Coupled plasma haemofiltration filtration in severe sepsis: systematic review and meta-analysis

The Techniques of Blood Purification in the Treatment of Sepsis and Other Hyperinflammatory Conditions

Even in the absence of strong indications deriving from clinical studies, the removal of mediators is increasingly used in septic shock and in other clinical conditions characterized by a hyperinflammatory response. Despite the different underlying mechanisms of action, they are collectively indicated as blood purification techniques. Their main categories include blood- and plasma processing procedures, which can run in a stand-alone mode or, more commonly, in association with a renal replacement treatment. The different techniques and principles of function, the clinical evidence derived from multiple clinical investigations, and the possible side effects are reviewed and discussed along with the persisting uncertainties about their precise role in the therapeutic armamentarium of these syndromes.

Renal replacement therapy for acute kidney injury in burn patients, an international survey and a qualitative review of current controversies

BACKGROUND OF THE STUDY

Acute kidney injury (AKI) is a common complication in critically ill burn patients and is associated with a number of serious adverse outcomes. The clinical decision-making process related to the management of AKI in burn patients is complex and has not been sufficiently standardized. The main aim of this study was to explore the diagnostic approach and clinician's attitudes toward the management of AKI and RRT in burn patients around the world.

METHODS

The questionnaire was widely distributed among the members of International Society for Burn Injury (ISBI), who were invited to complete the survey. Data collection and report was compliant with the the Checklist for Reporting Results of Internet E-Surveys (CHERRIES) Web-survey guidelines. The survey form with multiple-choice questions was divided into 3 parts: a. physician and institutional demographics, b. AKI diagnostic information, c. technical aspects of RRT.

RESULTS

A total of 44 respondents worldwide submitted valuable data in the 2-month period. Of all respondents, 43.2% were from Europe, 30% from North America, 7% from South-East Asia 2.3% from Africa and 18.2% from other regions. 93.1% of participants declare that they use specific definitions to detect AKI, while 11.4% declare the use of renal ultrasonography for AKI diagnosis. CRRT appeared to be the most preferred option by 43.2% of participants, followed by intermittent hemodialysis (25%), and prolonged intermittent RRT (6.8%). The expertise to deliver a modality and the availability of resources were considered important factors when selecting the optimal RRT modality by 20.5% and 29.6% of respondents. The use of specific serum biomarkers for AKI diagnosis are stated by 16% of respondents; 25% of specialists refer to the use of biomarkers of AKI as a criterium for discontinuing the RRT. Femoral vena and right jugular vena were the most frequently used location for RRT temporary catheter placement, 54.6% of respondents declared using ultrasound guidance for catheter placement.

CONCLUSIONS

The majority of burn specialists use specific consensus classifications to detect acute kidney injury. Continuous renal replacement therapy appeared to be the most preferred option, while the expertise to deliver a particular modality and resources availability play a significant role in modality selection. The use of ultrasound and specific biomarkers for AKI evaluation is infrequent in routine clinical practice.

Application of Adsorptive Blood Purification Techniques during Cardiopulmonary Bypass in Cardiac Surgery

By reason of surgical demand, the majority of cardiovascular procedures still depend on the use of cardiopulmonary bypass (CPB). Due to the nonphysiological state of CPB, it can cause complex and unpredictable inflammatory response, which may lead to significant morbidity and mortality. Unfortunately, the pharmacological and mechanical strategies that currently exist do not offer significant advantages in controlling inflammatory response and improving patient outcomes. The best strategy to reduce inflammation in CPB is still uncertain. In recent years, adsorptive blood purification techniques (BPTs) have emerged, among which CytoSorb is the latest representative device. Currently, the primary application area of adsorptive BPTs is in the control and treatment of systemic hyperinflammatory states, such as refractory septic shock patients. However, the evidences on efficacy and safety of adsorptive BPTs application during CPB surgery are still inconclusive, so we summarize the relevant evidences here and suggest future potential research areas.

