1. FREQUENT HEMODIALYSIS
AND OUTCOME
Dr. Sandeep G Huilgol
MBBS., DNB (Internal Medicine)., MMedSci(Nephrology)

2. PURPOSE OF THE STUDY
• Despite the increasing efforts in adequate dialysis in the
mortality of patients still remains high according to US
and UK registries. (24-30 % mortality)
• The causes of high mortality of patients still remain
elusive.
• Adequacy of hemodialysis is being measured on the basis
of urea reduction ratio which has improved over the
years in various centers throughout the world.
• But as mortality has not improved much, various other
factors were thought of like beta-2 microglobulin, blood
pressure variability and Phosphorus etc.

3. • To concentrate the efforts on the adequacy of dialysis based
on these factors various observational studies as well some
RCTs were conducted by increasing the dialysis duration and
frequency, and to better understand the kinetics of their
removal.
• Any Indian study of frequent dialysis is not known.

4. GOALS OF HEMODIALYSIS AND ITS KINETICS
• The primary goal of hemodialysis is to restore the
intracellular and extracellular fluid environment that
is characteristic of normal kidney function.
• This is accomplished by the movement of solutes
such as urea from the blood into the dialysate.
• Solute concentration and molecular weight are
the primary determinants of diffusion rates.

5. • Small molecules such as urea diffuse quickly
• Larger molecules such as
– phosphate,
– β (Beta) 2 microglobulin, and
– albumin (because it is retained in the vascular
compartment as it is not permeable through the
endothelial surface)
are compartmentalized and thus diffuse much more
slowly.

6. Taken from : Hemodialysis, Jonathan Himmelfarb et al. N Engl J Med 2010;363:1833-45

7. Panel A
• Low-molecular-weight solutes such as urea are readily
dialyzed.
• The efficiency of total urea removal declines over the course
of treatment because of decreasing plasma urea
concentrations.
• After dialysis, there is a rebound in urea levels.

9. Panel B and C
• For compartmentalized solutes, such as phosphate, the
plasma space is rapidly cleared (Panel B)
• Whereas most phosphate in cells and bone remains there.
• After dialysis, there is much rapid rebound in the plasma
phosphate concentration because of equilibration of the
body compartments;
• Thus, overall removal is inefficient.
• Longer dialysis time provides more effective clearance or
the dialysis process should be more frequent.

10. • Dialysis of Beta-2 microglobulin is also limited
because of compartmentalization.
• Similar is the case with protein bound substances
because protein binding limits the free-solute
concentration, which is the driving force for
diffusion (Panel C).
• Similar to panel B frequent dialysis might help in
the complete removal.

11. EFFECTS OF INCREASING THE DOSE OF
HEMODIALYSIS
• Well powered trials done earlier NCDS and HEMO did
not show any improvement in the all cause mortality
or outcome with increased dose of hemodialysis.
• Hence novel approach was necessary.

12. FREQUENT HEMODIALYSIS
• Frequent Hemodialysis is based on the concept that
middle molecules which are compartmentalized can
be removed by increasing the frequency of dialysis.
• Various observational studies have been done and
recent Frequent Hemodialysis Network trial (RCT)
published recently.
• Most have shown good outcome although long-term
follow up is not available.

13. • A majority of such studies have shown reductions in blood
pressure levels and in the need for antihypertensive
medications, with various effects on regression of left
ventricular hypertrophy.
• Health-related quality-of-life measures appear to improve
with frequent dialysis treatments.
• Results for measures of anemia control and calcium
phosphate metabolism show a mixed response

14. RATIONALE OF FREQUENT HEMODIALYSIS
• Blood solute concentrations and water/sodium
retention rise or fall irregularly in conventional thrice
weekly Hemodialysis, with peak values being
recorded before each HD session (particularly before
the first HD session of the week) and low values at
the end.

15. • This non physiological condition can be potentially associated with:
(as described by Locatelli et al).
• Peak concentration toxicity e.g. hyperkalaemia peaks and/or
pulmonary oedema can be lethal.
• Disequilibrium syndrome: due to sudden removal of urea and
sodium, manifesting mainly as headache and post-dialysis fatigue.
• Intra-HD hypotensive episodes: due to abrupt blood volume
reduction.
• Triggering of cardiac arrhythmias due to rapid electrolyte blood
concentration changes (particularly regarding potassium).

16. Various studies can be quoted showing benefits
of frequent hemodialysis.

19. CONCLUSION
• Frequent Hemodialysis can be considered as a very
useful procedure which can replace the conventional
dialysis frequency to improve outcome but is not
feasible economically and organizationally,
• Hence an alternative like dialysis every alternate day
can be followed to improve hemodynamic and
electrolyte stability which would mean just one
dialysis procedure extra fortnightly which is feasible.
• Such a study has not been done so far.

20. Thank you