3 High-Efficiency and High-Flux Hemodialysis

Hemodialysis remains the major modality of renal replacement therapy in the United States. Since the 1970s the drive for shorter dialysis time with high urea clearance rates has led to the development of high-efficiency hemodialysis. In the 1990s, certain biocompatible features and the desire to remove amyloidogenic 2microglobulin has led to the popularity of high-flux dialysis. During the 1990s, the use of high-efficiency and high-flux membranes has steadily increased and use of conventional membrane has declined [1]. In 1994, a survey by the Centers for Disease Control showed that high-flux dialysis was used in 45% and high-efficiency dialysis in 51% of dialysis centers (Fig. 3-1) [1]. Despite the increasing use of these new hemodialysis modalities the clinical risks and benefits of high-performance therapies are not welldefined. In the literature published over the past 10 years the definitions of high-efficiency and high-flux dialysis have been confusing. Currently, treatment quantity is not only defined by time but also by dialyzer characteristics, ie, blood and dialysate flow rates. In the past, when the efficiency of dialysis and blood flow rates tended to be low, treatment quantity was satisfactorily defined by time. Today, however, treatment time is not a useful expression of treatment quantity because efficiency per unit time is highly variable. Sivasankaran Ambalavanan Gary Rabetoy Alfred K. Cheung