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Luciano A Pedrini

Publications and source records attributed to Luciano A Pedrini.

6 recordsLinked to original sources
PubMed2003

On-line mixed hemodiafiltration with a feedback for ultrafiltration control: effect on middle-molecule removal.

BACKGROUND: Increased middle-molecular uremic toxin removal seems to favorably influence survival in dialysis patients. The aim of this study was to verify if, in on-line mixed hemodiafiltration, solute removal by convection may be enhanced by forcing the ultrafiltration rate (QUF) and optimizing the infusion technique in order to achieve the highest possible filtration fraction (FF). METHODS: Removal of beta2-microglobulin (beta2-m), urea, creatinine, and phosphate were compared in 20 patients randomly submitted to one dialysis session (A), one postdilution hemodiafiltration session (B), and three sessions of mixed hemodiafiltration (C, D, and E) at different infusion rates (QS). In mixed hemodiafiltration, a newly developed feedback system automatically maintained the transmembrane pressure (TMP) within its highest range of safety (250 to 300 mm Hg) at constant QUF, while ensuring the maximum FF by splitting infusion between pre- and postdilution. RESULTS: A mean QS of 134 +/- 20 mL/min (mean FF = 0.65) was attained in post-HDF, and up to 307 +/- 41 mL/min (mean FF = 0.69) in mixed hemodiafiltration. The mean dialysate clearances (KDQ) for all tested solutes and urea eKt/V were significantly higher in all hemodiafiltration sessions than in dialysis. Only in the case of urea did the infusion mode have no significant effect. KDQ for beta2-m was maximal in session D and significantly higher than in session B (90.2 +/- 11 mL/min vs. 77.5 +/- 11 mL/min; P = 0.02). KDQ for beta2-m significantly correlated with QS and the plasma water flow rate (QPW). The highest KDQ for beta2-m was found at values of QS approximately QPW. Beyond this value KDQ decreased. CONCLUSION: The mixed infusion mode in hemodiafiltration, controlled by the TMP-ultrafiltration feedback, seems to improve the efficiency of hemodiafiltration by fully exploiting the convective mechanism of solute removal. The feedback automatically adjusted the infusion rate and site to the maximum FF taking into account flow conditions, internal pressures, and hydraulic permeability of the dialyzer and their complex interactions.

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On-line hemodiafiltration: technique and efficiency.

Hemodiafiltration (HDF) is the strategy enabling the high potential of hydraulic and solute permeability of synthetic membranes to be most properly exploited. On-line production of unlimited amount of sterile dialysate at low cost has favored its extensive diffusion in the recent years. However, to achieve the most efficient convective transport, ultrafiltration rate must be forced towards its physical limits, paying attention to the safety of the patient and to the integrity of the system. The infusion mode variably influences the dialyzer performance and the efficiency of the technique. With respect to standard and high-flux hemodialysis (HD), increased removal of solutes in the small and middle molecular weight range was reported with on-line HDF in several recent studies. Some of these compounds have a pathogenic role or are markers of the most frequent long-term complications and causes of death in HD patients, such as dialysis related amyloidosis, cardiovascular disease, inflammation and malnutrition. Even in the absence of definite evidence, coming from large data base studies, there are strong indications to advise the use of this dialytic strategy, which combines the benefits of the high biocompatibility of the membrane and the sterile dialysis fluid with increased removal by convection of middle-molecular uremic toxins. A new mode of infusion in on-line HDF--the mixed infusion mode--is here described, which is able to achieve and maintain the maximum possible water and solute removal during the sessions through a feedback control of the transmembrane pressure.

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