Effect of Third and Fourth mRNA-Based Booster Vaccinations on SARS-CoV-2 Neutralizing Antibody Titer Formation, Risk Factors for Non-Response, and Outcome after SARS-CoV-2 Omicron Breakthrough Infections in Patients on Chronic Hemodialysis: A Prospective Multicenter Cohort Study

The aim of this study is to determine the effect of repeated vaccinations on neutralizing SARS-CoV-2 IgG antibody titers, evaluate risk factors for immunological non-response, and to report breakthrough infections in chronic hemodialysis patients. Methods: A prospective, multi-center cohort study in 163 chronic hemodialysis patients was conducted. Antibody titers were measured three months after second, third, and fourth (10 pts) booster vaccinations. SARS-CoV-2 neutralizing antibody titers in BAU/mL and % inhibition were divided into three categories (<216, 216–433, >433 and <33, 33–66, and >66%). Somers’s test, paired t-test, and univariable and multivariable logistic regression analysis were applied to evaluate differences in antibody levels and search for risk factors for vaccination failure defined as neutralizing titers <50% and/or need for repeated booster vaccinations. Furthermore, we report on a case series to describe characteristics of patients after four vaccinations (n = 10) and breakthrough infections (n = 20). Results: Third dose boosters resulted in higher proportions of patients with neutralizing antibody levels >66% as compared to after the second dose (64.7% after second dose vs. 88.9% after third dose, p = 0.003), as well as in a respective increase in neutralizing titer levels in % from 68 ± 33% to 89 ± 24 (p < 0.001). The proportion of patients with IgG-titers below 216 BAU/mL decreased from 38.6 to 10.5% (p ≤ 0.001). Age (p = 0.004, OR 1.066, 95% CI 1.020–1.114) and presence of immunosuppressive medications (p = 0.002, OR 8.267, 95% CI 2.206–30.975) were identified as major risk factors for vaccination failure. Repeated booster vaccinations ≥4 times were effective in 8 out of 10 former low-responders (80%) without any side effects or safety concerns. Breakthrough infections showed a clinically mild course but were associated with prolonged viral shedding on PCR-testing ranging 7–29 (mean 13) days. Conclusions: Third and fourth mRNA-based booster vaccinations resulted in higher and longer lasting SARS-CoV-2 antibody levels as compared to after two dosages. The presence of immunosuppressive medication and repeat vaccinations are major potentially modifiable measures to increase antibody levels in non-or low-responders. Breakthrough infections with SARS-CoV-2 Omicron were associated with prolonged viral shedding but clinically mild disease courses.

[Present practise patterns of renal replacement therapy in German intensive care medicine]

About 50% of all critically ill patients develop acute kidney injury (AKI) and approximately 15% receive renal replacement therapy (RRT). Although RRT is frequently used in intensive care units in Germany, it is currently unknown which RRT procedures are available, which qualification the involved staff has, which anticoagulation strategies are used and how RRT doses are prescribed. To investigate quality and structural characteristics of the performance of RRT in intensive care units throughout Germany, the German Interdisciplinary Society of Intensivists (Deutsche Interdisziplinäre Vereinigung für Intensiv- und Notfallmedizin [DIVI]) performed an inquiry among their members. A total of 897 members participated in the survey in which practical aspects were queried. In 69.1% of the cases, RRT was performed in hospitals with more than 400 beds and in 74.5% in university hospitals or other primary care hospitals. Furthermore, 93.3% of clinics are equipped with continuous and 75.8% with intermittent renal replacement devices. In 91.9%, indication for initiation of RRT was performed by trained physicians specialized in intensive care medicine or nephrologists. Intermittent as well as continuous modalities are both present in three-quarters of cases, which allows for individualized therapy. However, the documentation of dialysis dose needs to be improved.

Cyclosporine A-Induced Conchal Hyperplasia with Nasal Obstruction in a Patient with Membranous Nephropathy

Patient: Female, 66-year-old

Final Diagnosis: Cyclosporine induced hyperplasia of the tubinates

Symptoms: Dyspnea

Medication:—

Clinical Procedure: Drug withdrawal

Specialty: Dentistry • Nephrology • Otolaryngology

Angiogenic Role of Mesothelium-Derived Chemokine CXCL1 During Unfavorable Peritoneal Tissue Remodeling in Patients Receiving Peritoneal Dialysis as Renal Replacement Therapy

Peritoneal dialysis (PD) is a valuable ‘home treatment’ option, even more so during the ongoing Coronavirus pandemic. However, the long-term use of PD is limited by unfavourable tissue remodelling in the peritoneal membrane, which is associated with inflammation-induced angiogenesis. This appears to be driven primarily through vascular endothelial growth factor (VEGF), while the involvement of other angiogenic signaling pathways is still poorly understood. Here, we have identified the crucial contribution of mesothelial cell-derived angiogenic CXC chemokine ligand 1 (CXCL1) to peritoneal angiogenesis in PD. CXCL1 expression and peritoneal microvessel density were analysed in biopsies obtained by the International Peritoneal Biobank (NCT01893710 at www.clinicaltrials.gov), comparing 13 children with end-stage kidney disease before initiating PD to 43 children on chronic PD. The angiogenic potential of mesothelial cell-derived CXCL1 was assessed in vitro by measuring endothelial tube formation of human microvascular endothelial cells (HMECs) treated with conditioned medium from human peritoneal mesothelial cells (HPMCs) stimulated to release CXCL1 by treatment with either recombinant IL-17 or PD effluent. We found that the capillary density in the human peritoneum correlated with local CXCL1 expression. Both CXCL1 expression and microvessel density were higher in PD patients than in the age-matched patients prior to initiation of PD. Exposure of HMECs to recombinant CXCL1 or conditioned medium from IL-17-stimulated HPMCs resulted in increased endothelial tube formation, while selective inhibition of mesothelial CXCL1 production by specific antibodies or through silencing of relevant transcription factors abolished the proangiogenic effect of HPMC-conditioned medium. In conclusion, peritoneal mesothelium-derived CXCL1 promotes endothelial tube formation in vitro and associates with peritoneal microvessel density in uremic patients undergoing PD, thus providing novel targets for therapeutic intervention to prolong PD therapy.

