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There is currently a clear biologic rationale for blood purification used in sepsis. Immunomodulation and organ support play important roles in the application of blood purification. Conventional continuous venovenous hemofiltration and hemodialysis have been shown not to be effective in sepsis in the absence of concomitant acute renal failure. Plasma therapies, high-volume hemofiltration, hemadsorption, or combinations of these therapies appear promising. However many questions still remain unanswered. Current technologies still remain inadequate for the removal of middle-molecular-weight substances, and the current practice worldwide is extremely variable. Moreover, there is lack of large-scale randomized clinical trials. Recently, new developing technologies may enhance the clinical results of current RRT strategies, including high-porosity of membranes to improve middle molecular clearance. Finally, multicenter randomized controlled trials are needed to test these promising blood purification technologies.

The issue of acute dialysis dose prescription has undergone significant revision in the last 10 years. The previous idea that critically ill patients' survival was proportional to delivered dialysis being the highest with the highest dose has been downplayed. The best evidence supports a continuous renal replacement therapy dose of at least 25 mL/kg/hr of effluent flow rate, for venovenous hemofiltration, hemodialysis, or hemodiafiltration. However, if standard dose prescription may be recommended at the start of an acute dialytic treatment, strict control of delivered dose is recommended for adequate delivery of the prescribed dose. Furthermore, prescription and delivery should be reassessed frequently to meet the patients' needs, tailoring the removal of solutes to the complex and rapidly changing metabolism of different patients.

Acute kidney injury (AKI) is a common problem with adverse outcomes. More timely diagnosis would allow for earlier interventions and could improve patient outcomes. Due to the inherent limitation of serum creatinine, numerous novel biomarkers have been discovered for early identification of AKI. In addition to facilitating earlier diagnosis, these biomarkers have been demonstrated to play roles in risk stratification, early intervention, and prognosis. However, the diagnostic and prognostic predictive power of these biomarkers is variable, and only few biomarkers are in widespread clinical use. A panel of biomarkers or integration with clinical judgment may improve their performance.

The overall incidence of acute kidney injury (AKI) in the USA is estimated to be about 7/1000 population [1]. Older adults and children are disproportionately affected in a bimodal distribution mirroring the incidence of sepsis [2], the leading cause of AKI [3–6]. Even mild forms of AKI are associated with increased risk of hospital mortality [6, 7], and AKI may result in chronic kidney disease and life-long morbidity, shortened survival and increased costs [8]. Moreover, severity of AKI varies by etiology and sepsis-associated AKI tends to be most severe. For example, KDIGO stage 3 occurs in 20% of patients with septic shock [9]. Once acquired, the consequences of AKI are also unequally distributed. Approximately one third of patients exhibit no reversal of renal dysfunction within the first few days of AKI. Roughly 25% will never recover, and experience a fivefold increase in mortality over the ensuing year [10]. Even among patients with sepsis-associated AKI, outcomes are heterogeneous and different mechanisms may be involved [11]—indeed, no fewer than six have been proposed [12]. Renal endothelial pathology is prevalent in experimental models of sepsis [12, 13]. Endothelial injury can reduce microcirculatory flow leading to perfusion abnormalities and interstitial infiltration of inflammatory cells [13]. However, the reasons some patients exhibit these pathologic features while others do not are obscure.

Acute kidney injury (formerly known as acute renal failure) is a syndrome characterised by the rapid loss of the kidney's excretory function and is typically diagnosed by the accumulation of end products of nitrogen metabolism (urea and creatinine) or decreased urine output, or both. It is the clinical manifestation of several disorders that affect the kidney acutely. Acute kidney injury is common in hospital patients and very common in critically ill patients. In these patients, it is most often secondary to extrarenal events. How such events cause acute kidney injury is controversial. No specific therapies have emerged that can attenuate acute kidney injury or expedite recovery; thus, treatment is supportive. New diagnostic techniques (eg, renal biomarkers) might help with early diagnosis. Patients are given renal replacement therapy if acute kidney injury is severe and biochemical or volume-related, or if uraemic-toxaemia-related complications are of concern. If patients survive their illness and do not have premorbid chronic kidney disease, they typically recover to dialysis independence. However, evidence suggests that patients who have had acute kidney injury are at increased risk of subsequent chronic kidney disease.

Background: Cardiac surgery is a leading cause of acute kidney injury (AKI). Such AKI patients may develop progressive chronic kidney disease (CKD). Others, who appear to have sustained no permanent loss of function (normal serum creatinine), may still lose renal functional reserve (RFR). Methods: We extended the follow-up in the observational 'Preoperative RFR Predicts Risk of AKI after Cardiac Surgery' study from hospital discharge to 3 months after surgery for 86 (78.2%) patients with normal baseline estimated glomerular filtration rate (eGFR), and re-measured RFR with a high oral protein load. The primary study endpoint was change in RFR. Study registration at clinicaltrials.gov Identifier: NCT03092947, ISRCTN Registry: ISRCTN16109759. Results: At 3 months, three patients developed new CKD. All remaining patients continued to have a normal eGFR (93.3 ± 15.1 mL/min/1.73 m2). However, when stratified by post-operative AKI and cell cycle arrest (CCA) biomarkers, AKI patients displayed a significant decrease in RFR {from 14.4 [interquartile range (IQR) 9.5 - 24.3] to 9.1 (IQR 7.1 - 12.5) mL/min/1.73 m2; P

Context: Remote ischemic preconditioning (RIPC), whereby providing brief episodes of ischemia and reperfusion to an organ site to provide protection to a distant target organ, has great implications for critical care nephrology. This chapter summarizes the hypothesized mechanisms, clinical utility, and future directions for RIPC. Evidence Acquisition: PubMed was searched for studies reporting the effect of RIPC on acute kidney injury (AKI), contrast-induced AKI, and kidney transplantation. Additional citations were found by reviewing the biographies of relevant articles. Results: RIPC has been explored as a renoprotective strategy for AKI, contrast-induced AKI, and kidney transplantation. The differential beneficial effect of RIPC when comparing investigations may be due to differences in study protocols, patient populations, and medications exposure. Conclusions: Recent investigations suggest that studies exploring the use of biomarkers as a method to predict which patients may ultimately benefit from the use of RIPC are needed.

