Advances in Peritoneal Dialysis, Vol. 13, 1997
Variability of Peritoneal
Equilibration Test in Children
on Continuous Peritoneal
Dialysis By Repeated Testing
With Solutions of Different
Christiane Laux, Klaus-Eugen Bonzel, Friederike Rubbert- Osmolarity
Lauterbach, Rainer Biischer, Anne-Margret Wingen
To evaluate (1) differences in the peritoneal equilibration test Key words
(PET) achieved using continuous peritoneal dialysis (CPD) Peritoneal dialysis in children, peritoneal equilibration test,
solutions containing d~ ferent amounts of glucose and (2) intra dialysis fluid, glucose content in dialysis fluid
individual reproducibility of PEn performed twice within an in-
terval of 8 months on CPD, we investigated 39 PETs in 13 Introduction
children aged 2.4-19.0years (median 10.6 years) on stable CPD A standardized peritoneal equilibration test (PET) has been used
regimens. The fill volume was 1 L/ml body surface area. We used in continuous peritoneal dialysis (CPD) patients since 1986 to
a standard CPD solution (Fresenius) with a 2.3% glucose content evaluate peritoneal transport kinetics (1,2). Later, the PET was
(groups 2.3a and 2.3b) two times within an interval of 1 -8 adapted for study in children (3-5), and reference values for
months. A third test was done between the two with a children were developed (6).
CPDsolution ofl.5%glucose (group 1.5). Equilibration quotients,
that is, substrate concentration in dialysis fluid divided by
substrate concentration in plasma (D/P), did not show any Subjects
statistically significant differences between groups 1.5 and 2.3a Thirteen children (8 boys, 5 girls) on stable CPO were studied.
or between groups 2.3a and 2.3b. A significant d~ ference was The patients' age ranged between 2.4 and 19.0 years (median
seen in the decline of glucose content of dialysate between groups 10.6 years). Underlying renal diseases were congenital in 5
1.5 and 2.3 but not between groups 2.3a and 2.3b. Ultrafiltration patients (dysplasia in 2, prunebelly syndrome in 1, nephrotic
was higher in groups 2.3a and 2.3b compared with group 1.5. In- syndrome in I, and nephrocalcinosis in I) and acquired in 8 cases
ter and intraindividual variability between solute transfer was (different kinds of glomerulonephritis in 6, hemolytic uremic
small during follow-up in stable CPD patients. Different glucose syndrome in 1, and shock in I ). Total number of PETs was 39;
contents of 1.5 and 2.3 g/dL dialysis fluid had no measurable 15 were performed on patients on continuous ambulatory
influence on PET results of stable CPD patients. For standard peritoneal dialysis (CAPD) and 24 on patients on continuous
PETs, reducing the glucose content of dialysis fluid to iso- cyclic peritoneal dialysis (CCPD). Mean time on CPO was 22.4
osmolarity is not necessary. months at the first, 24.0 at the second, and 28.5 months at the
third PET. At time of testing all patients were free from
peritonitis (at least 4 weeks after termination of antibiotic
treatment). Three patients suffered from peritonitis during
From: Department of Pediatric Nephrology, Universitiits- The PET was performed in the morning after an overnight dwell
kinderklinik Essen, Germany. by CAPO or a usual nighttime exchange
264 Laux et al.
regimen in CCPD patients. After a complete drainage, the
peritoneal cavity was filled with I Llm2 body surface area
of solution. We used a commercially available CPD
solution (Fresenius) containing 1.5% (group 1.5) and
2.3% (group 2.3) glucose. The first and the third PETs
were done with standard CPD solution containing 2.3%
(groups 2.3a and 2.3b) within an interval of I -8 months,
and the second PET was performed with CPD solution
containing 1.5% glucose (group 1.5) between the others.
Glucose, volume, potassium, urea, creatinine, and
phosphorus were measured in dialysate (D) six times
during a 6-hour dwell by a complete drainage technique
and in plasma (P) two times (dwell time 0 and 4). The
concentrations of glucose, urea, and phosphorus
(enzymatic reactions), creatinine (modified Jaffe reaction,
corrected for glucose concentration in dialysate ), and
potassium (ion-selective electrode method) were de-
termined in each dialysate and plasma sample (6). For
each patient at each dwell time DIP was calculated for
urea, phosphorus, creatinine, and potassium, D t ID o for high and high-average transporters up to 70% (5). This is
glucose, and V t N o for ultrafiltration. All data are given in agreement with our findings (not shown here). But the
as mean:1:SD. Student's t-test for paired data was used variability ofPET results in the literature is rather large.
for statistical evaluation. The results are considered By selecting patients strictly according to stable clinical
statistically significant for p < 0.01. conditions without signs of active peritonitis, we found an
interindividual variance much smaller than shown before
(5,6). In contrast to our previous data, intra individual
Results variance was also small, if short time influences near a
Different glucose contents of dialysis fluid of 2.3% and preceding episode of peritonitis were excluded. Glucose
1.5% glucose do not influence PET results in stable CPD resorption profiles of our follow-up only hint at increasing
patients (Table I). This is even more important when permeability of the peritoneal membrane by time. But loss
realizing the small inter and intraindividual variance of ultrafiltration was not detectable in the absence of
ofPET results. Also, repeated testing of all patients after I peritonitis. Unlike others (7), we did not observe a
-8 months showed intraindividually stable equilibration decrease in DIP creatinine following peritonitis, albeit 6
curves even after a cured intercurrent peritonitis episode of our 13 patients had between one and four episodes of
(Figure I ). In 2 of the 3 patients who developed peritonitis before the tests, and 3 patients each had one
peritonitis between the tests, PETs after one month episode during the test. We know that our follow-up time
showed steeper equilibration curves for potassium and was somewhat short. We think that even repeated
phosphorus, which reversed later on (Figure 2). DIP of episodes of peritonitis will not necessarily influence
urea always showed the steepest curves and was never in- peritoneal function in a negative way, if the intervals
fluenced by peritonitis. between episodes of peritonitis are long enough and
healing is complete. Two of the 3 patients with peritonitis
between the tests and who underwent PETs one month
Discussion after peritonitis was cured showed a reversible increase in
CPD is an extensively used dialysis method in children. DIP values for potassium and phosphorus. Variability of
Peritoneal membrane mass transfer is both diffusive and PETs seems to be much smaller than expected and not
convective. The considerable individual variability in the detectable by changing the osmolarity of dialysis fluid.
handling of different solutes is well known (6). The Therefore, the PET can be
experience with pediatric PET curves differed from those
in adults by showing many more
Laux et at.
performed with reasonable accuracy, without reducing the dialysis. Toronto: Peritoneal Dialysis Bulletin, 1991;
glucose content of dialysis fluid to isoosmolarity. The 7:262-5.
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Ruddley J. The peritoneal equilibration test in children.
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Kidney Int 1992; 42:102~5.
6 Schaefer F, Langenbeck D, Heckert, KH, Schiirer K, Mehls
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