Fluid management in continuous renal replacement therapy

The purpose of intravenous fluid administration is to increase cardiac output. Excessive fluid administration can lead to accumulation of interstitial fluid, worsening hypoperfusion and hence develop organic dysfunction. Therefore, fluid overload is a poor prognostic factor for hospitalized patients and those admitted to the Intensive Care Unit (ICU). A resuscitation strategy divided in four phases has been described; the last phase consists in the elimination of those fluids that have been administrated in the previous phases. When fluid overload is complicated by acute kidney injury renal replacement therapy may be used for this purpose. A successful fluid treatment of a patient depends on a proper, accurate and frequent evaluation, and in the correct understanding of the basic principles and clear objectives of the treatment. In the continuous renal replacement therapy, the rate of the fluid eliminated can be adjusted safely according to each patient needs and it allows additional support of other complications. The ideal strategy to guide the elimination rate is unknown. This review presents the basic principles for an optimum fluid management in the continuous renal replacement therapy.