (ICU) stay and onset of COVID symptoms. They also had higher ferritin levels. Multivariate Cox regression revealed that delayed Seraph^® 100 treatment after ICU admission (>60 h), as well as bacterial superinfection, were associated with mortality. While average predicted mortality rate according to Sequential Organ Failure Assessment (SOFA) score in ICU patients was 56.7%, the observed mortality was 50.7%. In non-ICU patients, Coronavirus Clinical Characterisation Consortium (4C) score average predicted a mortality rate of 38.0%, while the observed mortality rate was 11.1%.

Conclusions

The treatment of COVID-19 patients with Seraph^® 100 is well tolerated and the circuit failure rate was lower than previously reported for kidney replacement therapy (KRT) in COVID-19 patients. Mortality correlated with late initiation of Seraph treatment after ICU admission and bacterial superinfection. Compared with predicted mortality according to 4C and SOFA scores, mortality of Seraph^® 100-treated patients reported in the registry was lower.

Continuous renal replacement therapy under special conditions like sepsis, burn, cardiac failure, neurotrauma, and liver failure

Continuous renal replacement therapy (CRRT) in sepsis does have a role in removing excessive fluid, and also role in removal of mediators although not proven today, and to allow fluid space in order to feed. In these conditions, continuous renal replacement therapy can improve morbidity but never mortality so far. Regarding sepsis, timing has become a more important issue after decades and is currently more discussed than dosing. Rationale of blood purification has evolved a lot in the last years regarding sepsis with the discovery of many types of sorbent allowing ideas from science fiction to become reality in 2021. Undoubtedly, COVID-19 has reactivated the interest of blood purification in sepsis but also in COVID-19. Burn is even more dependent about removal of excessive fluid as compared to sepsis. Regarding cardiac failure, ultrafiltration can improve the quality of life and morbidity when diuretics are becoming inefficient but can never improve mortality. Regarding brain injury, CRRTs have several advantages as compared to intermittent hemodialysis. In liver failure, there have been no randomized controlled trials to examine whether single-pass albumin dialysis offers advantages over standard supportive care, and there is always the cost of albumin.

Seraph-100 Hemoperfusion in SARS-CoV-2-Infected Patients Early in Critical Illness: A Case Series

There is an urgent need for therapeutic interventions to alter the course of critically ill coronavirus disease 2019 (CO­VID-19) patients. We report our experience with the Seraph-100 Microbind Affinity Blood Filter (Seraph-100) in 4 patients with COVID-19 early in the course of their critical respiratory illnesses. Patients were diagnosed with COVID-19 and were admitted to intensive care with worsening respiratory failure but did not require dialysis or vasopressors. Patients had to have a PaO₂ to FiO₂ (P/F ratio) <150 to qualify for hemoperfusion therapy. All patients received standard medical therapy including oral vitamins C and D and zinc in addition to intravenous dexamethasone and remdesivir. Patients received a single 5- to 7-h session with Seraph-100 on a conventional dialysis machine (Fresenius 2008T) via a nontunneled central venous dialysis catheter with a goal of processing at least 100 L of blood. Patients received weight-based subcutaneous enoxaparin anticoagulation, as well as systemic intravenous heparin (70 units/kg), just prior to hemofiltration. Treatment with Seraph-100 hemoperfusion was well tolerated, and all patients were able to finish their prescribed therapy. All patients treated with Seraph-100 survived to be discharged from the hospital. Well-designed clinical trials are needed to determine the overall safety and efficacy of the Seraph-100 Microbind Affinity Blood Filter in COVID-19 patients.

Heparin-based blood purification attenuates organ injury in baboons with Streptococcus pneumoniae pneumonia

Bacterial pneumonia is a major cause of morbidity and mortality worldwide despite the use of antibiotics, and novel therapies are urgently needed. Building on previous work, we aimed to 1) develop a baboon model of severe pneumococcal pneumonia and sepsis with organ dysfunction and 2) test the safety and efficacy of a novel extracorporeal blood filter to remove proinflammatory molecules and improve organ function. After a dose-finding pilot study, 12 animals were inoculated with Streptococcus pneumoniae [5 × 10⁹ colony-forming units (CFU)], given ceftriaxone at 24 h after inoculation, and randomized to extracorporeal blood purification using a filter coated with surface-immobilized heparin sulfate (n = 6) or sham treatment (n = 6) for 4 h at 30 h after inoculation. For safety analysis, four uninfected animals also underwent purification. At 48 h, necropsy was performed. Inoculated animals developed severe pneumonia and septic shock. Compared with sham-treated animals, septic animals treated with purification displayed significantly less kidney injury, metabolic acidosis, hypoglycemia, and shock (P < 0.05). Purification blocked the rise in peripheral blood S. pneumoniae DNA, attenuated bronchoalveolar lavage (BAL) CCL4, CCL2, and IL-18 levels, and reduced renal oxidative injury and classical NLRP3 inflammasome activation. Purification was safe in both uninfected and infected animals and produced no adverse effects. We demonstrate that heparin-based blood purification significantly attenuates levels of circulating S. pneumoniae DNA and BAL cytokines and is renal protective in baboons with severe pneumococcal pneumonia and septic shock. Purification was associated with less severe acute kidney injury, metabolic derangements, and shock. These results support future clinical studies in critically ill septic patients.

Treatment of a Critically Ill COVID-19 Patient with the Seraph 100 Microbind Affinity Filter

The coronavirus disease 2019 (COVID-19) pandemic has a serious impact on health and economics worldwide. Even though the majority of patients present with moderate and mild symptoms, yet a considerable portion of patients need to be treated in the intensive care unit. Aside from dexamethasone, there is no established pharmacological therapy. Moreover, some of the currently tested drugs are contraindicated for special patient populations like remdesivir for patients with severely impaired renal function. On this background, several extracorporeal treatments are currently explored concerning their potential to improve the clinical course and outcome of critically ill patients with COVID-19. Here, we report the use of the Seraph 100 Microbind Affinity filter, which is licensed in the European Union for the removal of pathogens. Authorization for emergency use in patients with COVID-19 admitted to the intensive care unit with confirmed or imminent respiratory failure was granted by the U.S. Food and Drug Administration on April 17, 2020.

A 53-year-old Caucasian male with a severe COVID-19 infection was treated with a Seraph Microbind Affinity filter hemoperfusion after clinical deterioration and commencement of mechanical ventilation. The 70-minute treatment at a blood flow of 200 mL/minute was well tolerated, and the patient was hemodynamically stable. The hemoperfusion reduced D-dimers dramatically.

This case report suggests that the use of Seraph 100 Microbind Affinity filter hemoperfusion might have positive effects on the clinical course of critically ill patients with COVID-19. However, future prospective collection of data ideally in randomized trials will have to confirm whether the use of Seraph 100 Microbind Affinity filter hemoperfusion is an option of the treatment for COVID-19.