Specific treatments for acute kidney injury (AKI) are still not available, so prevention of AKI is fundamental to reduce the impact of AKI in critically ill patients. This chapter reviews the recent scientific literature and describes the most important nonpharmacologic approaches in preventing AKI, focusing on monitoring and optimizing hemodynamic status and minimizing nephrotoxic exposures. Critically ill patients should benefit from the maintenance of adequate volume status, but fluid overload is associated with worse outcomes and should be avoided; however, protocolized-based resuscitation is not superior to the standard care in this setting. Use of crystalloids rather than colloids is preferred and suggested. Although data from randomized controlled trials did not describe the superiority of buffered solutions, chloride-rich solutions should be avoided for patients at high risk for hyperchloremic metabolic acidosis. The persistence of hypotension after optimization of volume status should be avoided; a mean arterial pressure of 65 mm Hg or greater is required in patients with distributive shock. In patients at high risk for AKI, nephrotoxic exposure should be minimized. Low- and iso-osmolar contrast agents should be preferred and used in the lowest volume consistent with a diagnostic result; volume expansion and adequate monitoring of renal function postprocedure should be performed. Other nephrotoxic drugs, such as amphotericin B and aminoglycosides, should be used only when necessary and with caution. The maintenance of adequate hemodynamic and volume status and the minimization of nephrotoxic exposures are the most effective nonpharmacologic strategies to prevent AKI.

Background Remote ischaemic preconditioning (RIPC) consists of repeated cycles of limb ischaemia and reperfusion, which may reduce perioperative myocardial ischaemic damage and kidney injury. We hypothesised that RIPC may be beneficial by attenuating the systemic inflammatory response. We investigated whether RIPC affects the response in humans to bacterial endotoxin (lipopolysaccharide [LPS]) by measuring plasma cytokines and renal cell-cycle arrest mediators, which reflect renal tubular stress. Methods Healthy male volunteers were randomised to receive either daily RIPC for 6 consecutive days (RIPCmultiple, n=10) plus RIPC during the 40 min preceding i.v. LPS (2 ng kg−1), RIPC only during the 40 min before LPS (RIPCsingle, n=10), or no RIPC preceding LPS (control, n=10). As a surrogate marker of renal tubular stress, the product of urinary concentrations of two cell-cycle arrest markers was calculated (tissue inhibitor of metalloproteinases-2 [TIMP2]*insulin-like growth factor binding protein-7 [IGFBP7]). Data are presented as median (inter-quartile range). Results In both RIPC groups, RIPC alone increased [TIMP2]*[IGFBP7]. LPS administration resulted in fever, flu-like symptoms, and haemodynamic alterations. Plasma cytokine concentrations increased profoundly during endotoxaemia (control group: tumor necrosis factor alpha [TNF-α] from 14 [9–16] pg ml−1 at baseline to 480 [284–709] pg ml−1 at 1.5 h after LPS; interleukin-6 [IL-6] from 4 [4–4] pg ml−1 at baseline to 659 [505–1018] pg ml−1 at 2 h after LPS). LPS administration also increased urinary [TIMP2[*[IGFBP7]. RIPC had no effect on LPS-induced cytokine release or [TIMP2]*[IGFBP7]. Conclusions RIPC neither modulated systemic cytokine release nor attenuated inflammation-induced tubular stress after LPS. However, RIPC alone induced renal markers of cell-cycle arrest. Clinical trial registration NCT 02602977.

Sepsis associated acute kidney injury (S-AKI) significantly worsens patient prognosis and recent evidence suggests that the injury process begins early and may be sustained by therapies used to treat the sepsis (e.g. fluids resuscitation, antibiotics). While efforts to develop less-injurious treatments are making progress, some degree of secondary injury is to be expected. So too is the inevitable nature of organ injury, which is often present at the time the patient seeks medical attention. We recently found most patients presenting with septic shock and developing AKI had evidence of kidney damage at the time of, or within 24 hours of their admission. In such patients, prevention is not a viable option as injury has already occurred by the time of presentation. Since S-AKI patients are at increased risk of developing chronic kidney disease, a fundamental target for interventions in sepsis-associated AKI (S-AKI) is to prevent fibrosis (maladaptive repair) while stimulating regeneration (proliferation of viable epithelial cells). Using a pathway-agnostic, proliferation-based phenotypic assay, we discovered phenylthiobutanoic acid (PTBA), a small molecule histone deacetylase inhibitor, that enhances renal recovery and reduces fibrosis in both zebrafish and mouse models of AKI.

sn2-15-Hydroperoxy-eicasotetraenoyl-phosphatidylethanolamines (sn2-15-HpETE-PE) generated by mammalian 15-lipoxygenase/phosphatidylethanolamine binding protein-1 (15-LO/PEBP1) complex is a death signal in a recently identified type of programmed cell demise, ferroptosis. How the enzymatic complex selects sn2-ETE-PE as the substrate among 1 of similar to 100 total oxidizable membrane PUFA phospholipids is a central, yet unresolved question. To unearth the highly selective and specific mechanisms of catalytic competence, we used a combination of redox lipidomics, mutational and computational structural analysis to show they stem from (i) reactivity toward readily accessible hexagonally organized membrane sn2-ETE-PEs, (ii) relative preponderance of sn2-ETE-PE species vs other sn2-ETE-PLs, and (iii) allosteric modification of the enzyme in the complex with PEBP1. This emphasizes the role of enzymatic vs random stochastic free radical reactions in ferroptotic death signaling.

