Contributions to nephrology
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Extracorporeal therapies are able to sustain life through different mechanisms. This approach, called multiple organ support therapy, can in fact obtain blood purification by hemodialysis/hemofiltration to replace kidney function, temperature control, electrolyte and acid-base control to mimic homeostatic regulation of the kidney and circulation, fluid balance control to support the right hydration and cardiac performance, cardiac support removing cardiodepressant substances and equilibrating potassium levels, blood detoxification and liver support by coupled plasma filtration and adsorption or direct adsorption on blood (hemoperfusion), immunomodulation and endothelial support in the presence of sepsis by cutting the peaks of pro- and anti-inflammatory mediators, and immunoadsorption or adsorption of specific substances such as endotoxin. ⋯ Today this is made possible by removal of CO(2) either by complete extracorporeal membrane oxygenation or by using decapneization in conjunction with hemofiltration in a system called DECAP/DECAPSMART. In conclusion, circulating blood outside the body and treating it with different filters or cartridges in a multiple organ support therapy may represent an important support for multiple organ dysfunction conditions induced by sepsis, acute respiratory distress syndrome and in recent times by complicated H1N1-related infections.
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Renal replacement therapy (RRT) is an important therapeutic and supportive measure for acute kidney injury (AKI) in the critical care setting. While RRT is extensively used in clinical practice, there remains uncertainty about the ideal circumstances of when to initiate RRT and for what indications. Many factors, including logistics, resource availability, physician experience and patient-related factors are involved in the decision of when to start and stop RRT for those with AKI. ⋯ This algorithm was developed using available clinical evidence, recognizing the inherent limitations of observational studies. It aims to provide a starting point for clinicians and future prospective studies. We also review the available literature on discontinuation of RRT and propose a few simple recommendations on how to 'wean' patients from RRT.
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There is a large amount of support for the safety of polymyxin-B (PMX-B) hemoperfusion in the treatment of septic shock from Japan and Europe. There is also support for potential efficacy, although randomized controlled trials are few and conflicting. ⋯ The variability in the number of treatment cartridges used, the selection of subjects based on likelihood of endotoxin presence without endotoxin measurement, and small sample sizes in mainly single-center trials have also been cited. The newly designed EUPHRATES trial (Evaluating Use of Polymyxin Hemoperfusion in a Randomized Controlled Trial of Adults treated for Endotoxemia and Septic Shock) addresses many of the methodological issues and represents a significant opportunity to test for clinical efficacy of endotoxin removal in the critically ill septic patient.
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Intravenous fluids are commonly administered to patients with developing septic acute kidney injury (AKI). Conversely, fluids are just as commonly removed with diuretics or renal replacement therapy (RRT) techniques or ultrafiltration in patients with cardiorenal syndromes (CRS). In both groups, there is controversy regarding fluid management. ⋯ However, in patients with either septic AKI or CRS, hypovolemia and renal hypoperfusion can occur if excessive fluid removal is pursued with diuretics or extracorporeal therapy. Thus, accurate assessment of fluid status and careful definition of targets are needed to improve clinical outcomes. Controlled studies of conservative versus liberal fluid management in patients with AKI or CRS seem justified.
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The care of acute kidney injury (AKI) in critically ill children shares several features with adult AKI with some critical distinctions: in both settings, however, the exact identification of renal dysfunction, in-depth knowledge of disparate risk factors and patient-specific management are the primary targets in order to provide optimal care. This article will specifically review recent work published on pediatric AKI about definition and epidemiology, the possible etiologies in specific conditions, and the newest laboratory investigations necessary to diagnose AKI severity. A short description of pediatric renal replacement therapies and their potential application to extracorporeal membrane oxygenation will also be described.