Advanced organ support (ADVOS) in the critically ill: first clinical experience in patients with multiple organ failure

Background

Prevalence of multiple organ failure (MOF) in critically ill patients is increasing and associated mortality remains high. Extracorporeal organ support is a cornerstone in the management of MOF. We report data of an advanced hemodialysis system based on albumin dialysis (ADVOS multi device) that can regulate acid–base balance in addition to the established properties of renal replacement therapy and albumin dialysis systems in critically ill patients with MOF.

Methods

34 critically ill patients with MOF received 102 ADVOS treatment sessions in the Department of Intensive Care Medicine of the University Medical Center Hamburg-Eppendorf. Markers of metabolic detoxification and acid–base regulation were collected and blood gas analyses were performed. A subgroup analyses were performed in patients with severe acidemia (pH < 7.2).

Results

Median number of treatment sessions was 2 (range 1–9) per patient. Median duration of treatment was 17.5 (IQR 11–23) hours per session. Treatment with the ADVOS multi-albumin dialysis device caused a significant decrease in bilirubin levels, serum creatinine, BUN and ammonia levels. The relative elimination rate of bilirubin was concentration dependent. Furthermore, a significant improvement in blood pH, HCO₃⁻ and PaCO₂, was achieved during ADVOS treatment including six patients that suffered from severe metabolic acidosis refractory to continuous renal replacement therapy. Delta pH, HCO₃⁻ and PaCO₂ were significantly affected by the ADVOS blood flow rate and pH settings. This improvement in the clinical course during ADVOS treatments allowed a reduction in norepinephrine during ADVOS therapy. Treatments were well tolerated. Mortality rates were 50% and 62% for 28 and 90 days, respectively.

Conclusions

In this case series in patients with MOF, ADVOS was able to eliminate water-soluble and albumin-bound substances. Furthermore, the device corrected severe metabolic and respiratory acid–base disequilibrium. No major adverse events associated with the ADVOS treatments were observed.

Extracorporeal Blood Purification and Organ Support in the Critically Ill Patient during COVID-19 Pandemic: Expert Review and Recommendation

Critically ill COVID-19 patients are generally admitted to the ICU for respiratory insufficiency which can evolve into a multiple-organ dysfunction syndrome requiring extracorporeal organ support. Ongoing advances in technology and science and progress in information technology support the development of integrated multi-organ support platforms for personalized treatment according to the changing needs of the patient. Based on pathophysiological derangements observed in COVID-19 patients, a rationale emerges for sequential extracorporeal therapies designed to remove inflammatory mediators and support different organ systems. In the absence of vaccines or direct therapy for COVID-19, extracorporeal therapies could represent an option to prevent organ failure and improve survival. The enormous demand in care for COVID-19 patients requires an immediate response from the scientific community. Thus, a detailed review of the available technology is provided by experts followed by a series of recommendation based on current experience and opinions, while waiting for generation of robust evidence from trials.

Options in extracorporeal support of multiple organ failure

Multiorgan failure is among the most frequent reasons of death in critically ill patients. Based on extensive and long-term use of renal replacement therapy, extracorporeal organ support became available for other organ failures. Initially, most of these techniques (e.g. extracorporeal membrane oxygenation, extracorporeal CO₂ removal [ECCO2R] and extracorporeal liver support) were used as stand-alone single organ support systems. Considering multiple interactions between native organs (“crosstalk”), combined or integrated extracorporeal organ support (ECOS) devices are intriguing. The concept of multiple organ support therapy (MOST) providing simultaneous and combined support for different failing organs was described more than 15 years ago by Ronco and Bellomo. This concept also implicates overcoming the “compartmentalized” approach provided by different single organ specialized professionals by a multidisciplinary and multiprofessional strategy. The idea of MOST is supported by the failure of several recent studies on single organ support including liver and lung support. Improvement of outcome by ECOS necessarily depends on optimized patient selection, integrated organ support and limitation of its side effects. This implicates challenges for engineers, industry and healthcare professionals. From a technical viewpoint, modular combination of pre-existing technologies such as renal replacement, albumin-dialysis, ECCO2R and potentially cytokine elimination can be considered as a first step. While this allows for stepwise and individual combination of standard organ support facilities, it carries the disadvantage of large extracorporeal blood volume and surfaces as well as additive costs. The more intriguing next step is an integrated platform providing the capacity of multiple organ support within one device. (This article is freely available.)