A Rare Cause of Left Shoulder Pain in a Peritoneal Dialysis Patient

Patient: Male, 46-year-old

Final Diagnosis: Ectopic metastatic calcification

Symptoms: Left shoulder pain

Medication: —

Clinical Procedure: Decrease serum phosphate levels

Specialty: Nephrology • Orthopedics and Traumatology

Lactate based Scoring System in the diagnosis of necrotizing fasciitis

INTRODUCTION

Necrotizing fasciitis (NF) is a rare and quickly progressing infection and leads to 100% mortality if untreated. Quick diagnosis and an early and radical surgical treatment are essential for stopping bacterial progression. Unfortunately, the absence of clear clinical signs makes the diagnosis often challenging. Therefore, we searched for easy determinable predictive laboratory markers for NF. This is the first study which includes lactate values in a new score.

MATERIAL AND METHODS

A retrospective analysis of patients with NF (n = 44) and patients with erysipelas (n = 150) was performed. Lactate values, patients` demographics, clinical presentations, site of infection, comorbidities, microbiological and laboratory findings, antibiotic therapies and LRINEC and modified LRINEC Scores were analyzed. Logistic regression analysis was used to derive adjusted weights, and final simple point score was assessed with a ROC curve analysis.

RESULTS

Patients with NF had a mean age of 57 years, patients with erysipelas 65 years. The median hospital length of stay was 8 and 49 days in patients with erysipelas and NF, respectively. While only one patient (0.7 %) in the group of erysipelas died, the mortality rate of patients with NF was 9/44 (20.5 %). The lactate values were statistically significant higher in the NF group 4.1 vs. 2.0 mmol/l (p < 0.001). The new created CologNe-FaDe-Score shows the highest AUC-value with 0.907.

CONCLUSION

With the help of lactate values the CologNe-FaDe-Score consists of easily practicable and highly available parameters, which could sensitize diagnosis.

Hashimoto's Thyroiditis-Associated Acute Renal Failure and Pitfalls of eGFR Interpretation in Thyroid Diseases

The authors describe a patient with severe hypothyroidism due to Hashimoto's thyroiditis and describe the pitfalls of estimated glomerular filtration rate interpretation in such cases.

LEARNING POINTS

Manifest hypothyroidism can lead to a functional reduction in glomerular filtration rates (GFRs).Restoration of a normal thyroid stimulating hormone (TSH) will also restore kidney function.Cystatin C-based GFR formulas will overestimate renal filtration rates in cases of hypothyroidism and underestimate GFRs in cases of hyperthyroidism.

CytoResc - "CytoSorb" Rescue for critically ill patients undergoing the COVID-19 Cytokine Storm: A structured summary of a study protocol for a randomized controlled trial

OBJECTIVES

Approximately 8 - 10 % of COVID-19 patients present with a serious clinical course and need for hospitalization, 8% of hospitalized patients need ICU-treatment. Currently, no causal therapy is available and treatment is purely supportive. The main reason for death in critically ill patients is acute respiratory failure. However, in a number of patients a severe hyperinflammatory response with excessively elevated proinflammatory cytokines causes vasoplegic shock resistant to vasopressor therapy. A new polystyrene-based hemoadsorber (CytoSorb®, Cytosorbents Inc., New Jersey, USA) has been shown to adsorb effectively cytokines and other middle molecular weight toxins this way reducing their blood concentrations. This has been routinely used in clinical practice in the EU for other conditions where a cytokine storm occurs and an observational study has just been completed on COVID-19 patients. We hypothesized that the extracorporeal elimination of cytokines in critically ill COVID-19 patients with suspected hyperinflammation and shock may stabilize hemodynamics and improve outcome. The primary endpoint is time until resolution of vasoplegic shock, which is a well implemented, clinically relevant endpoint in critical care studies.

TRIAL DESIGN

Phase IIb, multicenter, prospective, open-label, randomized, 1:1 parallel group pilot study comparing the additional use of "CytoSorb" to standard of care without "CytoSorb".

PARTICIPANTS

Patients are recruited from the Intensive Care Units (ICUs) of 7 participating centers in Germany (approximately 10 ICUs). All patients aged 18- 80 with positive polymerase chain reaction (PCR) test for SARS-CoV-2, a C-reactive protein (CRP) ≥ 100 mg/l, a Procalcitonin (PCT) < 2 ng/l, and suspected cytokine storm defined via a vasoplegic shock (Norepinephrine > 0.2 μg/min/kg to achieve a Mean Arterial Pressure ≥ 65mmHg). Patients are included irrespective of indication for renal replacement therapy. Suspected or proven bacterial cause for vasoplegic shock is a contraindication.

INTERVENTION AND COMPARATOR

Within 24 hours after meeting the inclusion criteria patients will be randomized to receive either standard of care or standard of care and additional "CytoSorb" therapy via a shaldon catheter for 3-7 days. Filter exchange is done every 24 hours. If patients receive antibiotics, an additional dose of antibiotics is administered after each change of "CytoSorb" filter in order to prevent underdosing due to "CytoSorb" treatment.

MAIN OUTCOMES

Primary outcome is time to resolution of vasoplegic shock (defined as no need for vasopressors for at least 8 hours in order to sustain a MAP ≥ 65mmHg) in days. Secondary outcomes are 7 day mortality after fulfilling the inclusion criteria, mortality until hospital discharge, Interleukin-6 (IL-6) measurement on day 1 and 3, need for mechanical ventilation, duration of mechanical ventilation, duration of ICU-stay, catecholamine dose on day 1/2/3 after start of "CytoSorb" and acute kidney injury.

RANDOMIZATION

An electronic randomization will be performed using the study software secuTrial® administered by the Clinical Study Center (CSC) of the Charité - Universitätsmedizin Berlin, Germany. Randomization is done in blocks by 4 stratified by including center.

BLINDING (MASKING)

The trial will be non-blinded for the clinicians and patients. The statistician will receive a blinded data set, so that all analyses will be conducted blinded.

NUMBERS TO BE RANDOMIZED (SAMPLE SIZE)

As this is a pilot study with the goal to examine the feasibility of the study design as well as the intervention effect, no formal sample size calculation was conducted. A total number of approximately 80-100 patients is planned (40-50 patients per group). Safety assessment is done after the inclusion of each 10 patients per randomization group.

TRIAL STATUS

Please see the study protocol version from April 24 2020. Recruitment of patients is still pending.

TRIAL REGISTRATION

The study was registered on April 27 2020 in the German Registry of Clinical Trials (DRKS) under the number DRKS00021447.

FULL PROTOCOL

The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol.

