Lam G, Kovithavongs C, Ulan R, Kjellstrand C
Sodium ramping in hemodialysis only removes side-effects from
one time period to another
42nd Annual Conference of the ASAIO
ASAIO J
(May) 42:(2):76 1996
The benefits of ramped sodium dialysis remain controversial. We recently
reviewed a
paper by Goldstein et al
on HDCN on this subject. In that paper, hypotension was not improved, but
symptoms were, and there
was no increased interdialytic weight gain. The latter was surprising to me,
as the postdialysis
sodiums were elevated using their 155-160 to 140 mM sodium ramp.
In the present abstract, Kjellstrand's group compared side effects in 296
patients undergoing 2
weeks of each of three sodium profiles: steady 140 mM, ramped 150 to 140, and
stepped, 155 2 hours
followed by 140 2 hours. Noteworthy is the fact that in each of these
protocols, the "time
averaged" dialysate sodium is greater than 140, so they all should increase
positive sodium balance,
unless there is a greater net ultrafiltration to compensate for the increased
diffusive sodium
transfer.
The results were slightly different from those in Goldstein's study. There
was no improvement in
headache, nausea, or vomiting, the so-called disequilibrium group of
symptoms. However, there was
an overall improvement in total side effects, cramping, and hypotensive
episodes with both the ramp
and step protocols. On the dark side, interdialytic thirst and weight gain
increased, as did
fatigue, and there was an increase in blood pressure.
Comment: I remain skeptical of the benefits of ramped sodium dialysis.
There is benefit in
raising dialysate sodium, but the cost is increased interdialytic weight gain
in most circumstances.
We were among the first to report an evaluation of ramped sodium dialysis in
the 1980s, and all
patients, using a 160/130 ramp, had increased interdialytic weight gain. I
continue to believe
ramping to be useful for patients with cramps. I also think that ramping
does not make sense unless
combined with a non-linear UF rate. This may account for the variability in
some studies.
Having said this, there was a related abstract presented at this ASAIO
meeting by Khairullah and
Flanigan, where they compared 140 mM fixed sodium with a stepped protocol
using an exponential
decrease from 155 to 135 mM sodium (abstract on page 83 of the above issue of
the ASAIO J). UF was
accelerated during early dialysis and was zero during the last 30 minutes.
They
found no increase in interdialytic weight gain, but also no difference in
symptoms, and a
decreased need for anti-hypertensive medications. So in summary,
different people get
different results with ramped sodium dialysis. In this patient population
where LVH and volume
overload appear to contribute to mortality, I believe that patients should
not be salt loaded during
dialysis without good reason. I would like to see a comparison of a ramping
protocol that included
variable UF, and where the time averaged dialysate sodium concentrations are
equal.
(John T. Daugirdas, M.D., University of Illinois at Chicago)
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