Cytokine Adsorption in Critically Ill COVID-19 Patients, a Case-Control Study

[Hemoperfusion in anesthesia and intensive care medicine: benefits, risks, and evidence for different systems]

BACKGROUND

Hemoperfusion is a technique for the extracorporeal elimination of endogenous and exogenous toxins and harmful mediators by adsorption. It can be used as a stand-alone device, as part of a heart-lung machine or extracorporeal membrane oxygenation (ECMO) or, as is currently the case, integrated into a kidney replacement procedure. In the meantime, various suppliers offer devices with different technologies.

OBJECTIVE

The aim of this work was to evaluate the benefits, risks and evidence of the different systems, how they work and for which indications they are approved in Germany.

METHOD

To achieve this goal, a narrative assessment of the existing literature and guidelines for different indications was performed. The focus was on in vivo studies.

RESULTS

In principle, a distinction must be made in adsorption techniques between pure adsorption and the combination as adsorption and kidney replacement therapy. The adsorbers available in Germany include Cytosorb®, HA-330, Seraph®-100 and Toraymyxin. Combined procedures (adsorption and kidney replacement) are offered with coupled plasma filtration and adsorption (CPFA) and oXiris®. Most adsorbers have been developed for cytokine and endotoxin removal in patients with sepsis; however, to date, no randomized controlled trial (RCT) has demonstrated a survival benefit when using hemoperfusion. Therefore, the S3 guidelines for treatment of sepsis and the surviving sepsis campaign guidelines advise against its routine use. When the corona pandemic began, hemoperfusion was considered as a promising therapeutic approach. Cytosorb®, Seraph®-100, and oXiris® received emergency approval by the FDA to be used in critically ill patients with COVID-19, so questions arose about the appropriateness and importance of its use; however, the data generated did not show positive results, so its use cannot be recommended routinely either. In addition, they are not mentioned as a treatment option in the current guidelines. The use of adsorption procedures in patients with liver failure and rhabdomyolysis has only been rudimentarily studied, so any evidence is currently lacking. The only adsorber that has CE approval in Germany for both applications is Cytosorb®. In the next few years, studies will have to follow that investigate the efficacy and thus either justify or refute the use in clinical routine. Hemoperfusion procedures are used in the heart-lung machine as part of cardiac surgery for either cytokine or anticoagulant adsorption. No congruent data are available to support the use for the elimination of cytokines. If emergency cardiac surgery is required in a patient with pre-existing anticoagulation, hemoperfusion procedures can be used to prevent bleeding complications. Cytosorb® has CE approval for this indication. All available techniques are nonselective adsorption processes, so that adsorption of known and unknown substances can occur. Unintentional adsorption of drugs, such as various anti-infective agents is a relevant risk, especially when used in patients with sepsis.

DISCUSSION

Various adsorption systems can eliminate different known and unknown substances. Currently, there is a lack of evidence for all indications and systems to justify their routine use except in clinical trials. Future clinical trials should evaluate the potential benefits but also dangers, so that in the meantime the routine use can be justified or a recommendation against the use can be given.

EFFICACY OF SUPPLEMENTAL HEMOADSORPTION THERAPY ON SEVERE AND CRITICAL PATIENTS WITH COVID-19: AN EVIDENCE-BASED ANALYSIS

ABSTRACT

Background: The COVID-19 pandemic has posed a disproportionately high threat to the global health system and social stability. COVID-19 damage can lead to hyperinflammation and tissue damage due to a "cytokine storm," which in turn contributes to an increase in the mortality rate. Extracorporeal hemoadsorption therapy (HAT) in patients with severe COVID-19 may improve organ function and stabilize hemodynamic status; however, the effects of supplemental HAT remain controversial. Methods: The Cochrane Library, Embase, and PubMed databases were comprehensively searched from inception to August 20, 2022, for potential studies. Results: A total of 648 patients with severe COVID-19 in three randomized controlled trials and 11 observational studies met the inclusion criteria. A meta-analysis indicated that supplemental HAT significantly improved the mortality rate of patients with severe COVID-19 compared with conventional therapy (relative risk [RR] = 0.74, 95% confidence interval [CI] = 0.56 to 0.96, P = 0.026). In subgroup analyses, supplemental HAT significantly decreased mortality rates in patients without extracorporeal membrane oxygenation (ECMO) support (RR = 0.59, 95% CI = 0.44-0.79, P < 0.0001), while a significant difference was not observed in patients requiring ECMO support (RR = 1.61, 95% CI = 0.63-4.09, P = 0.316). Standardized mean difference (SMD) meta-analysis showed that IL-6 removal was more significant in HAT group than conventional therapy group (SMD = 0.46, 95% CI = 0.01 to 0.91, P = 0.043), followed by C-reactive protein (SMD = 0.70, 95% CI = -0.04 to 1.44, P = 0.065) and IL-8 (SMD = 0.36, 95% CI = -0.34 to 1.07, P = 0.311). No evidence of substantial publication bias concerning mortality was observed. Conclusion: Given the better mortality outcomes, HAT confers clinical benefits to patients with severe COVID-19, which correlated with cytokine removal by HAT. Cytokine adsorption may not provide clinical benefits for patients with severe COVID-19 requiring ECMO and should be used with caution. However, because of the very low quality of evidence, multicenter randomized trials with large sample sizes are required to verify these findings.