Control of neutrophil influx during peritonitis by transcriptional cross-regulation of chemokine CXCL1 by IL-17 and IFN-γ

Neutrophil infiltration is a hallmark of peritoneal inflammation, but mechanisms regulating neutrophil recruitment in patients with peritoneal dialysis (PD)-related peritonitis are not fully defined. We examined 104 samples of PD effluent collected during acute peritonitis for correspondence between a broad range of soluble parameters and neutrophil counts. We observed an association between peritoneal IL-17 and neutrophil levels. This relationship was evident in effluent samples with low but not high IFN-γ levels, suggesting a differential effect of IFN-γ concentration on neutrophil infiltration. Surprisingly, there was no association of neutrophil numbers with the level of CXCL1, a key IL-17-induced neutrophil chemoattractant. We investigated therefore the production of CXCL1 by human peritoneal mesothelial cells (HPMCs) under in vitro conditions mimicking clinical peritonitis. Stimulation of HPMCs with IL-17 increased CXCL1 production through induction of transcription factor SP1 and activation of the SP1-binding region of the CXCL1 promoter. These effects were amplified by TNFα. In contrast, IFN-γ dose-dependently suppressed IL-17-induced SP1 activation and CXCL1 production through a transcriptional mechanism involving STAT1. The SP1-mediated induction of CXCL1 was also observed in HPMCs exposed to PD effluent collected during peritonitis and containing IL-17 and TNFα, but not IFN-γ. Supplementation of the effluent with IFN-γ led to a dose-dependent activation of STAT1 and a resultant inhibition of SP1-induced CXCL1 expression. Transmesothelial migration of neutrophils in vitro increased upon stimulation of HPMCs with IL-17 and was reduced by IFN-γ. In addition, HPMCs were capable of binding CXCL1 at their apical cell surface. These observations indicate that changes in relative peritoneal concentrations of IL-17 and IFN-γ can differently engage SP1-STAT1, impacting on mesothelial cell transcription of CXCL1, whose release and binding to HPMC surface may determine optimal neutrophil recruitment and retention during peritonitis. © 2020 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Glucose Degradation Products and Peritoneal Membrane Function

Background

The bioincompatibility of peritoneal dialysis fluids (PDF) in current use has been partially attributed to the presence of glucose degradation products (GDPs), which are generated during heat sterilization of PDF. Several of the GDPs have been identified and we have recently demonstrated that these GDPs per se may impair the viability and function of human peritoneal mesothelial cells (HPMC) in vitro. It is also possible that GDP-related toxicity is further exacerbated by the milieu of PDF. We review the current literature on GDP and present the results of experiments comparing the impact of heat- and filter-sterilized PDF on the viability and function of HPMC.

Methods

Peritoneal dialysis fluids with low (1.5%) and high (4.25%) glucose concentrations were laboratory prepared according to the standard formula and sterilized either by heat (H-PDF; 121°C, 0.2 MPa, 20 minutes) or filtration (F-PDF; 0.2 μ). The buildup of GDP was confirmed by UV absorbance at 284 nm. Confluent HPMC monolayers were exposed to these solutions mixed 1:1 with standard M199 culture medium. After 24 hours, cell viability was assessed with the MTT assay, and interleukin-1β–stimulated monocyte chemotactic protein-1 (MCP-1) release with specific immunoassay.

Results

Exposure of HPMC to H-PDF resulted in a significant decrease in cell viability, with solutions containing 4.25% glucose being more toxic than 1.5% glucose-based PDF (27.4% ± 3.4% and 53.4% ± 11.0% of control values, respectively). In contrast, viability of HPMC exposed to F-PDF was not different from that of control cells. Moreover, treatment with H-PDF impaired the release of MCP-1 from HPMC to a significantly greater degree compared to F-PDF (17.4% and 24.9% difference for low and high glucose PDF, respectively).

Conclusions

Exposure of HPMC to H-PDF significantly impairs cell viability and the capacity for generating MCP-1 compared to F-PDF. This effect is likely to be mediated by GDPs present in H-PDF but not in F-PDF.

Lessons from Basic Research for Pd Treatment

Over the past 30 years, the focus of peritoneal dialysis research has changed from the technical issues related to the establishment of clinical peritoneal dialysis to complex problems of peritoneal membrane biology. Here, we present how these research topics developed, discuss their significance for clinical science, and outline future challenges for peritoneal dialysis research.

Glucose Degradation Products and the Peritoneal Mesothelium

Conventional heat-sterilized, glucose-based peritoneal dialysis (PD) fluids contain significant amounts of glucose degradation products (GDPs) such as aldehydes and dicarbonyl compounds (glyoxal, methylglyoxal). These GDPs have been shown to impair cell functions in various in vitro experimental models. In peritoneal mesothelial cells, GDPs dose-dependently inhibit cell proliferation and mediator synthesis. In addition, some GDPs potently promote generation of advanced glycation end-products (AGEs). Immunohistochemistry finds AGEs in the peritoneal membrane of chronic continuous ambulatory peritoneal dialysis (CAPD) patients, suggesting that peritoneal AGE accumulation may be involved in chronic peritoneal fibrosis.

The formation of GDPs might be prevented by filter-sterilization of PD fluids. Another option is to separate the glucose and the buffer system in dual-chambered or multi-chambered containers. In these systems, the glucose is kept in a separate compartment at high concentration and very low pH—both conditions being known to minimize the degree of glucose decomposition during autoclaving. Initial experimental evidence suggests that these novel, multi-chambered fluids significantly improve in vitro biocompatibility; however, the clinical relevance of these results remains to be established in clinical trials.

FirstIn VitroandIn VivoExperiences with Stay·Safe Balance, A pH-Neutral Solution in a Dual-Chambered Bag

In addition to low pH and high osmolarity, glucose degradation products (GDPs) are considered to play a major role in the bioincompatibility of peritoneal dialysis fluids (PDFs). The formation of GDPs can be reduced by separating the glucose component of the solution (kept at very low pH) from the lactate component of the solution (kept at alkaline pH) during sterilization and storage. This development has been achieved by the use of a dual-chambered bag. Immediately before infusion, the seam between the two chambers is opened, and the contents are mixed. The result is a fluid with a more physiologic pH in the range 6.8 – 7.4.

Concentrations of 3-deoxyglucosone (3-DG), methyl-glyoxal (MG), acetaldehyde (AA), and formaldehyde (FA) in Stay·Safe Balance (Fresenius Medical Care, Bad Homburg, Germany) were remarkably reduced when compared to conventional PD solution [conventional PDF (1.5% glucose): 172 μmol/L, 6 μmol/L, 152 μmol/L, and 7 μmol/L respectively; Stay·Safe Balance (1.5% glucose): 42 μmolL, < 1 μmol/L, < 2 μmol/L, and < 3 μmol/L respectively; conventional PDF (4.25% glucose): 324 μmol/L, 10 μmol/L, 182 μmol/L, and 13 μmol/L respectively; Stay·Safe Balance (4.25% glucose): 60 μmol/L, < 1 μmol/L, < 2 μmol/L, and < 3 μmol/L respectively).

