Contributions to nephrology
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Continuous hemoperfusion therapies are now widely used in critical care, and could prove to be life-saving for patients unable to receive regular hemoperfusion treatments. Unfortunately, due to the inherent difficulties in assessing the effects of treatment upon critically ill patients, the efficacy of this modality has yet to be proven. Instead of focusing exclusively on a particular form of continuous hemoperfusion or a direct comparison between the different types available, this report provides a general overview of the studies reporting on its efficacy across a wide range of conditions. The authors conclude that continuous hemoperfusion could be beneficial in some cases, but this is highly dependent upon the particular modality used.
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Continuous renal replacement therapy (CRRT) has been extensively used in Japan as renal support for critically ill patients managed in the ICU. In Japan, active research has also been conducted on non-renal indications for CRRT, i.e. the use of CRRT for purposes other than renal support. Various methods of blood purification have been attempted to remove inflammatory mediators, such as cytokines, in patients with severe sepsis or septic shock. ⋯ In evaluating the efficacy of CRRT for non-renal indications, it is essential to focus on patients subjected to be studied, such as severe sepsis or septic shock, and to evaluate its indication, commencement, termination of therapy and also its therapeutic effects based on analysis of blood levels of the target substances to be removed (e.g. cytokines). IL-6 blood level appears to be useful as a variable for this evaluation. It is expected that evidence endorsing the validity of these methods now being attempted in Japan will be reported near future.
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Fluid overload may occur in patients with heart failure. Further complications may arise when cardiorenal syndromes develop and the kidneys are unable to eliminate the accumulated fluid. Diuretics represent the fist line of treatment, although in some case they may be ineffective or even dangerous for the patient. ⋯ Then, an evaluation of biomarkers of heart failure and a careful analysis of body fluid composition by bioimpedance vector analysis should be carried out to establish the level of hydration and to guide fluid removal strategies. Last but not least, an adequate extracorporeal technique should be employed to remove excess fluid. Preference should be given to continuous forms of ultrafiltration (slow continuous ultrafiltration, continuous venovenous hemofiltration); these techniques guided by a continuous monitoring of circulating blood volume allow for an adequate restoration of body fluid composition minimizing hemodynamic complications and worsening of renal function especially during episodes of acute decompensated heart failure.
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Diuretics are commonly used in the intensive care unit, especially for patients with oliguric acute kidney injury. This practice is controversial since there is a lack of evidence regarding any beneficial effects of diuretics either on prevention or treatment of acute kidney injury. ⋯ However, diuretics can minimize fluid overload, making patient management easier and potentially avoiding many cardiopulmonary and non-cardiopulmonary complications. We will briefly review the available evidence for and against the use of diuretics in the critically ill, including cardiorenal syndromes.
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In critically ill patients, fluid balance management is an integral part of the process of care. In patients in shock or severe sepsis, aggressive initial fluid resuscitation has been shown to improve overall prognosis. ⋯ Randomized clinical trials are urgently required to assess the role of fluid overload in mortality and morbidity in this population. In the meantime, we should not only focus on acute fluid resuscitation but also on cumulative fluid balance as the amount and duration of fluid accumulation may influence outcomes.