Objective To assess the impact of remote ischemic peri-conditioning (RIPC) during inter-facility air medical transport of ST-segment elevation myocardial infarction (STEMI) patients on the incidence of acute kidney injury (AKI) following primary percutaneous coronary intervention (pPCI). Background STEMI patients who receive pPCI have an increased risk of AKI for which there is no well-defined prophylactic therapy in the setting of emergent pPCI. Methods Using the ACTION Registry-GWTG, we evaluated the impact of RIPC applied during inter-facility helicopter transport of STEMI patients from non-PCI capable hospitals to 2 PCI-hospitals in the United States between March, 2013 and September, 2015 on the incidence of AKI following pPCI. AKI was defined as ≥0.3 mg/dL increase in creatinine within 48–72 hours after pPCI. Results Patients who received RIPC (n = 127), compared to those who did not (n = 92), were less likely to have AKI (11 of 127 patients [8.7%] vs. 17 of 92 patients [18.5%]; adjusted odds ratio = 0.32, 95% CI 0.12–0.85, P = 0.023) and all-cause in-hospital mortality (2 of 127 patients [1.6%] vs. 7 of 92 patients [7.6%]; adjusted odds ratio = 0.14, 95% CI 0.02–0.86, P = 0.034) after adjusting for socio-demographic and clinical characteristics. There was no difference in hospital length of stay (3 days [interquartile range, 2–4] vs. 3 days [interquartile range, 2–5], P = 0.357) between the 2 groups. Conclusion RIPC applied during inter-facility helicopter transport of STEMI patients for pPCI is associated with lower incidence of AKI and in-hospital mortality. The use of RIPC for renal protection in STEMI patients warrants further in depth investigation.

To assess the reversibility of acute kidney injury-induced neutrophil dysfunction and to identify involved mechanisms.Controlled laboratory experiment and prospective observational clinical study.University laboratory and hospital.C57BL/6 wild-type mice.Patients with septic shock with or without acute kidney injury.Murine acute kidney injury was induced by intraperitoneal injections of folic acid (nephrotoxic acute kidney injury) or by IM injections of glycerol (rhabdomyolysis-induced acute kidney injury). After 24 hours, we incubated isolated neutrophils for 3 hours in normal mouse serum or minimum essential medium buffer. We further studied the effects of plasma samples from 13 patients with septic shock (with or without severe acute kidney injury) on neutrophilic-differentiated NB4 cells.Experimental acute kidney injury significantly inhibited neutrophil migration and intracellular actin polymerization. Plasma levels of resistin, a proinflammatory cytokine and uremic toxin, were significantly elevated during both forms of acute kidney injury. Incubation in serum or minimum essential medium buffer restored normal neutrophil function. Resistin by itself was able to induce acute kidney injury-like neutrophil dysfunction in vitro. Plasma resistin was significantly higher in patients with septic shock with acute kidney injury compared with patients with septic shock alone. Compared with plasma from patients with septic shock, plasma from patients with septic shock and acute kidney injury inhibited neutrophilic-differentiated NB4 cell migration. Even after 4 days of renal replacement therapy, plasma from patients with septic shock plus acute kidney injury still showed elevated resistin levels and inhibited neutrophilic-differentiated NB4 cell migration. Resistin inhibited neutrophilic-differentiated NB4 cell migration and intracellular actin polymerization at concentrations seen during acute kidney injury, but not at normal physiologic concentrations.Acute kidney injury-induced neutrophil dysfunction is reversible in vitro. However, standard renal replacement therapy does not correct this defect in patients with septic shock and acute kidney injury. Resistin is greatly elevated during acute kidney injury, even with ongoing renal replacement therapy, and is sufficient to cause acute kidney injury-like neutrophil dysfunction by itself.

Background The NEPROCHECK test (Astute Medical, San Diego, CA, USA) combines urinary tissue inhibitor of metalloproteinases-2 (TIMP-2) and insulin-like growth factor binding protein 7 (IGFBP7) to identify patients at high risk for acute kidney injury (AKI). In a US Food and Drug Administration registration trial (NCT01573962), AKI was determined by a three-member clinical adjudication committee. The objectives were to examine agreement among adjudicators as well as between adjudicators and consensus criteria for AKI and to determine the relationship of biomarker concentrations and adjudicator agreement. Methods Subjects were classified as AKI 3/3, 2/3, 1/3 or 0/3 according to the proportion of adjudicators classifying the case as AKI. Subjects were classified as Kidney Disease: Improving Global Outcomes (KDIGO) AKI(+) when stage 2 or 3 AKI criteria were met. Results Concordance between adjudicators and between adjudicators and KDIGO criteria were lower for AKI than non-AKI subjects [78.9 versus 97.3% (P < 0.001) and 91.5 versus 97.9% (P = 0.01)]. Subjects who were AKI 3/3 or 2/3 but KDIGO AKI(−) had higher median [TIMP-2]•[IGFBP7] compared with those who were AKI-1/3 or 0/3 but KDIGO AKI(+) {2.78 [interquartile range (IQR) 2.33–3.56] versus 0.52 [IQR 0.26–1.64]; P = 0.008}. [TIMP-2]•[IGFBP7] levels were highest in patients with AKI 3/3 and lowest in AKI 0/3, whereas AKI 2/3 and 1/3 exhibited intermediate values. Conclusions In this analysis, urine [TIMP-2]•[IGFBP7] levels correlated to clinically adjudicated AKI better than to KDIGO criteria. Furthermore, in difficult cases where adjudicators overruled KDIGO criteria, the biomarker test discriminated well. This study highlights the importance of clinical adjudication of AKI for biomarker studies and lends further support for the value of urine [TIMP-2]•[IGFBP7].