Human peritoneal mesothelial cells (HPMCs) were exposed to a control solution, a conventional PDF [CAPD 2, 1.5% glucose (Fresenius Medical Care, Bad Homburg, Germany)], and Stay·Safe Balance, either in a co-incubation model (24-hour PDF exposure) or in a pre-incubation model (30-min PDF exposure), followed by 24-hour recovery in culture medium. Interleukin-1β (IL-1β)–stimulated (1 ng/mL) IL-6 secretion from HPMCs was assessed by ELISA. Exposure of HPMCs to conventional PDF resulted in a significant reduction in IL-6 release, which was fully restored following exposure to Stay·Safe Balance. In addition to the short-term investigations, long-term in vitro studies were also carried out. All fluids had near-neutral pH and were changed every second day. After 1, 3, 5, 7, 10, and 13 days of exposure, cell viability was assessed. Whereas exposure to conventional PDF resulted in a significant reduction in HPMC viability after just 3 – 5 days, no significant toxicity of filter-sterilized or dual-chambered fluid was observed for up to 13 days.

An observational study with 9 patients suggested that the efficacy of Stay·Safe Balance is equivalent to that of conventional solution. However, even short-term treatment (8 ± 1 weeks) with this more biocompatible solution seems to improve mesothelial cell mass as indicated by a rise in cancer antigen 125 (CA125) from a baseline of 47 ± 37 U/ min to 172 ± 90 U/min.

Our data indicate that Stay·Safe Balance may help to better preserve peritoneal membrane cell function. An ongoing European multicenter study is expected to confirm these results.

Effects of Peritoneal Dialysis Solutions on the Peritoneal Membrane: Clinical Consequences

This review provides an overview of recent studies that show the clinical significance of biocompatibility of peritoneal dialysis fluids.

Technological Advances in Peritoneal Dialysis Research Peritoneal Cell Culture: Fibroblasts

Fibroblasts have been traditionally viewed as providing little more than a structural lattice for other cell types. However, recent data indicate that fibroblasts play a key and early role in many pathophysiological processes, including inflammation, fibrosis, and neoplasia. Moreover, depending on the anatomical location, fibroblasts display significant functional heterogeneity. Therefore, it is important to study the subpopulation of fibroblasts derived exactly from the organ of interest rather than to extrapolate the observations made in other fibroblast subsets. Cell culture provides a powerful tool for studying the role of fibroblasts in various contexts. In this review, we describe procedures for establishing and identifying primary cultures of human peritoneal fibroblasts. We also briefly discuss the potential involvement of peritoneal fibroblasts in peritoneal pathology.

The Role of the Glyoxalase Pathway in Reducing Mesothelial Toxicity of Glucose Degradation Products

Background

The glucose degradation products (GDP) present in conventional peritoneal dialysis fluids (PDF) may exert adverse effects toward human peritoneal mesothelial cells (HPMC). Some GDP can be detoxified by the glyoxalase/glutathione pathway. It has been shown that the addition of glyoxalase I (GLO-I) and reduced glutathione (GSH) to PDF effectively eliminates GDP. We have therefore examined the GLO-I/GSH system in HPMC and assessed the impact of GLO-I/GSH-treated PDF on the viability and function of HPMC.

Methods

Heat-sterilized PDF (H-PDF) was incubated in the presence or absence of GLO-I and GSH for 1 hour at 37°C, and then mixed with an equal volume of serum-free M199 medium and applied to HPMC in culture. After 24 hours, HPMC were assessed for viability, the release of interleukin-6, GLO-I activity, and cellular glutathione. The effects were compared to those exerted by filter-sterilized PDF (F-PDF), which was devoid of GDP.

Results

Exposure of HPMC to H-PDF resulted in reduced GLO-I activity, GSH depletion, and a decrease in cell viability. Pretreatment of H-PDF with either a combination of GLO-I and GSH or GSH alone markedly reduced inhibitory effects of H-PDF toward HPMC, as measured by cell viability and interleukin-6 generation. Exposure of HPMC to the GSH precursor L-2-oxothiazolidine-carboxylic acid increased cellular GSH and prevented the loss of GLO-I activity in response to H-PDF.

Conclusions

Exposure to conventional GDP-rich PDF impairs the activity of the glyoxalase/glutathione system in HPMC. Pretreatment of PDF with GSH or replenishment of cellular GSH protects HPMC against GDP-mediated toxicity.

Quality of design and reporting of animal research in peritoneal dialysis: A scoping review

The concerns about reproducibility and validity of animal studies are partly related to poor experimental design and reporting. Here, we undertook a scoping review of the literature to determine the extent and quality of reporting of animal studies on peritoneal dialysis (PD). Online databases were searched to identify 567 relevant original articles published between 1979 and 2018. These were analyzed with respect to bibliographic parameters and general aspects of animal experimentation. A subgroup of 120 studies was analyzed in detail in terms of the impact on the reporting quality of the Animal Research: Reporting of In Vivo Experiments (ARRIVE) guidelines for animal studies. The number of animal studies on PD increased continuously over the years with a thematic shift toward long-term preservation of the peritoneum as a dialyzing organ. There were significant deficiencies in research design with the lack of sample size estimation, randomization, and blinding being the commonest shortcomings. The description of animal numbers, housing conditions, use of medication, and statistical analysis was incomplete. The introduction in 2010 of the ARRIVE guidelines produced very little improvement in the completeness of reporting regardless of journal impact factor. The animal studies on PD suffer from deficits in experimental protocols and transparent reporting. These drawbacks need to be corrected to ensure high-quality and much-needed animal research in PD.

Elimination of glutamate using CRRT for 72 h in patients with post-cardiac arrest syndrome: A randomized clinical pilot trial

AIM

Glutamine and glutamate are major mediators of secondary brain cell death during post-cardiac arrest syndrome. As there is an equilibrium between brain tissue and plasma concentrations of glutamine and glutamate, their elimination from systemic circulation by extracorporeal blood purification may ultimately lead to reduced secondary cell death in the brain. We hypothesized that systemic glutamine and glutamate can be significantly reduced by continuous venovenous hemodiafiltration (CVVHDF).

