Optimizing Continuous Renal Replacement Therapy with Regional Citrate Anticoagulation: Insights from the ORCA Trial-A Retrospective Study on 10 Years of Practice.

(1) Background: Citrate is preferred in continuous renal replacement therapy (CRRT) for critically ill patients because it prolongs filter life and reduces bleeding risks compared to unfractionated heparin (UFH). However, regional citrate anticoagulation (RCA) can lead to acid-base disturbances, citrate accumulation, and overload. This study compares the safety and efficacy of citrate-based CRRT with UFH and no anticoagulation (NA) in acute kidney injury (AKI) patients. (2) Methods: A retrospective analysis was conducted on adult patients (≥18 years) who underwent CRRT from July 2010 to June 2021 in an intensive care unit. (3) Results: Among 829 AKI patients on CRRT: 552 received RCA, 232 UFH, and 45 NA. The RCA group had a longer filter lifespan compared to UFH and NA (56 h [IQR, 24-110] vs. 36.0 h [IQR, 17-63.5] vs. 22 h [IQR, 12-48]; all Padj < 0.001). Bleeding complications were fewer in the RCA group than in the UFH group (median 3 units [IQR, 2-7 units] vs. median 5 units [IQR, 2-12 units]; Padj < 0.001) and fewer in the NA group than in the UFH group (median 3 units [IQR, 1-5 units] vs. 5 units [IQR, 2-12 units]; Padj = 0.03). Metabolic alkalosis was more common in the RCA group (32.5%) compared to the UFH (16.2%) and NA (13.5%) groups, while metabolic acidosis persisted more in the UFH group and NA group (29.1% and 34.6%) by the end of therapy vs. the citrate group (16.8%). ICU mortality was lower in the RCA group (52.7%) compared to the UFH group (63.4%; Padj = 0.02) and NA group (77.8%; Padj = 0.003). (4) Conclusions: Citrate anticoagulation outperforms heparin-based and no anticoagulation in filter patency, potentially leading to better outcomes through improved therapy effectiveness and reduced transfusion needs. However, careful monitoring is crucial to limit potential complications attributable to its use.

Combined ultrasound of m. quadriceps and diaphragm to determine the occurrence of sarcopenia and prolonged ventilation in a COVID-19 ICU cohort: The COVID-SARCUS trial.

OBJECTIVE: The aim of this study was to determine the development of sarcopenia in a COVID-19 intensive care unit population by sequential quadriceps and diaphragm ultrasound and its relationship with hospital outcomes. METHODS: We assessed muscle thickness, cross-sectional area, fascicle length, pennation angle, and echo intensity within 48 h after intubation, at days 5 and 10 and at discharge from the intensive care unit in 30 critically ill patients with confirmed COVID-19. RESULTS: A different evolution of muscle thickness of the diaphragm and m. rectus femoris was observed; the changes between the two muscles were not correlated (Pearson's χ2 3.91, P = 0.419). The difference in muscle thickness was linked to the outcome for both m. rectus femoris and diaphragm, with the best survival seen in the group with stable muscle thickness. The greatest loss of muscle thickness occurred between days 5 and 10. The echo intensity was higher in the patients with increased muscle thickness, who also had a worse prognosis. There was a correlation between cross-sectional area on day 5 and handgrip strength (r = 0.290, P = 0.010). Only 31% of patients were able to return to their preadmission residence without any additional rehabilitation. CONCLUSIONS: Muscle atrophy and decline in muscle strength appear in the earliest stages after admission to the intensive care unit and are related to functional outcome.

Ferroptosis and pyroptosis signatures in critical COVID-19 patients.