Background Identification of acute kidney injury (AKI) can be challenging in patients with underlying chronic disease, and biomarkers often perform poorly in this population. In this study we examined the performance characteristics of the novel biomarker panel of urinary tissue inhibitor of metalloproteinases-2 (TIMP2) and insulin-like growth factor-binding protein 7 ([IGFBP7]) in patients with a variety of comorbid conditions. Methods We analyzed data from two multicenter studies of critically ill patients in which [TIMP2]•[IGFBP7] was validated for prediction of Kidney Disease: Improving Global Outcomes (KDIGO) Stage 2 or 3 AKI within 12 h. We constructed receiver operating characteristic (ROC) curves for AKI prediction both overall and by comorbid conditions common among patients with AKI, including diabetes mellitus, congestive heart failure (CHF) and chronic kidney disease (CKD). Results In the overall cohort of 1131 patients, 139 (12.3%) developed KDIGO Stage 2 or 3 AKI. [TIMP2]•[IGFBP7] was significantly higher in AKI versus non-AKI patients, both overall and within each comorbidity subgroup. The AUC for [TIMP2]•[IGFBP7] in predicting AKI was 0.81 overall. Higher AUC was noted in patients with versus without CHF (0.89 versus 0.79; P = 0.026) and CKD (0.91 versus 0.80; P = 0.024). Conclusions We observed no significant impairment in the performance of cell cycle arrest biomarkers due to the presence of chronic comorbid conditions.

Background Acute kidney injury (AKI) is associated with increased mortality, morbidity, hospital length of stay, and costs. A quantitative urine test is available to assess the risk of developing AKI by measuring the concentrations of two protein biomarkers, TIMP-2 and IGFBP-7. The NephroCheck Test combines these concentrations into an AKIRisk Score. The purpose of this study is to characterize the analytical performance characteristics of the AKIRisk Score. Methods Linearity and analytical sensitivity were evaluated by following Clinical Laboratory Standards Institute (CLSI) EP06-A and EP17-A, respectively. Precision was evaluated by testing clinical samples and examining the repeatability of test results. Potential interference was evaluated for endogenous and exogenous substances. Sample stability was examined at room temperature and at 2–8 °C, as well as the effect of sample centrifugation temperature on test results. Results The AKIRisk Score exhibits approximately 10% coefficient of variation (CV) at the recommended cutoff value of 0.3 and the limit of quantitation (LoQ) was 0.002. Only albumin, bilirubin (conjugated), and methylene blue interfered with test results, at concentrations exceeding 1250 mg/L, 72 mg/L, and 0.49 mg/L, respectively. AKIRisk Score results were stable for 6 h at room temperature, 24 h refrigerated, and not impacted by sample centrifugation temperature. Conclusions Our studies demonstrate that the AKIRisk Score has robust analytical performance, good precision, minimal analytical interference, acceptable sensitivity, and excellent sample stability.

Acute kidney injury is a common complication in critically ill patients and is associated with increased morbidity and mortality. Sepsis, major surgery, and nephrotoxic drugs are the most common causes of acute kidney injury. There is currently no effective strategy available to prevent or treat acute kidney injury. Therefore, novel treatment regimens are required to decrease acute kidney injury prevalence and to improve clinical outcomes. Remote ischemic preconditioning, triggered by brief episodes of ischemia and reperfusion applied in distant tissues or organs before the injury of the target organ, attempts to invoke adaptive responses that protect against acute kidney injury. We sought to evaluate the clinical evidence for remote ischemic preconditioning as a potential strategy to protect the kidney and to review the underlying mechanisms in light of recent studies.We searched PubMed for studies reporting the effect of remote ischemic preconditioning on kidney function in surgical patients (search terms: "remote ischemic preconditioning," "kidney function," and "surgery"). We also reviewed bibliographies of relevant articles to identify additional citations.Published studies, consisting of randomized controlled trials, are reviewed.The authors used consensus to summarize the evidence behind the use of remote ischemic preconditioning.In addition, the authors suggest patient populations and clinical scenarios in which remote ischemic preconditioning might be best applied.Several experimental and clinical studies have shown tissue-protective effects of remote ischemic preconditioning in various target organs, including the kidneys. Remote ischemic preconditioning may offer a novel, noninvasive, and inexpensive treatment strategy for decreasing acute kidney injury prevalence in high-risk patients. Although many new studies have further advanced our knowledge in this area, the appropriate intensity of remote ischemic preconditioning, its mechanisms of action, and the role of biomarkers for patient selection and monitoring are still unknown.