METHODS

This was a prospective, randomized clinical trial in post cardiac-arrest survivors evaluating standard of care or additional CVVHDF over 72 h immediately after admission. Glutamine and glutamate plasma concentrations were analyzed at eight time points in both groups. Primary endpoint was reduction of glutamine and glutamate plasma concentrations. The trial has been registered at clinical trial.gov (NCT02963298).

RESULTS

In total, 41 patients were randomized over a period of 12 months (control n = 21, CVVHDF n = 20). The primary aim reduction of glutamine and glutamate plasma concentrations by CVVHDF, was not achieved; both groups-maintained concentrations within a normal range over the study period (glutamate: 4.7-11.1 mg/dL; glutamine: 0.2-3.7 mg/dL). However, post-filter concentrations of glutamine and glutamate in CRRT patients were significantly decreased as compared to pre-filter concentrations (glutamate: pre-filter median 8.85 mg/dL IQR 7.1-9.6; post-filter 0.95 mg/dL IQR 0.5-2; p < 0.001; glutamine: pre-filter 0.7 mg/dL IQR 0.6-1; post-filter 0.2 mg/dL IQR 0-0.2; p < 0.001).

CONCLUSION

In this trial, CVVHDF was not able to statistically significantly lower systemic plasma glutamine and glutamate levels. Post-cardiac arrest patients had plasma glutamine and glutamate levels within the normal range.

IL-17 in Peritoneal Dialysis-Associated Inflammation and Angiogenesis: Conclusions and Perspectives

Long-term peritoneal dialysis (PD) is associated with peritoneal membrane remodeling. This includes changes in peritoneal vasculature, which may ultimately lead to inadequate solute and water removal and treatment failure. The potential cause of such alterations is chronic inflammation induced by repeated episodes of infectious peritonitis and/or exposure to bioincompatible PD fluids. While these factors may jeopardize the peritoneal membrane integrity, it is not clear why adverse peritoneal remodeling develops only in some PD patients. Increasing evidence points to the differences that occur between patients in response to the same invading microorganism and/or the differences in the course of inflammatory reaction triggered by different species. Such differences may be related to the involvement of different inflammatory mediators. Here, we discuss the potential role of IL-17 in these processes with emphasis on its impact on peritoneal mesothelial cells and peritoneal vascularity.

Epithelial-to-Mesenchymal Transition and Migration of Human Peritoneal Mesothelial Cells Undergoing Senescence

BACKGROUND

Epithelial-to-mesenchymal transition (EMT) of human peritoneal mesothelial cells (HPMCs) contributes to fibrotic thickening of the peritoneum that develops in patients on peritoneal dialysis (PD). The process is thought to be largely mediated by transforming growth factor-beta (TGF-β). As TGF-β has also been implicated in senescence of HPMCs, we have performed an exploratory study to examine if senescent HPMCs can undergo EMT.

METHODS

Omentum-derived HPMCs were rendered senescent by repeated passages in culture. Features of EMT were assessed by immunostaining and quantitative polymerase chain reaction (qPCR) at various stages of the HPMC lifespan and after treatment with or without TGF-β. The motility of HPMCs was assessed in a scratch wound migration assay.

RESULTS

Replicative senescence of HPMCs was associated with a gradual increase in the constitutive expression of EMT markers, including increased production of extracellular matrix proteins. However, senescent HPMCs also retained epithelial cell features such as cytokeratin, calretinin, and E-cadherin and showed decreased, rather than increased, motility. In contrast, exposure to TGF-β resulted in an up-regulation of mesenchymal markers and down-regulation of epithelial markers. Such effects of TGF-β occurred both in young and senescent cells, although they were less pronounced in senescence.

CONCLUSIONS

Senescence of HPMCs is associated with spontaneous development of several EMT features. At the same time, senescent HPMCs preserve epithelial cell-like characteristics and are less prone to develop a full EMT phenotype in response to TGF-β. These observations may support the concept of cellular senescence being antagonistically pleiotropic with regard to EMT.

Peritoneal dialysis catheter leakage following intermittent vacuum therapy

Peripheral arterial disease and diabetic foot syndrome are common comorbidities in dialysis patients. These conditions are treated with intermittent vacuum therapy in order to increase angiogenesis and perfusion. Some devices encase the lower extremities up to the abdomen. Here we report the case of a patient who had performed peritoneal dialysis for 2 years without complications. Following postoperative intermittent vacuum therapy, he presented with extensive catheter leakage. Ultimately the patient had to be switched to haemodialysis and the catheter had to be removed. This case exemplifies that peritoneal dialysis patients have a substantial risk for noninfectious catheter-related complications using vacuum therapy.

[Regional citrate anticoagulation in renal replacement therapy in the intensive care station : Recommendations from the renal section of the DGIIN, ÖGIAIN and DIVI]

BACKGROUND

Regional citrate anticoagulation (RCA) in continuous renal replacement therapy can effectively anticoagulate dialysis circuits without having adverse effects on systemic heparin application. In particular, in continuous renal replacement therapy RCA is well established and represents a safe procedure with longer filter lifetimes and fewer bleeding complications.

OBJECTIVES

To provide guidance on the indications, advantages and disadvantages, and use of RCA, current recommendations from the renal section of the DGIIN (Deutschen Gesellschaft für Internistische Intensivmedizin und Notfallmedizin), ÖGIAIN (Österreichischen Gesellschaft für Internistische und Allgemeine Intensivmedizin und Notfallmedizin) and DIVI (Deutschen Interdisziplinären Vereinigung für Intensiv- und Notfallmedizin) are stated.

MATERIALS AND METHODS

The recommendations in this paper are based on the current KDIGO (Kidney Disease: Improving Global Outcomes) guidelines, other published guidelines and protocols as well as the expert knowledge and clinical experience of the authors.

RESULTS

The use of commercially available machines with coupled pumps and integrated safety features, effective personal training and standardized protocols for clinical usage (SOP) is particularly important for the safe clinical use of RCA in renal replacement therapy. Contrary to previous recommendations, even liver failure or shock with lactic acidosis may no longer be an absolute contra-indication for RCA. However, these particular patients have to be carefully monitored for signs of citrate accumulation.

