Icodextrin Simplifies Pd Therapy by Equalizing Uf and Sodium Removal among Patient Transport Types during Long Dwells: A Modeling Study

Abstract

♦ Background: In recent years, results from clinical studies have changed the focus of peritoneal dialysis (PD) adequacy from small solute clearance to volume control, resulting in continued efforts to improve fluid and sodium removal in PD patients. We used a modified 3-pore model to theoretically predict fluid and solute removal using glucose-based and icodextrin solutions for a wide range of transport characteristics with automated PD (APD) and continuous ambulatory PD (CAPD) therapies. ♦ Methods: Simulations were performed for the day (APD: 15-hr, 2.27% glucose and 7.5% icodextrin; CAPD: 3x5-hr, 1.36% and 2.27% glucose) and night (APD: 9-hr, 1.36% glucose; CAPD: 9-hr, 2.27% glucose and 7.5% icodextrin) dialysis periods separately. During APD, the number of night exchanges (N) was varied from 3 to 7. Ultrafiltration (UF), sodium removal (NaR), total carbohydrate absorption (CHO), UF efficiency (UFE), and sodium removal efficiency (NaRE) were calculated. Typical patients in fast (i.e. high, H), average (high-average, HA; low-average, LA), and slow (low, L) transport groups with no residual kidney function were considered. ♦ Results: The effective dwell times varied between 1.0 and 14.7 hours depending on the number of exchanges. With glucose-based solutions, differences in UF and NaR between H and L transport patients ranged from 140 mL and 2 mmol (APD night, n = 7) to 778 mL and 56.4 mmol (CAPD day, 2.27%). With icodextrin, differences in UF and NaR ranged from 1 mL and 1.1 mmol (CAPD night) to 59 mL and 6.1 mmol (APD day). The use of icodextrin resulted in greater CHO than 2.27% glucose (APD: 27.1 -35.6 g more; CAPD: 17.1 -17.5 g more). The UFE and NaRE were greater for all patients with icodextrin than with glucose-based solution in both therapy modalities, except for slow transport patients in CAPD. ♦ Conclusion: This modeling study shows that the dependence of UF and NaR on patient transport type observed with glucose-based solutions can be minimized using icodextrin during the long dwells of APD and CAPD. While this approach simplifies the PD prescription by minimizing the dependencies of ultrafiltration and sodium removal on patient transport type when using icodextrin, it improves fluid and sodium removal efficiencies in fast and average transport patients without any added glucose exposure.

Volume-Based Peritoneal Dialysis Prescription Guide to Achieve Adequacy Targets

“…Conversely, glucose-based PD solutions not only become iso-osmolar compared with plasma over time as glucose is absorbed across peritoneal capillaries, but a large portion of the ultrafiltrate obtained is devoid of solute resulting from the action of these solutions on peritoneal capillary aquaporins. The contrasting mechanisms of these osmotic agents ensure that volume removal using icodextrin will also remove more sodium than the same UF volume when using glucose-based solutions (29,30).…”

“…PET category); Table 2 shows the detailed characteristics of patients within these groups. Several representative summaries of peritoneal fluid and solute transport parameters derived from the TARGET study, including those assumed for icodextrin fractions, have been previously published (28)(29)(30).…”

Single Daily Icodextrin Exchange as Initial and Solitary Therapy

“…This might compromise both UF and solute removal for either daytime or nighttime treatment, potentially precluding the convenience of "incremental" continuous ambulatory PD nighttime exchanges altogether. Conversely, icodextrin is limited neither by membrane transport nor by extended dwell time, typically producing similar UF and solute removal irrespective of membrane transport type, and allowing dwell times of 8 to 16 hours (18,31). Application of a solitary exchange of icodextrin as the nidus of incremental PD might therefore not only simplify the initial PD prescription for incident patients with RRF and their providers, but might further lessen the procedural burden, as well as infectious and metabolic risks inherent to PD therapy.…”

Evaluating Hyponatremia in Non-Diabetic Uremic Patients on Peritoneal Dialysis

“…For type III hyponatremia due to a high peritoneal membrane transporter and low UF rate, modification of dialysis modality is the cornerstone of management because this type of hyponatremia is an epiphenomenon. Icodextrin-based dialysate could be the dialysate of choice if PD is continued (30). Switching to hemodialysis or renal transplantation may be the management of choice if PD is discontinued.…”