Abstract
The prognosis of patients with an acute accumulation of pathogenic or toxic substances in their body fluids--a condition that severely affects survival--can be significantly improved by blood purification. The most appropriate blood purification method and the duration for which it should be used must be selected on the basis of efficacy and cost. Several blood purification techniques--such as hemodialysis (HD), hemofiltration (HF), hemodiafiltration, continuous hemofiltration (CHF), hemadsorption and plasma exchange--have been developed. Each modality has different removal capacities and limitations; therefore, it is necessary to thoroughly evaluate the time and the duration of use in the case of different disease conditions. The survival rate of patients treated with HF with 35 ml/min of average filtrate is higher than that observed after conventional HD. In patients with systemic inflammatory response syndrome and multiple organ dysfunction syndrome, proinflammatory cytokines should be removed by HF or CHF, as should the toxins accumulated in the original disease. Thus far, no ideal filter has been developed for the removal of a considerable amount of proinflammatory cytokines with minimal albumin loss. In the case of acute liver failure, ammonia, amino acid metabolites and albumin-binding bilirubin should be removed by a combination of HF and plasma exchange. The use of fresh frozen plasma as a replacement fluid in plasma exchange is also important in order to replenish the deficient coagulation factors and essential metabolic factors. Activation of tissue/organ regeneration by the removal of pathogenic factors or by the substitution of factors essential for regeneration might be important in the case of multiple organ dysfunction syndrome. In critically ill patients with composite conditions, the use of more than two blood purification techniques at the same time or at different times during the course of the diseases can improve patient prognosis more than the use of single methods.