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

Aim: New coronavirus disease (COVID-19) has become an international emergency. As many of the intensive care unit (ICU) patients with the disease also present multiple organ failure, blood purification techniques might be a good choice in their treatment. In this study we aimed to investigate the role of cytokine removal in COVID-19 patients managed in ICUs. Methods: For this case-control study we have investigated the role of the cytokine removal by means of two resin membranes (HA330 and Mediasorb) in COVID-19 patients managed in ICUs. Particularly, we investigated the overtime variation in clinical severity scores, laboratory variables, and effects on hospital and ICU stay and mortality. Results: Seventy-two patients have been evaluated, of which half constituted Cytokine Filtration (CF) Group, and other half the Case-Control (CC) Group. Mortality was 55.6% and 50% in CF and CC groups, respectively. In the CF Group, there was decrease in C-reactive protein (CRP) and fibrinogen levels measured at the end of cytokine adsorption; lymphocyte count and ratio were increased, whereas neutrophile ratio was decreased. There were no differences between the groups regarding other laboratory variables, SOFA scores and vasopressor uses. Conclusions: We have demonstrated decrease in CRP, fibrinogen and increase in lymphocyte count in the patients having cytokine adsorption, but there was no clinical reflection of these benefits, and no decrease in mortality as well. Even though there is physio-pathologic rationale to use cytokine adsorption techniques for immunomodulation in critically ill COVID-19 patients, it is early to make strong suggestions about their benefits.

Signaling pathways and intervention therapies in sepsis

Sepsis is defined as life-threatening organ dysfunction caused by dysregulated host systemic inflammatory and immune response to infection. Over decades, advanced understanding of host-microorganism interaction has gradually unmasked the genuine nature of sepsis, guiding toward new definition and novel therapeutic approaches. Diverse clinical manifestations and outcomes among infectious patients have suggested the heterogeneity of immunopathology, while systemic inflammatory responses and deteriorating organ function observed in critically ill patients imply the extensively hyperactivated cascades by the host defense system. From focusing on microorganism pathogenicity, research interests have turned toward the molecular basis of host responses. Though progress has been made regarding recognition and management of clinical sepsis, incidence and mortality rate remain high. Furthermore, clinical trials of therapeutics have failed to obtain promising results. As far as we know, there was no systematic review addressing sepsis-related molecular signaling pathways and intervention therapy in literature. Increasing studies have succeeded to confirm novel functions of involved signaling pathways and comment on efficacy of intervention therapies amid sepsis. However, few of these studies attempt to elucidate the underlining mechanism in progression of sepsis, while other failed to integrate preliminary findings and describe in a broader view. This review focuses on the important signaling pathways, potential molecular mechanism, and pathway-associated therapy in sepsis. Host-derived molecules interacting with activated cells possess pivotal role for sepsis pathogenesis by dynamic regulation of signaling pathways. Cross-talk and functions of these molecules are also discussed in detail. Lastly, potential novel therapeutic strategies precisely targeting on signaling pathways and molecules are mentioned.

Effects of Medium Cutoff Membranes on Pro-Inflammatory Cytokine and Oxidative Marker Levels in Patients with Sepsis Who Developed Acute Kidney Injury

INTRODUCTION

There is insufficient data on the role of the medium cutoff (MCO) membranes in the clearance of pro-inflammatory cytokines and oxidant radicals in patients with sepsis requiring hemodialysis.

METHODS

The study consisted of 38 septic patients who developed acute kidney injury (AKI) and who were scheduled to undergo 2 sessions of hemodialysis. Nineteen patients underwent their first dialysis session with the MCO membrane and 19 patients with the high-flux (HF) membrane. In the second session, the membranes were switched. Pro-inflammatory cytokine and oxidative marker levels were measured in blood samples obtained before and after both dialysis sessions. Reduction ratios were compared for the 2 types of hemodialysis membranes.

RESULTS

After the first session, there was a greater reduction in tumor necrosis factor (TNF)-α with the MCO membrane (28.2 ± 21.1 vs. 8.0 ± 6.6, p = 0.001). After the second session, there was a greater reduction in interleukin (IL)-6 (27.8 ± 26.5 vs. 5.9 ± 13.3, p = 0.003) and IL-1β (20.5 ± 21.1 vs. 4.0 ± 6.5, p = 0.004) with the MCO membrane. When the first and second sessions of all 38 patients were compared, the reductions in TNF-α, IL-6, and IL-1β were consistently greater for MCO than HF (p = 0.001, p = 0.006, p < 0.001, respectively). The reductions in total antioxidant status, total oxidant status, and myeloperoxidase were not statistically different for the 2 types of dialysis membranes.

CONCLUSIONS

MCO membrane was superior to HF membrane in the removal of cytokines in septic patients with AKI. However, a similar effect was not observed for oxidative stress markers.