[Metabolic management and nutrition in critically ill patients with renal dysfunction : Recommendations from the renal section of the DGIIN, ÖGIAIN, and DIVI]

BACKGROUND

Intensive care patients with renal failure or insufficiency comprise a heterogeneous group of subjects with widely differing metabolic patterns and nutritional requirements. They include subjects with various stages of acute kidney injury (AKI), acute-on-chronic renal failure (A-CKD), without/with renal replacement therapy (RRT), chronic kidney disease (CKD), and subjects on regular hemodialysis or peritoneal dialysis therapy (HD/PD).

GOALS

Development of recommendations by the renal section of DGIIN (Deutsche Gesellschaft für Internistische Intensivmedizin und Notfallmedizin), ÖGIAIN (Österreichische Gesellschaft für Internistische und Allgemeine Intensivmedizin und Notfallmedizin) and DIVI (Deutsche Interdisziplinäre Vereinigung für Intensiv- und Notfallmedizin) for the metabolic management and the planning, indication, implementation, and monitoring of nutrition therapy in this heterogeneous group of patients.

MATERIALS AND METHODS

The recommendations are based on recent evidence and current recommendations of DGEM (Deutsche Gesellschaft für Ernährungsmedizin), ASPEN (American Society for Parenteral and Enteral Nutrition) and ESPEN (European Society for Clinical Nutrition and Metabolism) and also the KDGIO (Kidney Disease: Improving Global Outcomes) clinical practice guidelines for AKI and the expert knowledge and clinical experience of the authors.

RESULTS

Nutrition support in these patient groups is not fundamentally different from that in other disease states but must consider the multiple variations in metabolism and nutrient requirements. Nutrition therapy must be adapted to the stage of disease and especially, in those patients on RRT. Nutritional needs can differ widely between patients but also in the same patient during the course of the disease.

CONCLUSIONS

Thus, the patient with renal failure requires an individualized approach in nutrition support and because of the altered metabolism of many nutrients and intolerances for electrolytes and fluids, the nutrition support in patients with renal insufficiency requires close clinical and laboratory monitoring.

Side Effects of Hybrid Liver Support Therapy: TNF-α Liberation in Pigs, Associated with Extracorporeal Bioreactors

During acute liver failure, hybrid liver support therapy could serve as a bridge to liver transplantation. In this desired temporary use, immune competent cell responses, such as the production of cytokines, might be of limiting relevance. We have investigated the Tumor Necrosis Factor-α (TNF) liberation in two models using pigs, connected with an extracorporeal bioreactor with homologous hepatocytes: TNF liberation was measured in arterial plasma during a 4 day perfusion time in untreated animals, model (i), and during short term perfusion of hepatectomized pigs in model (ii). Animals four days after catheter implantation in model (i) had TNF values of < 5 pg/ml. After connecting the system without hepatocytes, TNF rose to 9.7 ± 2 within 120 min and rose further to 32.6 ± 6 pg/ml within 4 hours after filling the system with the homologous hepatocytes. After 24 hours of continuous perfusion and during four days of perfusion, the TNF levels were lowered to baseline levels. In model (ii), TNF rose to 220 ± 130 pg/ml within 180 min and decreased to 110 ± 10 pg/ml within six hours, whereas controls without hepatocytes showed mean levels with a maximum of 120 ± 20 pg/ml. In both models, there was no correlation between TNF levels and clinical abnormalities such as fever or shock symptoms. There is evidence for an activation of blood cells during experimental extracorporeal hybrid support. No typical side effects were, however, observed. Thus, TNF mediated extracorporeal cell activation does not appear to limit the application of homologous hybrid liver support therapy.

[Prevention of acute kidney injury in critically ill patients : Recommendations from the renal section of the DGIIN, ÖGIAIN and DIVI]

BACKGROUND

Acute kidney injury (AKI) has both high mortality and morbidity.

OBJECTIVES

To prevent the occurrence of AKI, current recommendations from the renal section of the DGIIN (Deutschen Gesellschaft für Internistische Intensivmedizin und Notfallmedizin), ÖGIAIN (Österreichischen Gesellschaft für Internistische und Allgemeine Intensivmedizin und Notfallmedizin) and DIVI (Deutschen Interdisziplinären Vereinigung für Intensiv- und Notfallmedizin) are stated.

MATERIALS AND METHODS

The recommendations stated in this paper are based on the current Kidney Disease Improving Global Outcomes (KDIGO) guidelines, the published statements of the "Working Group on Prevention, AKI section of the European Society of Intensive Care Medicine" and the expert knowledge and clinical experience of the authors.

RESULTS

Currently there are no approved clinically effective drugs for the prevention of AKI. Therefore the mainstay of prevention is the optimization of renal perfusion by improving the mean arterial pressure (>65 mm Hg, higher target may be considered in hypertensive patients). This can be done by vasopressors, preferably norepinephrine and achieving or maintaining euvolemia. Hyperhydration that can lead to AKI itself should be avoided. In patients with maintained diuresis this can be done by diuretics that are per se no preventive drug for AKI. Radiocontrast enhanced imaging should not be withheld from patients at risk for AKI; if indicated, however, the contrast media should be limited to the smallest possible volume.

Variables Associated with the Assessment of Systemic Tumor Necrosis Factor Alpha Levels during Hemodialysis

Conflicting results have been published concerning the systemic induction of the cytokine tumor necrosis factor alpha (TNFα) during hemodialysis (HD). We therefore evaluated in vitro TNFα production in whole blood as well as in vivo variability of TNFα levels in patients on long-term HD. Whole blood was incubated at room temperature (RT) with or without exogenously added endotoxin (ET), and plasma-TNFα was measured after 5, 30, 120, 240, and 960 min by specific enzyme immunoassay. Additionally, plasma-TNFα before and after 120 and 240 min HD was studied longitudinally once a week over a period of 4 weeks in 36 patients on Cuprophan® (CU, n=23) or polysulfone-F60 (PSu, n=13) HD. Mean plasma TNFα levels in vitro rose from (mean) 8 pg/ml after 5 min to 12 pg/ml (120′) and 32 pg/ml (960′) even without ET addition, and to 18 pg/ml (after 120′) and 88 pg/ml (after 960′) when 0.1 μg/ml ET were added. Pre-dialytic as well as intradialytic TNFα levels in patients showed high intra-individual variability. A substantial (> 100%) increase in plasma TNFα was observed during only 14 out of 84 treatments with CU and 20 out of 47 with PSu, however, the increase in TNFα was not statistically significant in either group. We conclude that the sampling procedure, if not carefully standardized, is a potential source of artifacts with regard to “systemic” TNFα levels. The high intra and inter-individual variability of plasma TNFα suggests that results of cross-sectional studies are questionable.