Respiratory and metabolic acidosis correction with the ADVanced Organ Support system

Background

The lung, the kidney, and the liver are major regulators of acid-base balance. Acidosis due to the dysfunction of one or more organs can increase mortality, especially in critically ill patients. Supporting compensation by increasing ventilation or infusing bicarbonate is often ineffective. Therefore, direct removal of acid may represent a novel therapeutic approach. This can be achieved with the ADVanced Organ Support (ADVOS) system, an enhanced renal support therapy based on albumin dialysis. Here, we demonstrate proof of concept for this technology.

Methods

An ex vivo model of either hypercapnic (i.e., continuous CO₂ supply) or lactic acidosis (i.e., lactic acid infusion) using porcine blood was subjected to hemodialysis with ADVOS. A variety of operational parameters including blood and dialysate flows, different dialysate pH settings, and acid and base concentrate compositions were tested. Comparisons with standard continuous veno-venous hemofiltration (CVVH) using high bicarbonate substitution fluid and continuous veno-venous hemodialysis (CVVHD) were also performed.

Results

Sixty-one milliliters per minute (2.7 mmol/min) of CO₂ was removed using a blood flow of 400 ml/min and a dialysate pH of 10 without altering blood pCO₂ and HCO₃⁻ (36 mmHg and 20 mmol/l, respectively). Up to 142 ml/min (6.3 mmol/min) of CO₂ was eliminated if elevated pCO₂ (117 mmHg) and HCO₃⁻ (63 mmol/l) were allowed. During continuous lactic acid infusion, an acid load of up to 3 mmol/min was compensated. When acidosis was triggered, ADVOS multi normalized pH and bicarbonate levels within 1 h, while neither CVVH nor CVVHD could. The major determinants to correct blood pH were blood flow, dialysate composition, and initial acid-base status.

Conclusions

In conclusion, ADVOS was able to remove more than 50% of the amount of CO₂ typically produced by an adult human. Blood pH was maintained stable within the physiological range through compensation of a metabolic acid load by albumin dialysate. These in vitro results will require confirmation in patients.

From Multiple Organ Support Therapy to Extracorporeal Organ Support in Critically Ill Patients

Critically ill patients developing severe forms multiple organ dysfunction syndrome (MODS) may not be adequately supported by pharmacologic management. In these complex cases, a single form of extracorporeal organ support (ECOS) may be required, but multiple organ support therapy (MOST) is currently seen as a feasible approach. Severe renal dysfunction is a typical syndrome requiring renal replacement therapy (RRT) in the context of MODS. After more than a decade of RRT application in various intensive care settings, ECOS are not anymore seen as extraordinary or particularly aggressive techniques in MODS patients. Nowadays, a significant increase in the use of extracorporeal membrane oxygenation and extracorporeal carbon dioxide removal is occurring. When renal and cardio-pulmonary ECOS are used together, a multidisciplinary approach is necessary to minimize negative interactions and unwanted adverse effects. In this editorial, we focus on the organ crosstalk between the native and artificial organs, including the advantages and disadvantages of organ support on multiorgan function. Much of current experience on MOST has been gained upon RRT connected to other organ support therapies. Overall, available literature has not definitely established the ideal timing of these interventions, and whether early implementation impacts organ recovery and optimizes resource utilization is still a matter of open debate: it is possible that future research will be devoted to identify patient groups that may benefit from short- and long-term multiple organ support. Video Journal Club "Cappuccino with Claudio Ronco" at  https://www.karger.com/Journal/ArticleNews/490694?sponsor=52.