Renal Replacement Techniques in Septic Shock

Sepsis is defined as a life-threatening organ dysfunction caused by a dysregulated host response to an infection; it carries a risk for mortality, considerably exceeding that of a mere infection. Sepsis is the leading cause for acute kidney injury (AKI) and the requirement for renal replacement therapy (RRT) in intensive care unit (ICU) patients. Almost every second critically ill patient with sepsis will develop AKI. In septic shock, the dysregulated host response to infectious pathogens leads to a cytokine storm with uncontrolled production and release of humoral proinflammatory mediators that evoke cellular toxicity and promote the development of organ dysfunction and increased mortality. In addition to treating AKI, RRT techniques can be employed for extracorporeal adsorption of inflammatory mediators using specifically developed adsorption membranes, hemoperfusion sorbent cartridges or columns; these techniques are intended to decrease the level and early deleterious effects of circulating proinflammatory cytokines and endotoxins during the first hours and days of septic shock treatment, in order to improve patient outcomes. Several methods and devices, such as high cut-off membranes, the Oxiris®-AN69 membrane, CytoSorb® and HA380 cytokine hemoadsorption, polymyxin B endotoxin adsorption, and plasmapheresis have been examined in small study series or are under evaluation as ways of improving patient outcomes in septic shock. However, to date, the data on actual outcome benefits have remained controversial, as discussed in this review.

Application of extracorporeal therapies in critically ill COVID-19 patients

The coronavirus disease 2019 (COVID-19) pandemic is a major public health event caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 has spread widely all over the world. A high proportion of patients become severely or critically ill, and suffer high mortality due to respiratory failure and multiple organ dysfunction. Therefore, providing timely and effective treatment for critically ill patients is essential to reduce overall mortality. Convalescent plasma therapy and pharmacological treatments, such as aerosol inhalation of interferon-α (IFN-α), corticosteroids, and tocilizumab, have all been applied in clinical practice; however, their effects remain controversial. Recent studies have shown that extracorporeal therapies might have a potential role in treating critically ill COVID-19 patients. In this review, we examine the application of continuous renal replacement therapy (CRRT), therapeutic plasma exchange (TPE), hemoadsorption (HA), extracorporeal membrane oxygenation (ECMO), and extracorporeal carbon dioxide removal (ECCO₂R) in critically ill COVID-19 patients to provide support for the further diagnosis and treatment of COVID-19.

An update on membranes and cartridges for extracorporeal blood purification in sepsis and septic shock

PURPOSE OF REVIEW

This review aims to summarize the most recent advances on different membranes and cartridges used for extracorporeal blood purification in critically ill patients with sepsis or septic shock.

RECENT FINDINGS

Despite positive signals from experimental, cases and small clinical studies, blood purification showed no distinct morbidity and mortality benefit in large clinical trials.

SUMMARY

None of the discussed specific membranes or cartridges can currently be recommended as sole adjunctive treatment in sepsis and septic shock. Any available technique should be timely initiated and adapted to the patient's status. Sickest patients seem to benefit more from blood purification. Patient selection is thus of crucial importance and may be optimized by focusing on disease severity and degree of organ failure. Measurement of endotoxin activity and plasma procalcitonin levels can support the selection process but ideal cutoff values need to be defined. Well-designed prospective randomized clinical trials assessing or comparing the various available membranes and cartridges are eagerly awaited.

Extracorporeal techniques for the treatment of critically ill patients with sepsis beyond conventional blood purification therapy: the promises and the pitfalls

Sepsis is one of the leading causes of morbidity and mortality worldwide. It is characterized by a dysregulated immune response to infections that results in life-threatening organ dysfunction and even death. Bacterial cell wall components (endotoxin or lipopolysaccharide), known as pathogen-associated molecular patterns (PAMPs), as well as damage-associated molecular patterns (DAMPs) released by host injured cells, are well-recognized triggers resulting in the elevation of both pro-inflammatory and anti-inflammatory cytokines. Understanding this complex pathophysiology has led to the development of therapeutic strategies aimed at restoring a balanced immune response by eliminating/deactivating these inflammatory mediators. Different extracorporeal techniques have been studied in recent years in the hope of maximizing the effect of renal replacement therapy in modulating the exaggerated host inflammatory response, including the use of high volume hemofiltration (HVHF), high cut-off (HCO) membranes, adsorption alone, and coupled plasma filtration adsorption (CPFA). These strategies are not widely utilized in practice, depending on resources and local expertise. The literature examining their use in septic patients is growing, but the evidence to support their use at this stage is considered of low level. Our aim is to provide a comprehensive overview of the technical aspects, clinical applications, and associated side effects of these techniques.