Better removal of small solutes by more frequent hemodialysis sessions than by conventional, thrice weekly hemodialysis sessions of similar weekly duration.

摘要

It has been suggested that conventional, thrice weekly (4 or less hours per session) hemodialysis regimen is an "unphysiological" modality of treatment (1). However, many investigators are of the opinion that proper scientific studies are necessary before more intensive dialytic therapies can be accepted as a mainstream medical practice (2-5). While the possible superiority of shorter but more frequent hemodialysis is being investigated (2-6), many authors have noted that there is a greater removal of small solutes per unit time during shorter but more frequent dialysis runs when compared to the conventional approach (7-13). This phenomenon occurs because the concentration gradient between plasma and dialysate of a small solute such as urea is higher during the first 2 hours than during the last 2 hours of a 4-hour dialysis treatment, thus fostering better diffusion of the small solute during the former period. The above phenomenon is illustrated in the following figure in which the curvilinear declinein blood urea concentration with time on hemodialysis (14) is shown.