Intermittent Peritoneal Dialysis: Urea Kinetic Modeling and Implications of Residual Kidney Function

Abstract

♦ Background: Intermittent peritoneal dialysis (IPD) is an old strategy that has generally been eclipsed, in the home setting, by daily peritoneal therapies. However, for a select group of patients with exhausted vascular access or inability to receive PD at home, in-center IPD may remain an option or may serve as an incremental strategy before initiation of full-dose PD. We investigated the residual kidney clearance requirements necessary to allow thrice-weekly IPD regimens to meet current adequacy targets. ♦ Methods: The 3-pore model of peritoneal transport was used to examine 2 thrice-weekly IPD dialysis modalities: 5 -6 dwells with 10 -12 L total volume (low-dose IPD), and 50% tidal with 20 -24 L total volume (high-dose IPD). We assumed an 8-hour dialysis duration and 1.5% dextrose solution, with a 2-L fill volume, except in tidal mode. The PD Adequest application (version 2.0: Baxter Healthcare Corporation, Deerfield, IL, USA) and typical patient kinetic parameters derived from a large dataset [data on file from Treatment Adequacy Review for Gaining Enhanced Therapy (Baxter Healthcare Corporation)] were used to model urea clearances. The minimum glomerular filtration rate (GFR) required to achieve a total weekly urea Kt/V of 1.7 was calculated. ♦ Results: In the absence of any dialysis, the minimum residual GFR necessary to achieve a weekly urea Kt/V of 1.7 was 9.7 mL/min/1.73 m 2 . Depending on membrane transport type, the low-dose IPD modality met urea clearance targets for patients with a GFR between 6.0 mL/ min/1.73 m 2 and 7.6 mL/min/1.73 m 2 . Similarly, the high-dose IPD modality met the urea clearance target for patients with a GFR between 4.7 mL/min/1.73 m 2 and 6.5 mL/min/1.73 m 2 . ♦ Conclusions: In patients with residual GFR of at least 7.6 mL/min/1.73 m 2 , thrice-weekly low-dose IPD (10 L) achieved a Kt/V urea of 1.7 across all transport types. Increasing the IPD volume resulted in a decreased residual GFR requirement of 4.7 mL/min/1.73 m 2 (24 L, 50% tidal). In patients with residual kidney function and dietary compliance, IPD may be a viable strategy in certain clinical situations.

Predicting the Peritoneal Absorption of Icodextrin in Rats and Humans Including the Effect of α–Amylase Activity in Dialysate

“…1.7 < BSA < 2.1 m 2 ) were considered. Details of the dataset from which these four patients were derived and the procedure followed to estimate patient-specific model parameters have been described elsewhere (4,16,18). The reflection coefficients (σs) and MTACs for the modeled icodextrin MW fractions were calculated using the standard threepore theory (1,19).…”

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

“…As previously described in several similar modeling studies (20,21), the data were first grouped in 4 peritoneal equilibration test (PET) categories (high: H, high-average: HA, low-average: LA, low: L) according to 4-hour dialysate/plasma (D/P) creatinine measurements (22). To be consistent with the nature of solute transport across the peritoneal membrane, we will refer to these groups in this report as fast (H), average (HA and LA) and slow (L) peritoneal transport groups, unless specific reference to 1 of the 4 PET categories is needed.…”

A mathematical model for fluid-glucose-albumin transport in peritoneal dialysis

“…The mathematical descriptions of these systems were obtained using partial differential equations based on the simplification that capillaries are homogeneously distributed within the tissue. Experimental evidence confirmed the good applicability of such models (see, for example, the papers of Waniewski et al (1996a;1996b;2007), Smit et al (2004a), Flessner (2006), Parikova et al (2006), Stachowska-Pietka et al (2012), Guest et al (2012) and the references therein).…”