The relationship between ultrafiltrate volume with icodextrin and peritoneal transport pattern according to the peritoneal equilibration test.
OBJECTIVE
To establish a relationship between peritoneal transport membrane pattern, analyzed by the peritoneal equilibration test (PET), and drained volume using icodextrin (7.5% Ico) and glucose (3.86% Glu) solutions.


METHODS
Thirty peritoneal dialysis patients were submitted to a standard 4-hour PET and divided into 4 transport categories based on dialysate-to-plasma ratio of creatinine (D/Pcr) and dialysate ratio of glucose at 4 and zero hours of the dwell (D4/D0). Patients were asked to perform exchanges for 2 consecutive nights in 10-hour dwells (2 L 3.86% Glu solution on the first night, and 2 L 7.5% Ico solution on the second night). The drained volume was measured and dialysate samples from the overnight exchanges were obtained for beta2-microglobulin (B2M) levels.


RESULTS
PET classification using D/Pcr showed that 46.6% of the patients were high and high-average transporters, or 23.3% when D4/D0 was used. In spite of this difference, both methods showed significant correlation (p = 0.0001, r = 0.862). The mean drained volumes were similar for both solutions (for 3.86% Glu, 2696 +/- 369 mL; for 7.5% Ico, 2654 +/- 424 mL). The high and high-average transport patients classified by D4/D0 achieved a higher ultrafiltration with 7.5% Ico than with 3.86% Glu (p = 0.0235). When classified by D/Pcr, the difference was not significant (p = 0.2243). In the low and low-average transport patients classified by D/Pcr, we observed a significantly lower ultrafiltration when 7.5% Ico was used compared to 3.86% Glu solution (p = 0.0197). Using D4/D0, we saw a tendency toward lower ultrafiltration (p = 0.0719) in the same group. We then correlated the PET results and the difference between drained volume with 7.5% Ico and 3.86% Glu solution [deltaV (I-G)]. We found a significant negative correlation between D4/D0 and deltaV (I-G) (p = 0.002, r = -0.5390), and a positive correlation between D/Pcr and deltaV (I-G) (p = 0.005, r = 0.4932). The levels of B2M obtained with 7.5% Ico were higher than those obtained with 3.86% Glu solution (for 7.5% Ico, 9.47 +/- 6.71 microg/vol; for 3.86% Glu, 7.29 +/- 4.91 microg/vol; p = 0.004). Furthermore, we found significant correlation between the total amount of B2M obtained with 7.5% Ico solution and D4/D0 (p < 0.0001, r = -0.4493), and D/Pcr (p < 0.0001, r = 0.5431).


CONCLUSIONS
Mean drained volume was similar between the two solution groups. High transporters, as defined by D4/D0, achieved higher ultrafiltration with 7.5% Ico than with 3.86% Glu solution. This is most likely due to the higher number of small pores in the peritoneal membrane. Low transporters, as classified by D/Pcr, achieved lower ultrafiltration with 7.5% Ico than with 3.86% Glu solution. The deltaV (I-G) and the PET results showed significant correlation, confirming that high transporters have a higher ultrafiltration volume with 7.5% Ico. The total B2M mass obtained with 7.5% Ico was greater than with 3.86% Glu solution and significantly higher in the high transport patients, indicating a larger number of small pores. Thus, the deltaV (I-G) could give us an idea of the peritoneal transport pattern in peritoneal dialysis patients.
Araújo Teixeira
Maria Regina
MR
Nephrology Division, Hospital das Clinicas, University of São Paulo, São Paulo, Brazil. marea@uol.com.br
Pecoits-Filho
Roberto Flávio Silva
RF
Romão Junior
João Egidio
JE
Sabbaga
Emil
E
Marcondes
Marcello Machado
MM
Abensur
Hugo
H
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001692:Biological Transport; D003404:Creatinine / Q000378:metabolism; D015314:Dialysis Solutions / Q000737:chemistry; D005260:Female; D005936:Glucans; D005947:Glucose; D006801:Humans; D000077607:Icodextrin; D008297:Male; D008875:Middle Aged; D010530:Peritoneal Dialysis; D010537:Peritoneum / Q000378:metabolism*; D001613:beta 2-Microglobulin / Q000032:analysis
D015314:Dialysis Solutions; D005936:Glucans; D001613:beta 2-Microglobulin; D000077607:Icodextrin; D003404:Creatinine; D005947:Glucose