Endothelial Glycocalyx Injury in SARS-CoV-2 Infection: Molecular Mechanisms and Potential Targeted Therapy

This review aims at summarizing state-of-the-art knowledge on glycocalyx and SARS-CoV-2. The endothelial glycocalyx is a dynamic grid overlying the surface of the endothelial cell (EC) lumen and consists of membrane-bound proteoglycans and glycoproteins. The role of glycocalyx has been determined in the regulation of EC permeability, adhesion, and coagulation. SARS-CoV-2 is an enveloped, single-stranded RNA virus belonging to β-coronavirus that causes the outbreak and the pandemic of COVID-19. Through the respiratory tract, SARS-CoV-2 enters blood circulation and interacts with ECs possessing angiotensin-converting enzyme 2 (ACE2). Intact glycolyx prevents SARS-CoV-2 invasion of ECs. When the glycocalyx is incomplete, virus spike protein of SARS-CoV-2 binds with ACE2 and enters ECs for replication. In addition, cytokine storm targets glycocalyx, leading to subsequent coagulation disorder. Therefore, it is intriguing to develop a novel treatment for SARS-CoV-2 infection through the maintenance of the integrity of glycocalyx. This review aims to summarize state-of-the-art knowledge of glycocalyx and its potential function in SARS-CoV-2 infection.

Effects of cytokine hemadsorption as salvage therapy on common laboratory parameters in patients with life-threatening COVID-19

BACKGROUND

The COVID-19 pandemic has led to emergency approval of treatment modalities unusual for viruses, such as therapeutic cytokine Hemadsorption(HA). This study aims to investigate the experience of salvage HA therapy and the effect of HA on routine laboratory tests.

METHODS

Life-threatening COVID-19 patients followed up between April 2020 and October 2022 who underwent HA salvage therapy were retrospectively enrolled. Data derived from the medical records were evaluated to meet the assumptions of statistical tests, and those that met the relevant statistical rules were selected for further analysis. Tests of Wilcoxon, Paired-T, and repeated measures-ANOVA were used to analyse the laboratory tests performed before and after HA among the surviving and nonsurviving patients. P < 0.05 was selected for the statistical significance of the alpha.

RESULTS

A total of 55 patients were enrolled in the study. Fibrinogen (p = 0.007), lactate dehydrogenase (LDH) (p = 0.021), C-reactive protein (CRP) (p < 0.0001), and platelet (PLT) (p = 0.046) levels showed a significant decrease with the HA effect. WBC (p = 0.209), lymphocyte (p = 0.135), procalcitonin (PCT) (p = 0.424), ferritin (p = 0.298), and D-dimer (p = 0.391) levels were not affected by HA. Ferritin level was significantly affected by survival status (p = 0.010). All patients tolerated HA well, and 16.4 % (n = 9) of the patients with life-threatening COVID-19 survived.

CONCLUSION

HA is well tolerated even when used as a last option. However, HA may not affect WBC, lymphocyte, and D-dimer levels. In contrast, the effect of HA could limit the benefits of LDH, CRP, and fibrinogen in various clinical assessments. This study suggests that HA treatment could be beneficial even if selected as a salvage therapy.

Effect of extracorporeal hemoadsorption in critically ill patients with COVID-19: A narrative review

COVID-19 has been affecting the world unprecedentedly and will remain widely prevalent due to its elusive pathophysiological mechanism and the continuous emergence of new variants. Critically ill patients with COVID-19 are commonly associated with cytokine storm, multiple organ dysfunction, and high mortality. To date, growing evidence has shown that extracorporeal hemoadsorption can exert its adjuvant effect to standard of care by regulating immune homeostasis, reducing viremia, and decreasing endotoxin activity in critically ill COVID-19 cases. However, the selection of various hemofilters, timing of initiation and termination of hemoadsorption therapy, anticoagulation management of extracorporeal circuits, identification of target subgroups, and ultimate survival benefit remain controversial. The purpose of this narrative review is to comprehensively summarize the rationale for the use of hemoadsorption in critically ill patients with COVID-19 and to gather the latest clinical evidence in this field.