Critical COVID-19 patients admitted to the intensive care unit (ICU) frequently suffer from severe multiple organ dysfunction with underlying widespread cell death. Ferroptosis and pyroptosis are two detrimental forms of regulated cell death that could constitute new therapeutic targets. We enrolled 120 critical COVID-19 patients in a two-center prospective cohort study to monitor systemic markers of ferroptosis, iron dyshomeostasis, pyroptosis, pneumocyte cell death and cell damage on the first three consecutive days after ICU admission. Plasma of 20 post-operative ICU patients (PO) and 39 healthy controls (HC) without organ failure served as controls. Subsets of COVID-19 patients displayed increases in individual biomarkers compared to controls. Unsupervised clustering was used to discern latent clusters of COVID-19 patients based on biomarker profiles. Pyroptosis-related interleukin-18 accompanied by high pneumocyte cell death was independently associated with higher odds at mechanical ventilation, while the subgroup with high interleuking-1 beta (but limited pneumocyte cell death) displayed reduced odds at mechanical ventilation and lower mortality hazard. Meanwhile, iron dyshomeostasis with a tendency towards higher ferroptosis marker malondialdehyde had no association with outcome, except for the small subset of patients with very high catalytic iron independently associated with reduced survival. Forty percent of patients did not have a clear signature of the cell death mechanisms studied in this cohort. Moreover, repeated moderate levels of soluble receptor of advanced glycation end products and growth differentiation factor 15 during the first three days after ICU admission are independently associated with adverse clinical outcome compared to sustained lower levels. Altogether, the data point towards distinct subgroups in this cohort of critical COVID-19 patients with different systemic signatures of pyroptosis, iron dyshomeostasis, ferroptosis or pneumocyte cell death markers that have different outcomes in ICU. The distinct groups may allow 'personalized' treatment allocation in critical COVID-19 based on systemic biomarker profiles.

Pre-admission ambient air pollution and blood soot particles predict hospitalisation outcomes in COVID-19 patients.

BACKGROUND: Air pollution exposure is one of the major risk factors for aggravation of respiratory diseases. We investigated whether exposure to air pollution and accumulated black carbon (BC) particles in blood were associated with coronavirus disease 2019 (COVID-19) disease severity, including the risk for intensive care unit (ICU) admission and duration of hospitalisation. METHODS: From May 2020 until March 2021, 328 hospitalised COVID-19 patients (29% at intensive care) were recruited from two hospitals in Belgium. Daily exposure levels (from 2016 to 2019) for particulate matter with aerodynamic diameter <2.5 µm and <10 µm (PM2.5 and PM10, respectively), nitrogen dioxide (NO2) and BC were modelled using a high-resolution spatiotemporal model. Blood BC particles (internal exposure to nano-sized particles) were quantified using pulsed laser illumination. Primary clinical parameters and outcomes included duration of hospitalisation and risk of ICU admission. RESULTS: Independent of potential confounders, an interquartile range (IQR) increase in exposure in the week before admission was associated with increased duration of hospitalisation (PM2.5 +4.13 (95% CI 0.74-7.53) days, PM10 +4.04 (95% CI 1.24-6.83) days and NO2 +4.54 (95% CI 1.53-7.54) days); similar effects were observed for long-term NO2 and BC exposure on hospitalisation duration. These effect sizes for an IQR increase in air pollution on hospitalisation duration were equivalent to the effect of a 10-year increase in age on hospitalisation duration. Furthermore, for an IQR higher blood BC load, the OR for ICU admission was 1.33 (95% CI 1.07-1.65). CONCLUSIONS: In hospitalised COVID-19 patients, higher pre-admission ambient air pollution and blood BC levels predicted adverse outcomes. Our findings imply that air pollution exposure influences COVID-19 severity and therefore the burden on medical care systems during the COVID-19 pandemic.

Regional Citrate Anticoagulation in Continuous Renal Replacement Therapy: Is Metabolic Fear the Enemy of Logic? A Systematic Review and Meta-Analysis of Randomised Controlled Trials.