Organ dysfunction induced by sepsis has been consistently associated with worse outcome and death. Regardless of the organ compromised, epithelial dysfunction is present throughout the body, affecting those organs that contain epithelia like the skin, lungs, liver, gut, and kidneys. Despite their obvious differences, sepsis seems to alter common features of all epithelia, such as barrier function and vectorial ion transport. Such alterations in the lung, the gut, and the kidney have direct implications that may explain the profound organ functional impairments in the absence of overt cell death. Epithelial injury in this context is not only an explanatory real pathophysiologic event, but also represents a source of biomarkers that have been explored to identify organ compromise earlier, predict outcome, and even to test novel therapeutic interventions such as blood purification. However, this remains largely experimental, and despite promising results, work is still required to better understand the response of the epithelial cells to sepsis, to define their role in adaptation to insults, to comprehend the interorgan cross-talk that occurs in these circumstances, and to exploit these aspects in pursuit of targeted therapies like blood purification, which may improve outcome for these patients in the future.

Mitochondria are an essential part of the cellular infrastructure, being the primary site for high-energy adenosine triphosphate production through oxidative phosphorylation. Clearly, in severe systemic inflammatory states, like sepsis, cellular metabolism is usually altered, and end organ dysfunction is not only common, but also predictive of long-term morbidity and mortality. Clearly, interest is mitochondrial function both as a target for intracellular injury and response to extrinsic stress have been a major focus of basic science and clinical research into the pathophysiology of acute illness. However, mitochondria have multiple metabolic and signaling functions that may be central in both the expression of sepsis and its ultimate outcome. In this review, the authors address five primary questions centered on the role of mitochondria in sepsis. This review should be used both as a summary source in placing mitochondrial physiology within the context of acute illness and as a focal point for addressing new research into diagnostic and treatment opportunities these insights provide.

Cells of the innate and adaptive immune systems play a critical role in the host response to sepsis. Moreover, their accessibility for sampling and their capacity to respond dynamically to an acute threat increases the possibility that leukocytes might serve as a measure of a systemic state of altered responsiveness in sepsis.The working group of the 14th Acute Dialysis Quality Initiative (ADQI) conference sought to obtain consensus on the characteristic functional and phenotypic changes in cells of the innate and adaptive immune system in the setting of sepsis. Techniques for the study of circulating leukocytes were also reviewed and the impact on cellular phenotypes and leukocyte function of nonextracorporeal treatments and extracorporeal blood purification therapies proposed for sepsis was analyzed.A large number of alterations in the expression of distinct neutrophil and monocyte surface markers have been reported in septic patients. The most consistent alteration seen in septic neutrophils is their activation of a survival program that resists apoptotic death. Reduced expression of HLA-DR is a characteristic finding on septic monocytes, but monocyte antimicrobial function does not appear to be significantly altered in sepsis. Regarding adaptive immunity, sepsis-induced apoptosis leads to lymphopenia in patients with septic shock and it involves all types of T cells (CD4, CD8, and Natural Killer) except T regulatory cells, thus favoring immunosuppression. Finally, numerous promising therapies targeting the host immune response to sepsis are under investigation. These potential treatments can have an effect on the number of immune cells, the proportion of cell subtypes, and the cell function.

Contains fulltext : 172809.pdf (Publisher’s version ) (Closed access) Inflammation is a complex biologic response that is essential for eliminating microbial pathogens and repairing tissue after injury. AKI associates with intrarenal and systemic inflammation; thus, improved understanding of the cellular and molecular mechanisms underlying the inflammatory response has high potential for identifying effective therapies to prevent or ameliorate AKI. In the past decade, much knowledge has been generated about the fundamental mechanisms of inflammation. Experimental work in small animal models has revealed many details of the inflammatory response that occurs within the kidney after typical causes of AKI, including insights into the molecular signals released by dying cells, the role of pattern recognition receptors, the diverse subtypes of resident and recruited immune cells, and the phased transition from destructive to reparative inflammation. Although this expansion of the basic knowledge base has increased the number of mechanistically relevant targets of intervention, progress in developing therapies that improve AKI outcomes by modulation of inflammation remains slow. In this article, we summarize the most important recent developments in understanding the inflammatory mechanisms of AKI, highlight key limitations of the commonly used animal models and clinical trial designs that may prevent successful clinical application, and suggest priority approaches for research toward clinical translation in this area.

Supplemental digital content is available in the text., BACKGROUND Acute kidney injury (AKI) is an important complication in surgical patients. Existing biomarkers and clinical prediction models underestimate the risk for developing AKI. We recently reported data from two trials of 728 and 408 critically ill adult patients in whom urinary TIMP2•IGFBP7 (NephroCheck, Astute Medical) was used to identify patients at risk of developing AKI. Here we report a preplanned analysis of surgical patients from both trials to assess whether urinary tissue inhibitor of metalloproteinase 2 (TIMP-2) and insulin-like growth factor–binding protein 7 (IGFBP7) accurately identify surgical patients at risk of developing AKI. STUDY DESIGN We enrolled adult surgical patients at risk for AKI who were admitted to one of 39 intensive care units across Europe and North America. The primary end point was moderate-severe AKI (equivalent to KDIGO [Kidney Disease Improving Global Outcomes] stages 2–3) within 12 hours of enrollment. Biomarker performance was assessed using the area under the receiver operating characteristic curve, integrated discrimination improvement, and category-free net reclassification improvement. RESULTS A total of 375 patients were included in the final analysis of whom 35 (9%) developed moderate-severe AKI within 12 hours. The area under the receiver operating characteristic curve for [TIMP-2]•[IGFBP7] alone was 0.84 (95% confidence interval, 0.76–0.90; p < 0.0001). Biomarker performance was robust in sensitivity analysis across predefined subgroups (urgency and type of surgery). CONCLUSION For postoperative surgical intensive care unit patients, a single urinary TIMP2•IGFBP7 test accurately identified patients at risk for developing AKI within the ensuing 12 hours and its inclusion in clinical risk prediction models significantly enhances their performance. LEVEL OF EVIDENCE Prognostic study, level I.

