Increasing the Dialysis Volume and Frequency in a Fixed Period of Time in CPD Patients: The Effect on Kpt/V and Creatinine Clearance

Abstract

Background The National Kidney Foundation Kidney Disease Outcomes Quality Initiative (K/DOQI) has evidence- and opinion-based recommendations for weekly Kt/Vurea and weekly total creatinine clearance (CC) in chronic peritoneal dialysis (CPD) patients. Using standard continuous ambulatory peritoneal dialysis technique, it is often difficult to achieve the suggested targets in anuric patients with large body mass. Thus, the use of automated peritoneal dialysis (APD) has been increasingly utilized to achieve adequate clearances. Automated dialysis is usually performed at night over an 8- to 10-hour period. The role of increases in dialysate volume and frequency of exchanges during this time period to achieve these target K/DOQI recommendations remains uncertain. We decided to study the effects of increasing the volume and number of exchanges in a fixed period of time in CPD patients. Methods In the New Haven CAPD unit, 29 patients maintained on APD were considered eligible for the study and 11 agreed to participate. The patients were characterized according to standard peritoneal equilibration test criteria. The patients were placed into two groups: group 1 included high (H) and high-average (HA), and group 2 low-average (LA) transporters. The patients were dialyzed at night for 9 hours with standard cycling technique, using 2.5% Dianeal (Baxter Healthcare, Deerfield, Illinois, USA) solution, with a cycle volume of 2500 mL, and a 2000-mL daytime dwell. Three studies were done on each patient using a total dialysis volume of 9.5 L (3 cycles), 14.5 L (5 cycles), and 19.5 L (7 cycles). Daily Kpt/Vurea and daily CCp (peritoneal) (L/day/1.73 m2) were obtained. Results Six patients were H or HA (group 1) and 5 were LA transporters (group 2). For the group 1 patients, mean weight was 86.6 ± 13.5 kg; Kpt/Vurea was 1.68 ± 0.21 using 9.5 L, 2.03 ± 0.28 for 14.5 L ( p < 0.05 compared to 10 L), and 2.28 ± 0.28 with 19.5 L ( p < 0.05 compared to 10 L and 15 L); mean weekly CCp was 45.43 ± 7.63 L/1.73 m2 for 9.5 L ( p < 0.05 compared to 14.5 L and 19.5 L), 51.17 ± 7.07 with 14.5 L, and 54.67 ± 10.08 for 19.5 L; ultrafiltration rates were not different in the three studies. For the group 2 patients, mean weight was 74.3 ± 17.7 kg; mean weekly Kpt/Vurea was 1.68 ± 0.35 using 9.5 L, 2.10 ± 0.42 for 14.5 L ( p < 0.05 compared to 9.5 L), and 2.31 ± 0.56 for 19.5 L ( p < 0.05 compared to 9.5 L and 14.5 L); mean weekly CCp was 42.56 ± 10.64 L/1.73 m2 for 9.5 L ( p < 0.05 compared to 14.5 L and 19.5 L), 50.89 ± 12.66 for 14.5 L, and 51.94 ± 11.20 for 19.5 L; ultrafiltration was lower in the 9.5-L study than in the 14.5-L and 19.5-L studies, but was not different in the 14.5-L and 19.5-L studies. Conclusions In both H/HA and LA transporters, Kpt/Vurea and CCp rise significantly when the frequency of exchanges and total volume of dialysate are increased. Thus, the use of larger volumes of dialysate with cycling peritoneal dialysis may result in increased clearances of urea and creatinine.

Renal Replacement Therapy: Purifying Efficiency of Automated Peritoneal Dialysis in Diabetic versus Non-Diabetic Patients

“…Probably, in our opinion, based on the rule that an increasing small-solute clearance and therefore, a better adequate dialysis dose and control of water balance and salt, has a significant impact on the clinical course. Increased small solute clearance in PD is mainly achieved by increasing the fill volume and the number of exchange, and this is only possible with automated techniques [ 25 , 26 , 27 ].…”

Peritonitis and Automated Peritoneal Dialysis: A Therapeutic Conundrum?

“…The increased use of cycler therapy has occurred for several reasons. Of particular importance are the concerns expressed about the dose of dialysis delivered to CPD patients with standard ambulatory CPD (CAPD) therapy and the observation that both urea and creatinine clearances can be increased with cycler therapy (13). Furthermore, the development of new, more efficient cyclers has facilitated CPD therapy and improved patients’ perception of the therapy by eliminating or minimizing the need for daytime exchanges.…”