BACKGROUND: Anticoagulation is recommended to maintain the patency of the circuit in continuous renal replacement therapy (CRRT). However, anticoagulation-associated complications can occur. We performed a systematic review and meta-analysis to compare the efficacy and safety of citrate anticoagulation to heparin anticoagulation in critically ill patients treated with CRRT. METHODS: Randomised controlled trials (RCTs) evaluating the safety and efficacy of citrate anticoagulation and heparin in CRRT were included. Articles not describing the incidence of metabolic and/or electrolyte disturbances induced by the anticoagulation strategy were excluded. The PubMed, Embase, and MEDLINE electronic databases were searched. The last search was performed on 18 February 2022. RESULTS: Twelve articles comprising 1592 patients met the inclusion criteria. There was no significant difference between the groups in the development of metabolic alkalosis (RR = 1.46; (95% CI (0.52-4.11); p = 0.470)) or metabolic acidosis (RR = 1.71, (95% CI (0.99-2.93); p = 0.054)). Patients in the citrate group developed hypocalcaemia more frequently (RR = 3.81; 95% CI (1.67-8.66); p = 0.001). Bleeding complications in patients randomised to the citrate group were significantly lower than those in the heparin group (RR 0.32 (95% CI (0.22-0.47); p < 0.0001)). Citrate showed a significantly longer filter lifespan of 14.52 h (95% CI (7.22-21.83); p < 0.0001), compared to heparin. There was no significant difference between the groups for 28-day mortality (RR = 1.08 (95% CI (0.89-1.31); p = 0.424) or 90-day mortality (RR 0.9 (95% CI (0.8-1.02); p = 0.110). CONCLUSION: regional citrate anticoagulation is a safe anticoagulant for critically ill patients who require CRRT, as no significant differences were found in metabolic complications between the groups. Additionally, citrate has a lower risk of bleeding and circuit loss than heparin.

Unapparent systemic effects of regional anticoagulation with citrate in continuous renal replacement therapy: a narrative review.

The use of citrate, through reversible binding of calcium, has become the preferred choice for anticoagulation in continuous renal replacement therapy in the critically ill patient. Though generally considered as very efficacious in acute kidney injury, this type of anticoagulation can cause acid-base disorders as well as citrate accumulation and overload, phenomena which have been well described. The purpose of this narrative review is to provide an overview of some other, non-anticoagulation effects of citrate chelation during its use as anticoagulant. We highlight the effects seen on the calcium balance and hormonal status, phosphate and magnesium balance, as well as oxidative stress resulting from these unapparent effects. As most of these data on these non-anticoagulation effects have been obtained in small observational studies, new and larger studies documenting both short- and long-term effects should be undertaken. Subsequent future guidelines for citrate-based continuous renal replacement therapy should take not only the metabolic but also these unapparent effects into account.

Fluid Management, Intra-Abdominal Hypertension and the Abdominal Compartment Syndrome: A Narrative Review.

BACKGROUND: General pathophysiological mechanisms regarding associations between fluid administration and intra-abdominal hypertension (IAH) are evident, but specific effects of type, amount, and timing of fluids are less clear. OBJECTIVES: This review aims to summarize current knowledge on associations between fluid administration and intra-abdominal pressure (IAP) and fluid management in patients at risk of intra-abdominal hypertension and abdominal compartment syndrome (ACS). METHODS: We performed a structured literature search from 1950 until May 2021 to identify evidence of associations between fluid management and intra-abdominal pressure not limited to any specific study or patient population. Findings were summarized based on the following information: general concepts of fluid management, physiology of fluid movement in patients with intra-abdominal hypertension, and data on associations between fluid administration and IAH. RESULTS: We identified three randomized controlled trials (RCTs), 38 prospective observational studies, 29 retrospective studies, 18 case reports in adults, two observational studies and 10 case reports in children, and three animal studies that addressed associations between fluid administration and IAH. Associations between fluid resuscitation and IAH were confirmed in most studies. Fluid resuscitation contributes to the development of IAH. However, patients with IAH receive more fluids to manage the effect of IAH on other organ systems, thereby causing a vicious cycle. Timing and approach to de-resuscitation are of utmost importance, but clear indicators to guide this decision-making process are lacking. In selected cases, only surgical decompression of the abdomen can stop deterioration and prevent further morbidity and mortality. CONCLUSIONS: Current evidence confirms an association between fluid resuscitation and secondary IAH, but optimal fluid management strategies for patients with IAH remain controversial.