Background and objectives Observational evidence has suggested that RRT modality may affect recovery after AKI. It is unclear whether initial choice of intermittent hemodialysis or continuous RRT affects renal recovery, survival, or development of ESRD in critically ill patients when modality choice is made primarily on hemodynamics. Design, setting, participants, & measurements We performed a retrospective cohort study examining adults (≥18 years old) admitted to intensive care units from 2000 to 2008 who received RRT for AKI and survived to hospital discharge or 90 days. We analyzed renal recovery (alive and not requiring RRT) and reasons for nonrecovery (death or ESRD) at 90 and 365 days. Conditional multivariable logistic regression was used to assess differences in renal recovery at 90 and 365 days between continuous RRT and intermittent hemodialysis. Models were stratified by propensity for continuous RRT and adjusted for age and reference creatinine. Results Of 4738 patients with Kidney Disease Improving Global Outcomes stage 3 AKI, 1338 (28.2%) received RRT, and 638 (47.7%) survived to hospital discharge (353 intermittent hemodialysis and 285 continuous RRT). Recovery from AKI was lower for intermittent hemodialysis versus continuous RRT at 90 days (66.6% intermittent hemodialysis versus 75.4% continuous RRT; P =0.02) but similar at 365 days (54.1% intermittent hemodialysis versus 59.6% continuous RRT; P =0.17). In multivariable analysis, there was no difference in odds of recovery at 90 or 365 days for patients initially treated with continuous RRT versus intermittent hemodialysis (90 days: odds ratio, 1.19; 95% confidence interval, 0.91 to 1.55; P =0.20; 365 days: odds ratio, 0.93; 95% confidence interval, 0.72 to 1.2; P =0.55). Conclusions We found no significant difference in hazards for nonrecovery or reasons for nonrecovery (mortality or ESRD) with intermittent hemodialysis versus continuous RRT. These results suggest that, when initial RRT modality is chosen primarily on hemodynamics, renal recovery and clinical outcomes in survivors are similar between intermittent hemodialysis and continuous RRT.

Continuous renal replacement therapy (CRRT) remains the dominant form of renal support among critically ill patients worldwide. Current clinical practice on CRRT prescription mostly relies on high quality studies suggesting no impact of CRRT dose on critically ill patients' outcomes. Recent clinical practice guidelines have been developed based on these studies recommending a static prescribed CRRT dose of 20-25 ml/kg/h. There is a rationale for renewed attention to CRRT prescription/practice based on the concept of dynamic solute control adapted to the changing clinical needs of critically ill patients. In response, Acute Disease Quality Initiative convened a 17th consensus meeting centered on re-evaluation of CRRT. This work group developed 4 themes focused specifically on CRRT dose prescription, delivery and solute control that were summarized in a series of consensus statements, along with the identification of critical knowledge gaps. CRRT dose prescription and delivery can be based on effluent flow rate. Delivered dose should be routinely monitored to ensure coherence with prescribed dose. CRRT dose should be dynamic, in recognition of between- and within-patient variation in targeted solute control or unintended solute clearance. Quality measures specific for monitoring delivered CRRT dose have been proposed that require further validation, prior to implementation, into the practice of guiding optimal CRRT dosage.

Fluid management during continuous renal replacement therapy (CRRT) in critically ill patients is a dynamic process that encompasses 3 inter-related goals: maintenance of the patency of the CRRT circuit, maintenance of plasma electrolyte and acid-base homeostasis and regulation of patient fluid balance. In this article, we report the consensus recommendations of the 2016 Acute Disease Quality Initiative XVII conference on ‘Precision Fluid Management in CRRT'. We discuss the principles of fluid management, describe various prescription methods to achieve circuit integrity and introduce the concept of integrated fluid balance for tailoring fluid balance to the needs of the individual patient. We suggest that these recommendations could serve to develop the best clinical practice and standards of care for fluid management in patients undergoing CRRT. Finally, we identify and highlight areas of uncertainty in fluid management and set an agenda for future research.

Acute Kidney Injury (AKI) is a common complication encountered among hospitalized patients, imposing significantly increased cost, morbidity, and mortality. Early prediction of AKI has profound clinical implications because currently no treatment exists for AKI once it develops. Feature selection (FS) is an essential process for building accurate and interpretable prediction models, but to our best knowledge no study has investigated the robustness and applicability of such selection process for AKI. In this study, we compared eight widely-applied FS methods for AKI prediction using nine-years of electronic medical records (EMR) and examined heterogeneity in feature rankings produced by the methods. FS methods were compared in terms of stability with respect to data sampling variation, similarity between selection results, and AKI prediction performance. Prediction accuracy did not intrinsically guarantee the feature ranking stability. Across different FS methods, the prediction performance did not change significantly, while the importance rankings of features were quite different. A positive correlation was observed between the complexity of suitable FS method and sample size. This study provides several practical implications, including recognizing the importance of feature stability as it is desirable for model reproducibility, identifying important AKI risk factors for further investigation, and facilitating early prediction of AKI.

Renal complications are common following heart and/or lung transplantation and lead to increased morbidity and mortality. Renal dysfunction is also associated with increased mortality for patients on the transplant wait list. Dialysis dependence is a relative contraindication for heart or lung transplantation at most centers, and such patients are often listed for a simultaneous kidney transplant. Several factors contribute to the impaired renal function in patients undergoing heart and/or lung transplantation, including the interplay between cardiopulmonary and renal hemodynamics, complex perioperative issues, and exposure to nephrotoxic medications, mainly calcineurin inhibitors.

