The optimal timing of hemoperfusion component in combined hemodialysis-hemoperfusion treatment for uremic toxins removal.

The combination of hemodialysis-hemoperfusion (HDHP) has been proved to be superior to hemodialysis (HD) in eliminating uremic toxins. There are two methods of combination of HD and HP: the HP regime is utilized during the first two-hour an early HP conducted HDHP (EHDHP) or the last two-hour late HP conducted HDHP (LHDHP) of 4 h regular HD session. The present study was to compare these two methods in uremic toxins removal. Twenty adult chronic HD patients were enrolled in this self-control method study. The patients were randomized to receive one session of EHDHP or LHDHP. Two weeks later, the dialysis modalities were switched. The reduction ratio (RR) of targeted uremic toxins for each session was assessed. Both EHDHP and LHDHP showed a significant removal of small water-soluble solutes, middle-sized toxins and cytokines as well (p < 0.05). There were no significant differences between two methods in RR of small water-soluble solutes, like urea and creatinine. For middle-sized molecules and cytokines, such as PTH, β(2)-M, IL-1, IL-6, and TNF-α, the RR was markedly increased in LHDHP than that in EHDHP (p < 0.05). LHDHP showed no more intradialytic events than EHDHP. The combination of HD and HP in the last two hours in one hemodialysis session had more effect on eliminating middle-sized toxins and cytokines.