A dynamic mucin mRNA signature associates with COVID-19 disease presentation and severity.

BACKGROUNDSARS-CoV-2 infection induces mucin overexpression, further promoting disease. Given that mucins are critical components of innate immunity, unraveling their expression profiles that dictate the course of disease could greatly enhance our understanding and management of COVID-19.METHODSUsing validated RT-PCR assays, we assessed mucin mRNA expression in the blood of patients with symptomatic COVID-19 compared with symptomatic patients without COVID-19 and healthy controls and correlated the data with clinical outcome parameters. Additionally, we analyzed mucin expression in mucus and lung tissue from patients with COVID-19 and investigated the effect of drugs for COVID-19 treatment on SARS-CoV-2-induced mucin expression in pulmonary epithelial cells.RESULTSWe identified a dynamic blood mucin mRNA signature that clearly distinguished patients with symptomatic COVID-19 from patients without COVID-19 based on expression of MUC1, MUC2, MUC4, MUC6, MUC13, MUC16, and MUC20 (AUCROC of 91.8%; sensitivity and specificity of 90.6% and 93.3%, respectively) and that discriminated between mild and critical COVID-19 based on the expression of MUC16, MUC20, and MUC21 (AUCROC of 89.1%; sensitivity and specificity of 90.0% and 85.7%, respectively). Differences in the transcriptional landscape of mucins in critical cases compared with mild cases identified associations with COVID-19 symptoms, respiratory support, organ failure, secondary infections, and mortality. Furthermore, we identified different mucins in the mucus and lung tissue of critically ill COVID-19 patients and showed the ability of baricitinib, tocilizumab, favipiravir, and remdesivir to suppress expression of SARS-CoV-2-induced mucins.CONCLUSIONThis multifaceted blood mucin mRNA signature showed the potential role of mucin profiling in diagnosing, estimating severity, and guiding treatment options in patients with COVID-19.FUNDINGThe Antwerp University Research and the Research Foundation Flanders COVID-19 funds.

Correction to: Chloride content of solutions used for regional citrate anticoagulation might be responsible for blunting correction of metabolic acidosis during continuous venovenous hemofiltration.

Following publication of the original article [1], we have been notified that the approved number by the Ethical Committee was given incorrectly. In the section "Methods" stated that: The Central Ethical Committee of the University Hospital approved the study protocol (B.U.N. 143201318818), this number is incorrect and should be expressed as follows: B.U.N. 143201318819."

Extracorporeal Carbon Dioxide Removal During Continuous Renal Replacement Therapy as Adjunctive Therapy.

Lung-protective ventilation targeting low tidal volumes and plateau pressures is the mainstay of therapy in patients with ARDS. This ventilation strategy limits pulmonary strain, inflammation, and injury, but it may be associated with profound hypercapnic acidosis. In such conditions, extracorporeal CO2 removal can attenuate or normalize hypercapnia and may even facilitate ultraprotective ventilation. Almost half of patients with ARDS develop renal failure. Pathophysiological cross-talk between the injured lung and kidney may aggravate global organ failure and weighs negatively on outcomes. A substantial number of patients with ARDS require continuous renal replacement therapy. Systems adapted from conventional renal replacement platforms with blood flows < 500 mL/min can achieve significant CO2 elimination. Therefore, incorporating low-flow extracorporeal CO2 removal in a continuous renal replacement therapy circuit is an attractive therapeutic option. We reviewed the relevant literature on combining extracorporeal CO2 removal with continuous renal replacement therapy.

Cytokine removal in human septic shock: Where are we and where are we going?