Background We sought to determine the effects of alternative resuscitation strategies on microcirculatory perfusion and examine any association between microcirculatory perfusion and mortality in sepsis. Methods This was a prospective, formally designed substudy of participants in the Protocolized Care in Early Septic Shock (ProCESS) trial. We recruited from six sites with the equipment and training to perform these study procedures. All subjects were adults with septic shock, and each was assigned to alternative resuscitation strategies. The two main analyses assessed (1) the impact of resuscitation strategies on microcirculatory perfusion parameters and (2) the association of microcirculatory perfusion with 60-day in-hospital mortality. We measured sublingual microcirculatory perfusion using sidestream dark field in vivo video microscopy at the completion of the 6-h ProCESS resuscitation protocol and then again at 24 and 72 h. Results We enrolled 207 subjects (demographics were similar to the overall ProCESS cohort) and observed 40 (19.3%) deaths. There were no differences in average perfusion characteristics between treatment arms. Analyzing the relationship between microcirculatory perfusion and mortality, we found an association between vascular density parameters and mortality. Total vascular density (beta = 0.006, p

Background: Numerous studies have suggested a possible role for acute kidney injury (AKI) biomarkers in predicting renal recovery both before and after renal replacement therapy (RRT). However, definitions for recovery and whether to include patients dying but free of RRT may influence results. Objectives: To validate plasma neutrophil gelatinase-associated lipocalin (pNGAL) as a useful biomarker for predicting or improving the ability of clinical predictors alone to predict recovery following AKI, including in our model plasma B-type natriuretic peptide (pBNP) to account for cardiovascular events. Methods: We analyzed 69 patients enrolled in the Acute Renal Failure Trial Network study. pNGAL and pBNP were measured on days 2, 7, and 14. We analyzed their predictive ability for subsequent recovery, defined as alive and independent from dialysis in 60 days. In sensitivity analyses, we explored changes in results with alternative definitions of recovery. Results: Twenty-nine patients (42%) recovered from AKI. Neither pNGAL nor pBNP, alone or in combination, was accurate predictors of renal recovery-the best area under the receiver-operating characteristics curve (AUC) was for pNGAL using the largest relative change (AUC 0.59, 95% CI 0.45–0.74). The best clinical model achieved superior performance to biomarkers (AUC 0.69, 95% CI 0.56–0.81). The AUC was greatest (0.75, 95% CI 0.60–0.91) when pNGAL + pBNP on day 14 were added to the clinical model but this increase did not achieve statistical significance. However, integrated discrimination improvement analysis showed that the addition of pNGAL and pBNP on day 14 to the clinical model significantly improved the prediction of renal recovery (p = 0.008). Conclusions: pNGAL and pBNP can improve the accuracy of clinical parameters in predicting AKI recovery and a full model using biomarkers together with age achieved adequate discrimination.

Background Recent randomized trials have not found that polymyxin B hemoperfusion (PMX-HP) improves outcomes for patients with sepsis. However, it remains unclear whether the therapy could provide benefit for highly selected patients. Monocyte human leukocyte antigen (mHLA-DR) expression, a critical step in the immune response, is decreased during sepsis and leads to worsening sepsis outcomes. One recent study found that PMX-HP increased mHLA-DR expression while another found that the treatment removed HLA-DR-positive cells. Methods We conducted a randomized controlled trial in patients with blood endotoxin activity assay (EAA) level ≥ 0.6. Patients in the PMX-HP group received a 2-h PMX-HP treatment plus standard treatment for 2 consecutive days. Patients in the non-PMX-HP group received only standard treatment. The primary outcome compared the groups on median change in mHLA-DR expression between day 3 and baseline. Secondary outcomes compared the groups on the mean or median change in CD11b expression, neutrophil chemotaxis, presepsin, cardiovascular Sequential Organ Failure Assessment (CVS SOFA) score, vasopressor dose, and EAA level between day 3 and baseline. We further compared the groups on mortality, ICU-free days, ventilator-free days, dialysis dependence status, renal recovery, serum creatinine, vasopressor-free days, and major adverse kidney events (MAKE 28), measured on day 28. Results Fifty-nine patients were randomized to PMX-HP (n = 29) and non-PMX-HP (n = 30) groups. At baseline, mHLA-DR expression, CD11b, neutrophil chemotaxis, and clinical parameters were comparable between groups. The median change in mHLA-DR expression between day 3 and baseline was higher in PMX-HP patients than in patients receiving standard therapy alone (P = 0.027). The mean change in CD11b between day 3 and baseline was significantly lower in the PMX-HP group than in the non-PMX-HP group (P = 0.002). There were no significant changes from baseline in neutrophil chemotaxis, presepsin, CVS SOFA scores, vasopressor doses, or EAA level between groups. On day 28 after enrollment, mortality, ICU-free days, ventilator-free days, dialysis dependence status, renal recovery, serum creatinine, vasopressor-free days, and MAKE 28 were comparable between groups. Conclusion PMX-HP improved mHLA-DR expression in severe sepsis patients. Future studies should examine the potential benefit of PMX-HP in patients with low mHLA-DR expression. Trial registration ClinicalTrials.gov, NCT02413541. Registered on 3 March 2015. Electronic supplementary material The online version of this article (10.1186/s13054-018-2077-y) contains supplementary material, which is available to authorized users.

