Who is the winner, pre-, post-, or mixed-dilution hemodiafiltration?

Abstract

Online hemodiafiltration (HDF) is the most technologically advanced renal replacement therapy, combining convective and diffusive solute removal. Online HDF removes a larger volume of small and middle molecule uremic toxins compared to conventional hemodialysis (HD). Recent clinical trials demonstrated that HDF improves patient survival when adequate convection volumes are achieved [1,2]. Online HDF is more complex than conventional HD. Various modes of online HDF, differing by the site of replacement fluid infusion, are in use. The replacement fluid can be infused into the tubing downstream of the dialyzer (postdilution), upstream of the dialyzer (predilution), both upstream and downstream (mixed dilution), or into the middle of the dialyzer blood pathway (mid-dilution). Each has its strengths and limitations (Table 1).Postdilution mode is the most common method of fluid substitution in online HDF. Postdilution HDF is the most effective method in terms of solute removal. However, it can increase the viscosity of the blood before fluid substitution, which results in deposition of plasma proteins on the membrane surface, clogging of membrane pores, increased transmembrane pressure (TMP), and occlusion of dialyzer blood channels [1]. Hemoconcentration generally limits

Intradialytic Tolerance and Recovery Time in Different High-Efficiency Hemodialysis Modalities

“…PRE-HDF resolves this problem but requires about three times more replacement fluid than POST-HDF. This reduces the risks of clotting and protein deposition and allows much higher ultrafiltration rates up to 100% of the blood flow rate which can be far lower than in POST-HDF [31]. The cooling effect of replacement solution in large volumes may help maintain hemodynamic stability as well [32].…”

“…At the opposite extreme are POST-HDF sessions, during which at least one side effect was observed in almost 42% of patients. The largest number of clotting events is noteworthy, which is fully understandable considering the highest degree of hemoconcentration in the dialyzer, increase the viscosity of the blood before fluid substitution, which results in deposition of plasma proteins on the membrane surface, clogging of membrane pores, increased transmembrane pressure, and occlusion of dialyzer blood channels [31]. There are no similar studies comparing all high-efficiency dialysis modalities in this regard.…”

Intradialytic Tolerance and Recovery Time in Different High-Efficiency Hemodialysis Modalities

“…At least one AE was observed in almost 42% of POST-HDF sessions. The largest number of clotting events is noteworthy, which is fully understandable considering the highest degree of hemoconcentration during POST-HDF in the dialyzer, increasing the viscosity of the blood before fluid substitution, which results in the deposition of plasma proteins on the membrane surface, the clogging of membrane pores, an increased transmembrane pressure and an occlusion of dialyzer blood channels [30]. PRE-HDF resolves this problem but requires about three times more replacement fluid than POST-HDF.…”

Intradialytic Tolerance and Recovery Time in Different High-Efficiency Hemodialysis Modalities

“…At least one AE was observed in almost 42% of POST-HDF sessions. The largest number of clotting events is noteworthy, which is fully understandable considering the highest degree of hemoconcentration during POST-HDF in the dialyzer, increase the viscosity of the blood before fluid substitution, which results in deposition of plasma proteins on the membrane surface, clogging of membrane pores, increased transmembrane pressure, and occlusion of dialyzer blood channels [30]. PRE-HDF resolves this problem but requires about three times more replacement fluid than POST-HDF.…”