Peritoneal.equilibrium test with icodextrin and glucose dialysates

The aim of this study was to compare, under standard conditions (Peritoneal Equilibrium Test, (PET)), the peritoneal permeability to water and several soutes using icodextrin and glucose (3.86% and 1.36%) dialysates. The study includes 14 patients (3 women and 11 men), mean age 64+/-13 years, average time on peritoneal dialysis 23.5+/-17 months. PETS with icodextrin were performed in all of them (n=14); PETS with 3.86% glucose were carried out in 7, and PETS with all the three solutions were performed in 5 patients. Samples were taken at 0, 30, 60, 120, 240 minutes, and after the rinsing procedure using 1.36% glucose in order to calculate the residual volume. Results: Sodium concentration in the effluent and D/P sodium did not change significantly from minute 0 to 240 with icodextrin and 1,36% glucose; but with 3.86% glucose both sodium and D/P sodium decreased at thirty minutes, remained at the same levels till the 120 minutes and then had a tendency to increase. Glucose concentration and osmolarity in the effluent did not vary throughout the time with icodextrin, but progressively decreased during the 4-hour period with 3.86% and 1.36% glucose solutions. The drainage after the 4-hour period was higher for the 3.86% glucose (2,608+/-388 ml, p=0,03) than for the 1.36% glucose (2,070 120 ml) or the icodextrin (2,212+/-213 ml). Low molecular weight permeability: D/P creatinine after the 4-hour dwell was significantly lower for the icodextrin (0.66+/-0.1, p=0,05) than for the 3.86% glucose (0.71+/-0.1) or the 1.36% glucose (0.72+/-0.1). The creatinine clearance for 3.86% glucose (7.4+/-0.4 ml/min p=0.007) was higher than for icodextrin (5.6+/-0.5 ml/min) or for 1.36% glucose (5.8+/-0.6 ml/min). The clearances for total protein, albumin and beta(2)-microglobulin did not show significant differences between the solutions. Conclusions: Our study confirms that the icodextrin solution remains isoosmolar with plasma during the 4-hour dwell. The sodium profile suggests that the ultrafiltration induced by icodextrin and 1.36% glucose depends on small pore-mediated sodium and water transport; on the other hand, 3.86% glucose also induces transport of water without solutes throughout the ultrasmall aquaporin-mediated, pores, producing sodium dilution in the effluent. Ultrafiltration and solute clearances for icodextrin are lower than for 3.86 glucose during a 4-hour dwell.