Peritoneal Dialysis International, Vol. 30, pp. 633–637 doi:10.3747/pdi.2009.00038 0896-8608/10 $3.00 + .00 Copyright © 2010 International Society for Peritoneal Dialysis 633 EFFICACY OF PERITONEAL DIALYSIS DURING INFUSION AND DRAINAGE PROCEDURES Daniel Baczyn´ski, 1 Stefan Antosiewicz, 1 Jacek Waniewski, 2 Zbigniew Nowak, 1 and Zofia Wan ´kowicz 1 Department of Internal Medicine, Nephrology and Dialysis Therapy, 1 Military Institute of Medicine; Institute of Biocybernetics and Biomedical Engineering, 2 Warsaw, Poland Correspondence to: D. Baczyn´ski, Department of Internal Medicine, Nephrology and Dialysis Therapy, Military Institute of Medicine, Ul. Szaserów 128, 04-141 Warsaw, Poland. dbaczynski@esculap.pl Received 19 February 2009; accepted 12 March 2010. ♦ Background: Inadequate dialysis is still a major cause of technique failure in peritoneal dialysis (PD). Mathemati- cal models provide the possibility of direct and precise as- sessment of peritoneal transport of urea and creatinine throughout the dwell and allow calculation of optimal schedules, dwell times, and predicted adequacy of a pre- scribed regimen. Kinetic modeling is particularly important for automated PD. If the effectiveness of uremic toxin re- moval that takes place during infusion and drainage of di- alysis fluid is not taken into account, the predicted adequacy of the whole PD session may be underestimated. ♦ Aims: To estimate the efficacy of urea and creatinine re- moval during the dialysis fluid exchange procedure. ♦ Material and Methods: 17 patients treated with PD were included in the study. PD effectiveness during dialysate ex- change was defined as the quotient k of removed amount of creatinine/BUN during the infusion and drainage of di- alysate and during a dwell of the same duration as the di- alysate exchange. ♦ Results: The effectiveness of creatinine and urea removal was reduced during the exchange procedure (k creat = 0.68 ± 0.43 and k BUN = 0.87 ± 0.44) and differed between these 2 solutes (p = 0.0009). The k coefficients for urea and creat- inine were well correlated (R 2 = 0.83). ♦ Conclusions: The effectiveness of peritoneal transport of creatinine and BUN during the inflow/outflow phase was relatively high compared to that during the same dwell time (68% and 87% respectively). This real effectiveness of the dialysate exchange procedure should be taken into account in the process of planning automated PD sessions, otherwise the predicted overall efficacy of creatinine and urea removal throughout the session may be underestimated. This under- estimation is proportional to the number of dwells per day. Perit Dial Int 2010; 30:633–637 www.PDIConnect.com epub ahead of print: 26 May 2010 doi:10.3747/pdi.2009.00038 KEY WORDS: Efficacy; adequacy; dialysate exchange. P eritoneal dialysis (PD) is an important option in renal replacement therapy. In many cases of vascular ac- cess failure or when hemodialysis is contraindicated, PD remains the only possible method of treatment. Apart from the inflammatory complications that are among the main causes of PD program failure, the key factors of pa- tient and technique survival are efficacy and adequacy (1). There are several clinical, biochemical, and kinetic criteria useful for the evaluation of PD adequacy (2). The analysis of peritoneal transport of small molecules, urea and creatinine in particular, is one of the main elements of adequacy assessment (3). The possibility of predict- ing the optimal PD schedule plays an important role in a PD program. Kinetic modeling can help to establish optimal dwell times and dialysis schedules. The characteristics of peritoneal transport allow us to calculate the predicted adequacy of a planned dwell, as expressed, for example, by Kt/V urea. The sum of Kt/V urea of particular dwells shows the predicted adequacy of the whole PD session; however, a simple “summing up” of the predicted ad- equacy parameters of particular dwells omits the im- portance of uremic toxin removal that takes place during the dialysis fluid infusion and drainage proce- dures. Thus, the adequacy of the whole PD session is underestimated. On the other hand, it should be con- sidered that the efficacy of dialysis during PD fluid ex- changes is lower than the effectiveness of the dwell when PD fluid is instilled in the peritoneal cavity. There- fore, it is necessary to evaluate the efficacy of the in- flow/outflow procedure. The difference in the efficacy of removal of particular uremic toxins should be con- sidered also, as underlined by several authors (4–6). However, the approach to the problem may be based on different premises. This effectiveness may be deter- mined as halved clearance during inflow/outflow This single copy is for your personal, non-commercial use only. For permission to reprint multiple copies or to order presentation-ready copies for distribution, contact Multimed Inc. at marketing@multi-med.com