Neurocritical Care provides “at the bedside” guidance on the medical knowledge and technical skills required to care for critically ill patients with neurologic conditions such as cerebrovascular disorders, neurotrauma, neuro-oncology, refractory seizures, neuromuscular diseases, infections, alterations in consciousness, and perioperative neurosurgical care. It provides information on the clinical conditions, basic and advanced neuro-monitoring, and addresses some unique special populations. Part of the Pittsburgh Critical Care Medicine series, this compact volume is an ideal reference for physicians and trainees working in either a general intensive care unit or specialty neurointensive care unit. Readers will gain an understanding of background knowledge and concrete solutions to questions and situations encountered in daily practice.

Acute kidney injury (AKI) is a commonly encountered syndrome associated with various aetiologies and pathophysiological processes leading to decreased kidney function. In addition to retention of waste products, impaired electrolyte homeostasis and altered drug concentrations, AKI induces a generalized inflammatory response that affects distant organs. Full recovery of kidney function is uncommon, which leaves these patients at risk of long-term morbidity and death. Estimates of AKI prevalence range from

Acute kidney injury (AKI) is a frequent complication of sepsis and contributes to increased morbidity and mortality. Urinary tissue inhibitor of metalloproteinases-2 (TIMP2) has been recently recognized as an early biomarker to predict AKI in critically ill patients. However, the biological functions of TIMP2 remain largely unknown. In this study, we investigated the role of TIMP2 in mediating inflammation and tubular cell apoptosis in AKI. In kidney tissue taken from mice exposed to cecal ligation and puncture (CLP) and in human kidney 2 (HK-2) cells exposed to lipopolysaccharide (LPS) in culture, TIMP2 expression was significantly upregulated. The expression of TIMP2 in the kidney tissue correlated with the severity of AKI in vivo. In cultured HK-2 cells, LPS challenge markedly induced cytokine release, and recombinant cytokines promoted TIMP2 expression and apoptosis. However, TIMP2 silencing ameliorated LPS-induced cytokine release, apoptosis, and cell injury. We further found that the effects of downregulation of TIMP2 on a suppression of release of inflammatory cytokines were mediated by p-P65. Stable, kidney-specific TIMP2 knockdown mice were transduced by injecting the TIMP2 knockdown lentiviral vector into kidney parenchyma. TIMP2 silencing ameliorated CLP-induced proinflammatory cytokines, kidney dysfunction as measured by serum creatinine level, and histopathological changes. Downregulation of TIMP2 showed renoprotective effects on endotoxin-induced AKI, which was associated with the anti-inflammatory activity through inhibition of the nuclear factor (NF)-κB pathway. Collectively, our results indicate that TIMP2 plays an important role in mediating sepsis-induced AKI through regulation of NF-κB. These findings reveal the pathogenic role of TIMP2 in AKI and suggest a novel target for the treatment of AKI.

Study objective Acute kidney injury (AKI) is a common condition associated with both short-term and long-term consequences including dialysis, chronic kidney disease, and mortality. Although the United States Food and Drug Administration Adverse Event Reporting System (FAERS) database is a powerful tool to examine drug-associated events, to our knowledge, no study has analyzed this database to identify the most common drugs reported with AKI. The objective of this study was to analyze AKI reports and associated medications in the FAERS database. Design Retrospective pharmacovigilance disproportionality analysis. Data source Food and Drug Administration Adverse Event Reporting System database. Measurements and main results We queried the FAERS database for reports of AKI from 2004 quarter 1 through 2015 quarter 3. Extracted drugs were assessed using published references and categorized as known, possible, or new potential nephrotoxins. The reporting odds ratio (ROR), a measure of reporting disproportionality, was calculated for the 20 most frequently reported drugs in each category. We retrieved 7,241,385 adverse event reports, of which 193,996 (2.7%) included a report of AKI. Of the AKI reports, 16.5% were known nephrotoxins, 18.6% were possible nephrotoxins, and 64.8% were new potential nephrotoxins. Among the most commonly reported drugs, those with the highest AKI ROR were aprotinin (7614 reports; ROR 115.70, 95% confidence interval [CI] 110.63-121.01), sodium phosphate (1687 reports; ROR 55.81, 95% CI 51.78-60.17), furosemide (1743 reports; ROR 12.61, 95% CI 11.94-13.32), vancomycin (1270 reports, ROR 12.19, 95% CI 11.45-12.99), and metformin (4701 reports; ROR 10.65, 95% CI 10.31-11.00). The combined RORs for the 20 most frequently reported drugs with each nephrotoxin classification were 3.71 (95% CI 3.66-3.76) for known nephrotoxins, 2.09 (95% CI 2.06-2.12) for possible nephrotoxins, and 1.55 (95% CI 1.53-1.57) for new potential nephrotoxins. Conclusion Acute kidney injury was a common reason for adverse event reporting in the FAERS. Most AKI reports were generated for medications not recognized as nephrotoxic according to our classification system. This report provides data on medications needing further research to determine the risk of AKI with these new potential nephrotoxins.

Acute kidney injury (AKI) occurs in 7% to 18% of hospitalized patients and complicates the course of 50% to 60% of those admitted to the intensive care unit, carrying both significant mortality and morbidity.[1][1] Even though many cases of AKI are reversible within days to weeks of occurrence, data

Two new clinical trials together involving nearly 30,000 patients support previous observational evidence that the most common solution used for intravenous fluid therapy in the world is associated with kidney damage. Both trials found that 0.9% saline was inferior to solutions with more physiological chloride concentrations and resulted in greater rates of major adverse kidney events.