Evaluation of an ADVanced Organ Support (ADVOS) system in a two-hit porcine model of liver failure plus endotoxemia

Background

Novel extracorporeal procedures are constantly being developed and evaluated for use in patients with sepsis. Preclinical evaluation of such procedures usually requires testing in large animal models. In the present work, the safety and efficacy of a recently developed ADVanced Organ Support (ADVOS) system in a newly developed large animal two-hit model of liver failure combined with endotoxemia were tested.

Methods

After establishing the model in more than 50 animals, a randomized study was performed. An inflammatory cholestatic liver injury was initially provoked in pigs. Three days after surgery, endotoxin was gradually administered during 7½ h. Animals were randomized to receive standard medical treatment either with (ADVOS group, n = 5) or without ADVOS (control group, n = 5). The ADVOS treatment was started 2½ h after endotoxemia and continued for 7 h. Survival, cardiovascular, respiratory, renal, liver, coagulation, and cerebral parameters were analyzed.

Results

Three days after surgery, cholestatic injury resulted in hyperbilirubinemia [5.0 mg/dl (IQR 4.3–5.9 mg/dl)], hyperammonemia [292 μg/dl (IQR 291–296 μg/dl)], leukocytosis [20.2 10³/μl (IQR 17.7–21.8 10³/μl)], and hyperfibrinogenemia [713 mg/dl (IQR 654–803 mg/dl)]. After endotoxemia, the ADVOS procedure stabilized cardiovascular, respiratory, and renal parameters and eliminated surrogate markers as bilirubin [2.3 (IQR 2.3–3.0) vs. 5.5 (IQR 4.6–5.6) mg/dl, p = 0.001] and creatinine [1.4 (IQR 1.1–1.7) vs. 2.3 (IQR 2.1–3.1) mg/dl, p = 0.01]. Mortality: All animals in the ADVOS group survived, while all animals in the control group expired during the 10-h observation period (p = 0.002). No adverse events related to the procedure were observed.

Conclusions

The ADVOS procedure showed a promising safety and efficacy profile and improved survival in a sepsis-like animal model with dysfunction of multiple organs. An amelioration of major organ functions (heart and lung) combined with removal of markers for kidney and liver function was observed.

Electronic supplementary material

The online version of this article (doi:10.1186/s40635-017-0144-3) contains supplementary material, which is available to authorized users.

A New Application for Albumin Dialysis in Extracorporeal Organ Support: Characterization of a Putative Interaction Between Human Albumin and Proinflammatory Cytokines IL-6 and TNFα

Albumin dialysis in extracorporeal organ support is often performed in the treatment of liver failure as it facilitates the removal of toxic components from the blood. Here, we describe a possible effect of albumin dialysis on proinflammatory cytokine levels in vitro. Initially, albumin samples were incubated with different amounts of cytokines and analyzed by enzyme-linked immunosorbent assay (ELISA). Analysis of interleukin 6 (IL-6) and tumor necrosis factor alpha (TNFα) levels indicated that increased concentrations of albumin reduce the measureable amount of the respective cytokines. This led to the hypothesis that the used proinflammatory cytokines may interact with albumin. Size exclusion chromatography of albumin spiked with cytokines was carried out using high-performance liquid chromatography analysis. The corresponding fractions were evaluated by immunoblotting. We detected albumin and cytokines in the same fractions indicating an interaction of the small-sized cytokines IL-6 and TNFα with the larger-sized albumin. Finally, a two-compartment albumin dialysis in vitro model was used to analyze the effect of albumin on proinflammatory cytokines in the recirculation circuit during 6-h treatment. These in vitro albumin dialysis experiments indicated a significant decrease of IL-6, but not of TNFα, when albumin was added to the dialysate solution. Taken together, we were able to show a putative in vitro interaction of human albumin with the proinflammatory cytokine IL-6, but with less evidence for TNFα, and demonstrated an additional application for albumin dialysis in liver support therapy where IL-6 removal might be indicated.