Leukotriene Release from Neutrophils of Patients on Hemodialysis with Cellulose Membranes

The role of cytokines in patients with chronic renal failure is currently under investigation. We therefore studied the release of leukotriene B4 (LTB4) from polymorphonuclear leukocytes (PMN) in stable dialysis patients treated with two different cellulose membranes, Cuprophan and Hemophan®, a modified cellulose with less complement activation. Six patients were treated for four weeks with Cuprophan then switched to Hemophan® for another four weeks. Before and after the last treatment of each period, PMN were separated from 20 ml heparinized blood by FICOLL density gradient centrifugation. Portions of 5x106 PMN were resuspended in Hanks' buffer and stimulated for 5 minutes with calcium ionophore A23187 (5 /μg/ml). LTB4 in cell supernatants was determined by specific radioimmunoassay. PMN from dialysis patients before HD released significantly (p<0.01) more LTB4 than healthy donors. No significant difference between pre- and post-dialysis values was observed with Cuprophan or Hemophan® dialyzers. Our data suggest that the acute effects of blood membrane interaction with either complement activating or non-activating dialyzers do not lead to changes in post-dialysis leukotriene metabolism, but leukotriene production is enhanced chronically in dialysis patients.

Uremic Toxicity: Present State of the Art

The uremic syndrome is a complex mixture of organ dysfunctions, which is attributed to the retention of a myriad of compounds that under normal condition are excreted by the healthy kidneys (uremic toxins). In the area of identification and characterization of uremic toxins and in the knowledge of their pathophysiologic importance, major steps forward have been made during recent years. The present article is a review of several of these steps, especially in the area of information about the compounds that could play a role in the development of cardiovascular complications. It is written by those members of the Uremic Toxins Group, which has been created by the European Society for Artificial Organs (ESAO). Each of the 16 authors has written a state of the art in his/her major area of interest.

Correlation between HSP-72 Expression and IL-8 Secretion in Human Mesothelial Cells

Background

Cytotoxicity of peritoneal dialysis fluid (PDF) and peritoneal inflammation are currently regarded as the two major culprits for chronic mesothelial injury and peritoneal membrane failure. In this study, we correlated induction of HSP-72, as a marker of the cellular stress response, to secretion of IL-8, as a marker for pro-inflammatory cytokines, in mesothelial cells upon sublethal PDF exposure.

Methods

Primary omental cell cultures of human mesothelial cells were subjected to sublethal PDF exposure times (CAPD2, Fresenius, Germany). At the end of a 24 hour recovery period, induction of HSP-72 in the cell homogenate and IL-8 secretion in the supernatant was assessed by immunodensitometry and ELISA, respectively.

Results

PDF exposure times from 15 min to 60 min resulted in progressively increased HSP-72 expression levels (267 vs 320 vs 419% of controls, p<0.05 vs controls) as well as increased IL-8 secretion (323 vs 528 vs 549% of controls, p<0.05 vs controls) with full cell viability (MTT unchanged to control). HSP-72 expression was statistically significantly correlated with IL-8 secretion. Conclusions: The significant correlation between HSP-72 expression and IL-8 secretion suggests that the regulation of pro-inflammatory pathways in mesothelial cells exposed to PDF may represent an integral part of their stress response. Future studies to investigate the cellular regulatory mechanism involved are warranted.

The effect of a novel extracorporeal cytokine hemoadsorption device on IL-6 elimination in septic patients: A randomized controlled trial

Objective

We report on the effect of hemoadsorption therapy to reduce cytokines in septic patients with respiratory failure.

Methods

This was a randomized, controlled, open-label, multicenter trial. Mechanically ventilated patients with severe sepsis or septic shock and acute lung injury or acute respiratory distress syndrome were eligible for study inclusion. Patients were randomly assigned to either therapy with CytoSorb hemoperfusion for 6 hours per day for up to 7 consecutive days (treatment), or no hemoperfusion (control). Primary outcome was change in normalized IL-6-serum concentrations during study day 1 and 7.

Results

97 of the 100 randomized patients were analyzed. We were not able to detect differences in systemic plasma IL-6 levels between the two groups (n = 75; p = 0.15). Significant IL-6 elimination, averaging between 5 and 18% per blood pass throughout the entire treatment period was recorded. In the unadjusted analysis, 60-day-mortality was significantly higher in the treatment group (44.7%) compared to the control group (26.0%; p = 0.039). The proportion of patients receiving renal replacement therapy at the time of enrollment was higher in the treatment group (31.9%) when compared to the control group (16.3%). After adjustment for patient morbidity and baseline imbalances, no association of hemoperfusion with mortality was found (p = 0.19).

Conclusions

In this patient population with predominantly septic shock and multiple organ failure, hemoadsorption removed IL-6 but this did not lead to lower plasma IL-6-levels. We did not detect statistically significant differences in the secondary outcomes multiple organ dysfunction score, ventilation time and time course of oxygenation.

Thy-1+/- fibroblast subsets in the human peritoneum

Fibrotic thickening of the peritoneum develops in patients receiving peritoneal dialysis (PD) for renal failure. For unknown reasons, however, in some patients it progresses to extensive fibrosis that compromises dialysis capacity of the peritoneum. It is increasingly clear that fibroblasts display large heterogeneity not only between but also within tissues. Differential surface expression of thymocyte differentiation antigen 1 (Thy-1) has been shown to identify functionally distinct fibroblast subsets in several organs. Here, we isolated Thy-1^+/- subsets of human peritoneal fibroblasts (HPFB) and analyzed them in terms of profibrotic myofibroblast features. In healthy individuals, Thy-1⁺ cells constituted ~45% of the HPFB population found in the greater omentum but were not detected in the parietal peritoneum. When propagated in culture and compared with Thy-1^- cells, omentum-derived Thy-1⁺ HPFB consistently displayed an increased expression of α-smooth muscle actin, collagen I, and transforming growth factor-β1. They also showed greater proliferation capacity and enhanced contractile properties. The number of Thy-1⁺ HPFB increased significantly in PD patients and made up more than 70 and 95% of all HPFB found in the omentum and parietal peritoneum, respectively. These data indicate that the expansion of Thy-1⁺ fibroblasts may contribute to fibrotic thickening of the peritoneal membrane during PD.

