Determination of Individual Ultrafiltration Time (Apex) and Purification Phosphate Time by Peritoneal Equilibration Test: Application to Individual Peritoneal Dialysis Modality Prescription in Children

Abstract

Efficiency of peritoneal dialysis (PD) is dependent on adequate ultrafiltration (UF) and purification (solute clearance). These two goals apparently seem to conflict in terms of duration of dwells: short dwell time enhances UF capacity and, conversely, long dwell time enhances solute clearance. Peritoneal equilibration test (PET) allows an approach to the ultrafiltration time: the point at which the over time dialysate urea saturation and glucose desaturation curves cross, called APEX time. PET also allows an approach to the purification time: the point at which dialysate-to-plasma (DIP) concentration ratios over time are high. Because of the value of phosphate as a uremic factor of morbidity, we have chosen the time at which DIP phosphate is equal to 0.6 as a purification phosphate dwell time (PPT). A total of 17 patients were studied, over a five-year period, allowing 142 determinations. APEX times (range 18 71 min) and PPT (range 105 -238 min) were spread over a wide distribution. PPT and APEX times were significantly shorter in children younger than three years of age than in children older than ten years of age. PPT were nearly four times longer than APEX times. Knowledge of these conflicting ultrafiltration and purification times should help, in our view, in the individual choice of the PD modality: if UF is the major goal, short dwell times should be used (automated PD); if purification is the major goal, long dwell times should be used, as in continuous ambulatory peritoneal dialysis; if both are the target goal, tidal PD should be discussed.

Increasing sodium removal on peritoneal dialysis: applying dialysis mechanics to the peritoneal dialysis prescription

“…Nevertheless, a prescription characterized by a fixed dwell time or fixed dwell volume throughout the PD treatment may not optimally meet individual patient needs. 13,17,28 APD efficiency in terms of sodium and water removal may be improved by an individually adapted prescription as proposed in A-APD, a novel approach to the performance of APD in which the above-mentioned peritoneal solute and water transport mechanisms are incorporated into the prescription process. 17,28,29 The A-APD procedure (Figure 3) consists of 2 different sequences of exchanges during a single PD session.…”

“…Both the dwell time and dwell volume are determined for each patient individually: the dwell volume is prescribed in milliliters per meter squared body surface area and the dwell time is determined based on the patient's membrane transport characteristics. 1,17,28 A-APD sequences are applied using the same total amount of dialysate and the same total therapy time as for conventional APD based on clinical needs and the same total amount of prescribed glucose, same glucose dialysate concentration. 29 The short dwell time in A-APD may be determined according to the transporter status obtained from the peritoneal equilibrium test, or directly assessed from the crossing time point of the glucose (D/D0) and urea (D/P) curves on the peritoneal equilibrium test, the so-called APEX (accelerated peritoneal examination) time.…”

Adaptuota Automatinė Peritoninė Dializė: Užpylimo Tūrio Ir Ekspozicijos Laiko Varijavimo Svarba

“…To avoid hyperhidration which is known as a risk factor for cardiovascular complications [2,3,5] we should use short time dwells. On the over hand such a choice is inappropriate for adequate purification of creatinine and phosphates [6,21] and may induce positive sodium balance [22]. Long-dwell exchanges allow for more nitrogenous waist products that need longer diffusion time clearance [7,22].…”

“…On the over hand such a choice is inappropriate for adequate purification of creatinine and phosphates [6,21] and may induce positive sodium balance [22]. Long-dwell exchanges allow for more nitrogenous waist products that need longer diffusion time clearance [7,22]. However too long-dwell is a risk factor for decreased UF and does not appreciably improve urea removal [7].…”

“…As UF, blood purification and dialysate reabsorption capacities are individual for every patient peritoneal equilibration test (PET) needs to be performed [5,6,7]. It allows determining individual permeability parameters (APEX time; phosphate purification time) and enables to adapt dwell time to the patient's condition and treatment targets [1,22].…”