**4.1 Hemofiltration and hemodiafiltration**

Hemodiafiltration is a form of chronic renal replacement therapy used most in Europe, particularly Germany and Belgium, and very rarely used currently in the United States (46). Based upon relatively better clearance of larger "middle" molecules through solvent drag, some claim that replacement therapy with hemodiafiltration may be superior to that with hemodialysis, including improved hemodynamics.

For chronic renal replacement therapy, the two principal regimens used to provide substantial removal of larger MW uremic toxins via convection are intermittent hemofiltration (HF) and intermittent hemodiafiltration (HDF). Daily convective therapy has also been used.


For chronic renal replacement therapy, the standard regimen for both HF and HDF includes three sessions per week for three to five hours, as with conventional intermittent hemodialysis. A typical conservative (or high dose) regimen for HDF includes a post dilution configuration with a blood flow of 300 mL/min (500 mL/min for high dose), a dialysate flow of 500 mL/min, a flow of a substitution volume of 60 mL/min (120 mL/min for high dose) and a high flux dialyzer of 1.4 m2 (2.2 m2 for high dose) (47).

Several small studies using daily HF/HDF have been published.


Uldall started the first quotidian (daily) nocturnal hemodialysis program in 1994 at the Wellesley Hospital in Toronto (40). Since then, its use has been extended to more centers in Canada, the United States, Australia, and several European countries (41-44). This hemodialysis modality is performed five to seven times per week, with each treatment lasting 6 to 8 hours. Although the number of patients studied has been rather limited, but these evidence suggest signficant improvements in caloric intake and serum albumin

Long intermittent hemodialysis is given three times a week and a dialysis time of 6 to 8 hours. This procedure is practiced in Tassin, France, and has been associated with

Although, no data on randomized controlled trials are available on home hemodialysis, some recent well-conceived cohort studies have indicated that outcome of home (daily) HD is superior to conventional in-centre dialysis, and even equal to cadaveric transplantation,

Hemodiafiltration is a form of chronic renal replacement therapy used most in Europe, particularly Germany and Belgium, and very rarely used currently in the United States (46). Based upon relatively better clearance of larger "middle" molecules through solvent drag, some claim that replacement therapy with hemodiafiltration may be superior to that with

For chronic renal replacement therapy, the two principal regimens used to provide substantial removal of larger MW uremic toxins via convection are intermittent hemofiltration (HF) and intermittent hemodiafiltration (HDF). Daily convective therapy has

 Hemofiltration — With HF, fluid is removed by the dialysis machine through increased transmembrane pressure and the replacement solution is infused intravenously at equal volume minus the desired fluid volume removal. The clearance of the method for a particular solute is dictated by the ultrafiltration volume and the sieving coefficient. As the sieving coefficient for low MW unbound solutes equals 1, the clearance for small molecules equals the ultrafiltrate volume. Although hemofiltration is effective in the removal of the larger MW solutes, it is less effective in the removal of small molecules

 Hemodiafiltration — HDF is a combination of hemodialysis and hemofiltration devised to overcome the low clearance of small solutes by hemofiltration by adding a diffusive

For chronic renal replacement therapy, the standard regimen for both HF and HDF includes three sessions per week for three to five hours, as with conventional intermittent hemodialysis. A typical conservative (or high dose) regimen for HDF includes a post dilution configuration with a blood flow of 300 mL/min (500 mL/min for high dose), a dialysate flow of 500 mL/min, a flow of a substitution volume of 60 mL/min (120 mL/min

One study that addressed the short term effects of daily HF reported that predialysis

 In one study in which 12 patients switched from HD to HF at home on a daily basis for one month, HF was associated with a lower blood pressure, higher caloric intake, and

for high dose) and a high flux dialyzer of 1.4 m2 (2.2 m2 for high dose) (47).

Several small studies using daily HF/HDF have been published.

beta-2-microglobulin levels decreased by 40 percent (48).

improvements in blood pressure control and better overall nutritional status.

when differences in case mix are taken into account (45).

hemodialysis, including improved hemodynamics.

as it is restricted by the ultrafiltration volume.

**4.1 Hemofiltration and hemodiafiltration** 

results.

also been used.

component.

improved quality of life, findings consistent with previous reports on short daily HD (49-50). A trend toward a decrease in serum beta-2-microglobulin could be ascribed to the HF alone. The infusion volume used was 40 percent of total body water, which offered a standard Kt/V of approximately 2.0.

 In another study of eight patients undergoing in center daily hemodiafiltration for six months, there were lower serum levels of predialysis BUN and creatinine (which were expected by the change to a daily schedule), as well as lower levels of other solutes including beta-2-microglobulin and homocysteine (51). Additional benefits included improved phosphate control, discontinuation of all antihypertensive agents, and a 30 percent regression in left ventricular mass. Although some of these results can be attributed to the daily treatment schedule, the decrease in the pretreatment levels of beta-2-microglobulin and the improvement in phosphate control are clearly attributable to both convection and the increased treatment frequency.