Management of patients at risk of acute kidney injury

Acute kidney injury (AKI) is a multifaceted syndrome that occurs in different settings. The course of AKI can be variable, from single hit and complete recovery, to multiple hits resulting in end-stage renal disease. No interventions to improve outcomes of established AKI have yet been developed, so prevention and early diagnosis are key. Awareness campaigns and education for health-care professionals on diagnosis and management of AKI-with attention to avoidance of volume depletion, hypotension, and nephrotoxic interventions-coupled with electronic early warning systems where available can improve outcomes. Biomarker-based strategies have not shown improvements in outcome. Fluid management should aim for early, rapid restoration of circulatory volume, but should be more limited after the first 24-48 h to avoid volume overload. Use of balanced crystalloid solutions versus normal saline remains controversial. Renal replacement therapy should only be started on the basis of hard criteria, but should not be delayed when criteria are met. On the basis of recent evidence, the risk of contrast-induced AKI might be overestimated for many conditions.

IL-6 Trans-Signaling Links Inflammation with Angiogenesis in the Peritoneal Membrane

Vascular endothelial growth factor (VEGF) is implicated in the peritoneal membrane remodeling that limits ultrafiltration in patients on peritoneal dialysis (PD). Although the exact mechanism of VEGF induction in PD is unclear, VEGF concentrations in drained dialysate correlate with IL-6 levels, suggesting a link between these cytokines. Human peritoneal mesothelial cells (HPMCs), the main source of IL-6 and VEGF in the peritoneum, do not bear the cognate IL-6 receptor and are thus unable to respond to classic IL-6 receptor signaling. Here, we investigated whether VEGF release by HPMCs is controlled by IL-6 in combination with its soluble receptor (IL-6 trans-signaling). Although treatment with either IL-6 or soluble IL-6 receptor (sIL-6R) alone had no effect on VEGF production, stimulation of HPMCs with IL-6 in combination with sIL-6R promoted VEGF expression and secretion through a transcriptional mechanism involving STAT3 and SP4. Conditioned medium from HPMCs cultured with IL-6 and sIL-6R promoted angiogenic endothelial tube formation, which could be blocked by silencing SP4. In vivo, induction of peritoneal inflammation in wild-type and IL-6-deficient mice showed IL-6 involvement in the control of Sp4 and Vegf expression and new vessel formation, confirming the role of IL-6 trans-signaling in these processes. Taken together, these findings identify a novel mechanism linking IL-6 trans-signaling and angiogenesis in the peritoneal membrane.

Activation of nuclear factor of activated T cells 5 in the peritoneal membrane of uremic patients

Peritoneal inflammation and fibrosis are responses to the uremic milieu and exposure to hyperosmolar dialysis fluids in patients on peritoneal dialysis. Cells respond to high osmolarity via the transcription factor nuclear factor of activated T cells (NFAT5). In the present study, the response of human peritoneal fibroblasts to glucose was analyzed in vitro. Expression levels of NFAT5 and chemokine (C-C motif) ligand (CCL2) mRNA were quantified in peritoneal biopsies of five nonuremic control patients, five uremic patients before PD (pPD), and eight patients on PD (oPD) using real-time PCR. Biopsies from 5 control patients, 25 pPD patients, and 25 oPD patients were investigated using immunohistochemistry to detect the expression of NFAT5, CCL2, NF-κB p50, NF-κB p65, and CD68. High glucose concentrations led to an early, dose-dependent induction of NFAT5 mRNA in human peritoneal fibroblasts. CCL2 mRNA expression was upregulated by high concentrations of glucose after 6 h, but, most notably, a concentration-dependent induction of CCL2 was present after 96 h. In human peritoneal biopsies, NFAT5 mRNA levels were increased in uremic patients compared with nonuremic control patients. No significant difference was found between the pPD group and oPD group. CCL2 mRNA expression was higher in the oPD group. Immunohistochemistry analysis was consistent with the results of mRNA analysis. CD68-positive cells were significantly increased in the oPD group. In conclusion, uremia results in NFAT5 induction, which might promote early changes of the peritoneum. Upregulation of NFAT5 in PD patients is associated with NFκB induction, potentially resulting in the recruitment of macrophages.

[New KDIGO guidelines on acute kidney injury. Practical recommendations]

The incidence of acute kidney injury (AKI) in critically ill patients is very high and is associated with an increased morbidity and mortality. In 2012 the Kidney Disease: Improving Global Outcome (KDIGO) guidelines were published in which evidence-based practical recommendations are given for the evaluation and management of patients with AKI. The first section of the KDIGO guidelines deals with the unification of earlier consensus definitions and staging criteria for AKI. The subsequent sections of the guidelines cover the prevention and treatment of AKI as well as the management of renal replacement therapy (RRT) in patients with AKI. In each section the existing evidence is discussed and a specific treatment recommendation is given. The guidelines appreciates that there is insufficient evidence for many of the recommendations. As a specific pharmacological therapy is missing, an early diagnosis, aggressive hemodynamic optimization, tight volume control, and avoidance of nephrotoxic drugs are the only interventions to prevent AKI. If renal replacement therapy is required different modalities are available to provide an effective therapy with a low rate of adverse effects.

[Treatment of acute renal failure in Germany: Analysis of current practice]

BACKGROUND AND OBJECTIVES

There are currently no reliable data on the differential use of renal replacement therapy (RRT) options for critically ill patients with acute renal failure in Germany.

PATIENTS AND METHODS

A questionnaire-based survey was delivered to 2265 German intensive care units. The questionnaire contained 19 questions regarding RRT.

RESULTS

A total of 423 German intensive care units participated in the survey. The offered modalities of RRT varied significantly: the smaller the facility, the fewer different RRT options were available. Intermittent dialysis procedures were available in only 35% of hospitals with up to 400 beds. In university hospitals, hemodynamically unstable patients were exclusively treated by continuous RRT, whereas in hospitals with up to 400 beds, intermittent RRT was also used. In addition, treatment practice was also dependent on the specialization of the treating physicians: Isolated acute renal failure was treated more often intermittently by nephrologists compared to anesthesiologists (79.7 vs. 43.3%). Nephrologists also used extracorporeal RRT more often in cardiorenal syndrome (54.3 vs. 35.8%), whereas anesthesiologists preferred them in sepsis (37.3 vs. 23.1%). The choice of anticoagulant varied as well: Hospitals with up to 400 beds offered regional citrate anticoagulation in only 50% compared to 90% of university hospitals.

CONCLUSIONS

Currently, RRT treatment in acute renal failure on German intensive care units seems to be dependent on the size, local structures, and education of the intensivists rather than patient needs. Our results demonstrate the necessity to establish cross-disciplinary standards for the treatment of acute renal failure in German intensive care units.