Although improving, the mortality from septic shock still remains high despite increased international awareness. As a consequence, much effort has focused on alternative treatment strategies in an effort to improve outcomes. The application of blood purification therapies to improve immune homeostasis has been suggested as one such method, but these approaches, such as high-volume continuous haemofiltration or cytokine and/or endotoxin removal, have enjoyed little success to date. More recently, the use of sorbent technologies has attracted much attention. These adsorbers are highly effective at removing inflammatory mediators, in particular, cytokines, from the bloodstream. This narrative review is the executive summary of meetings held throughout the 6th International Fluid Academy Days in Antwerp, Belgium (Nov 23-25, 2017), focusing on the current understanding regarding the use of such adsorbers in humans with septic shock. We followed a modified Delphi approach involving a combination of evidence appraisal together with expert opinion in order to achieve recommendations for practice and, importantly, future research.

Do Statins Induce or Protect from Acute Kidney Injury and Chronic Kidney Disease: An Update Review in 2018.

Statins essentially are cholesterol-lowering drugs that are extensively prescribed for primary and secondary prevention of cardiovascular disease. Compelling evidence suggests that the beneficial effects of statins may not only be due to its ability to control cholesterol levels but also due to a pleiotropic cholesterol-independent anti-inflammatory, antioxidant, endothelial-protective and plaque-stabilizing activity. Along this line, statins may also exert acute and long-term effects on renal function. We present a narrative literature review that summarizes arguments in favor of or against the preventive and/or therapeutic use of statins in kidney-related diseases or complications. We also highlight the ongoing controversy regarding statin therapy in chronic and end-stage kidney disease.

Applying pharmacokinetic/pharmacodynamic principles for optimizing antimicrobial therapy during continuous renal replacement therapy

Continuous renal replacement therapy (CRRT) is progressively supplanting intermittent haemodialysis (IHD) in critically ill patients. Although CRRT indeed offers more appropriate haemodynamic, fluid, and metabolic stability, concern is rising about its impact on concomitant drugs and, in particular, antimicrobial treatment. Antimicrobial dose recommendations have been elaborated to avoid drug accumulation and toxicity in patients undergoing IHD. However, these dosing regimens have resulted in significant underdosing in patients undergoing CRRT, thereby increasing the risk of treatment failure and development of resistance. Applying pharmacokinetic/pharmacodynamic (PK/PD) principles may aid one to obtain more adequate antimicrobial therapy during CRRT. Much progress has been made in recent years resulting in relevant changes in particular antimicrobial therapies. In this review, we discuss antimicrobials that are frequently used in an intensive care setting. Drugs are divided according to their PK/PD characteristics and, wherever possible, dose recommendations during CRRT are provided. Of course, while therapeutic drug monitoring remains the best way to cope with PK/PD variability within a critically ill CRRT population, its bedside use is actually limited to some specific antibiotics.

Statins and the Kidney: Friend or Foe?

Statins essentially are cholesterol-lowering drugs that are extensively prescribed for primary and secondary prevention of cardiovascular disease. Compelling evidence suggests that the beneficial effects of statins may not only be due to controlling cholesterol levels but also due to a pleiotropic cholesterol-independent anti-inflammatory, antioxidant, endothelial-protective and plaque-stabilizing activity. Along this line, statins may also exert acute and long-term effects on renal function. We present a narrative literature review that summarizes arguments in favour or against the preventive and/or therapeutic use of statins in kidney-related diseases or complications. We also highlight the ongoing controversy regarding statin therapy in chronic and end-stage kidney disease.

Biomarkers in critical illness: have we made progress?

Biomarkers have emerged as exemplary key players in translational medicine. Many have been assessed for timely recognition, early treatment, and adequate follow-up for a variety of pathologies. Biomarker sensitivity has improved considerably over the last years but specificity remains poor, in particular when two "marker-sensitive" conditions overlap in one patient. Biomarker research holds an enormous potential for diagnostic and prognostic purposes in postoperative and critically ill patients who present varying degrees of inflammation, infection, and concomitant (sub)acute organ dysfunction or failure. Despite a remarkable progress in development and testing, biomarkers are not yet ready for routine use at the bedside.