Influence of the solution used for the long dwell on the results of the Peritoneal Equilibration Test using 3.86% glucose in CAPD.

Membrane characteristics are of great importance for the success of peritoneal
dialysis (PD). Every 6 months the transport properties of the peritoneal
membrane are measured to characterize the functional status of the membrane by
a peritoneal equilibration test (PET), both in terms of solute transport, and
fluid removal (ultrafiltration). Point of concern has been the influence of the
preceding dwell on the PET results. The last decade there is a growing use of
the glucose polymer icodextrin as dialysis solution ( by an estimated 50%).
Since icodextrin induces ultrafiltration by colloid osmosis through the small
pores of the peritoneal membrane, it is especially effective during long dwell
times. In a previous study by Lilaj et al. the results of a PET, performed with
2.27% glucose after a preceding dwell (10 hours) with 1.36% glucose was
compared with a 2.27% glucose PET after a preceding dwell (10 hours) with
icodextrin. Significant differences were observed for D/P creatinine, phosphate
and sodium, which were all greater after the icodextrin dwell. This could be
explained by existence of a residual volume that still contained icodextrin and
thereby could have lead to an additional convective transport of small solutes.
As an alternative explanation the authors proposed that the different solutions
might have different vasoactive effects on the peritoneal membrane, modulated
by the release of cytokines. However, no differences in mass transport area
coefficients (MTAC) of small solutes were reported.
Recently the ISPD has proposed to perform the PET with a 3.86% glucose solution
in stead of 2.27% glucose solution as was done in the study by Lilaj et al. No
information is available on the effect of the preceding night dwell on net
ultrafiltration using the advised 3.86% glucose solution or icodextrin before
the PET. Also the possible influence of the advised 3.86% glucose solution or
icodextrin as preceding exchange on free water transport, estimated using the
maximum dip in D/P sodium (sodium sieving) in the first phase of the dwell, has
not been examined before. Hypertonic glucose concentrations could also
influence the vascular reactivity and consequently decrease the difference in
transport characteristics with icodextrin.
In this study, the influence of the preceding nightdwell (3.86% glucose
solution = standard) on the results of the 3.86% PET will be compared to the
influence of icodextrin as preceding night dwell and with 2.27% glucose
solution (world wide most used as preceding dwell).
The practical consequence of this study is that, in case of equivalence between
the dialysis solutions, patients who already use icodextrin for their standard
treatment during nighttime, can continue this solution also in preparation for
the PET, which will make the preparation phase easier for the patient.

The aim of the present study is to compare the following transport
characteristics for a modified 3.86% glucose PET preceded by a long (>8 hours)
dwell with 3.86% glucose (PET A) and one preceded by a long dwell with 7.5%
icodextrin (PET B), and a third PET preceded with 2.27% glucose solution (PET
C):
1. Small solute transport (including a characterization into a transport group)
2. Net ultrafiltration (= fluid removal)
3. Sodium sieving and free water transport

In 20 stable patients on CAPD we will perform two standardized 3.86% glucose
PETs (duration 4 hours) in random order (with sealed envelopes) within 2 weeks.
One test will be preceded by a preceding night dwell of 8 to 12 hours with a
standarized 3.86% glucose solution (PET A). The other PETs will be performed
after a preceding night dwell of 8 to 12 hours using a glucose polymer solution
(icodextrin) (PET B) and 2.27% glucose solution (PET C).
In all tests characterization, small solute transport (D/P creatinine and urea,
Dt/D0 glucose, MTACcreatinine and urea), sodium sieving (dip D/P sodium after 2
hours) with calculation of free water transport and net ultrafiltration will be
achieved.

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There are no risks for the patients. In this study patients will use another
regularly used dialysate fluid (icodextrin or 2.27% glucose) in state of the
3.86% glucose solution as preceding night dwell before perfomance of the PET.
Ultrafiltration (fluid removal) is basically not different between the standard
procedure (3.86% gluoces solution) and icodextrin.
There are no direct benefits for the patients.