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Choosing a modality for chronic peritoneal dialysis

John M Burkart, MD
Section Editor
Steve J Schwab, MD
Deputy Editor
Alice M Sheridan, MD


Several different techniques are available for performing peritoneal dialysis. Before discussing these modalities, it is helpful to briefly review the determinants of solute clearance with peritoneal dialysis. The rates (in mL/min) of peritoneal blood flow and dialysate flow with peritoneal dialysis are well below those achieved with hemodialysis (where both are often above 400 mL/min). Thus, the clearance of urea and other small solutes per unit time is much less with peritoneal dialysis than with hemodialysis. However, peritoneal dialysis is often performed in a continuous fashion so that the weekly solute clearances approach those with hemodialysis.

When discussing removal of solutes from the body by dialysis, we generally talk about two processes: diffusion and convection. It is important to appreciate that rates of diffusion for various solutes vary by molecular weight. The molecular weight for urea is very small, so urea rapidly diffuses into the peritoneal dialysate (which initially contains no urea) so that the average dialysate-to-plasma urea ratio is 0.7 at two hours and 0.9 at four hours. Comparable values for creatinine (a slightly larger molecule) are 0.45 and 0.65, respectively (figure 1); other larger molecular weight solutes diffuse much more slowly. Thus, urea and other small solutes are rapidly removed in the first few hours of a dwell; after four hours, there is very little further removal of small solutes due to near equilibration in concentrations. There is, however, continued removal of larger solutes, which do not equilibrate as rapidly.


Peritoneal dialysis can be performed in a continuous or intermittent fashion [1]. Continuous ambulatory peritoneal dialysis (CAPD) involves multiple exchanges during the day (usually three), followed by an overnight dwell. A modification involves one nighttime exchange with an exchange device, resulting in two overnight exchanges and three exchanges during the day [2]. There used to be a device designed specifically for this option (the nightly exchange device); however, this device is no longer available. As a result, this modification of CAPD is seldom used; when it is used, a standard cycler is required.

Automated peritoneal dialysis (APD) uses a cycler to perform multiple overnight exchanges. Modifications to this technique include continuous cycler peritoneal dialysis (CCPD), nightly intermittent peritoneal dialysis (NIPD), and tidal peritoneal dialysis (TPD) [3]:

CCPD has a long daytime dwell (typically called a "last bag fill" [LBF]) and several cycles overnight. A minority of patients undergoing CCPD do not have a daytime dwell ("dry day"), while some patients must also do a "midday exchange" (MDE) to meet adequacy or ultrafiltration targets [2].

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Literature review current through: Sep 2017. | This topic last updated: Sep 01, 2016.
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  1. Twardowski ZJ. Peritoneal dialysis glossary III. Perit Dial Int 1990; 10:173.
  2. Teitelbaum I, Burkart J. Peritoneal dialysis. Am J Kidney Dis 2003; 42:1082.
  3. Dell'Aquila R, Rodighiero MP, Spanó E, et al. Advances in the technology of automated, tidal, and continuous flow peritoneal dialysis. Perit Dial Int 2007; 27 Suppl 2:S130.
  4. Juergensen PH, Murphy AL, Pherson KA, et al. Tidal peritoneal dialysis to achieve comfort in chronic peritoneal dialysis patients. Adv Perit Dial 1999; 15:125.
  5. Juergensen PH, Murphy AL, Pherson KA, et al. Tidal peritoneal dialysis: comparison of different tidal regimens and automated peritoneal dialysis. Kidney Int 2000; 57:2603.
  6. Dombros N, Dratwa M, Feriani M, et al. European best practice guidelines for peritoneal dialysis. 2 The initiation of dialysis. Nephrol Dial Transplant 2005; 20 Suppl 9:ix3.
  7. Diaz-Buxo JA. Evolution of continuous flow peritoneal dialysis and the current state of the art. Semin Dial 2001; 14:373.
  8. Freida P, Issad B. Continuous flow peritoneal dialysis: assessment of fluid and solute removal in a high-flow model of "fresh dialysate single pass". Perit Dial Int 2003; 23:348.
  9. Rabindranath KS, Adams J, Ali TZ, et al. Continuous ambulatory peritoneal dialysis versus automated peritoneal dialysis for end-stage renal disease. Cochrane Database Syst Rev 2007; :CD006515.
  10. Rabindranath KS, Adams J, Ali TZ, et al. Automated vs continuous ambulatory peritoneal dialysis: a systematic review of randomized controlled trials. Nephrol Dial Transplant 2007; 22:2991.
  11. Michels WM, Verduijn M, Boeschoten EW, et al. Similar survival on automated peritoneal dialysis and continuous ambulatory peritoneal dialysis in a large prospective cohort. Clin J Am Soc Nephrol 2009; 4:943.
  12. Mehrotra R, Chiu YW, Kalantar-Zadeh K, Vonesh E. The outcomes of continuous ambulatory and automated peritoneal dialysis are similar. Kidney Int 2009; 76:97.
  13. Sun CY, Lee CC, Lin YY, Wu MS. In younger dialysis patients, automated peritoneal dialysis is associated with better long-term patient and technique survival than is continuous ambulatory peritoneal dialysis. Perit Dial Int 2011; 31:301.
  14. Bieber SD, Burkart J, Golper TA, et al. Comparative outcomes between continuous ambulatory and automated peritoneal dialysis: a narrative review. Am J Kidney Dis 2014; 63:1027.
  15. Michels WM, Verduijn M, Grootendorst DC, et al. Decline in residual renal function in automated compared with continuous ambulatory peritoneal dialysis. Clin J Am Soc Nephrol 2011; 6:537.
  16. Lan PG, Johnson DW, McDonald SP, et al. The association between peritoneal dialysis modality and peritonitis. Clin J Am Soc Nephrol 2014; 9:1091.
  17. Twardowski ZJ. PET--a simpler approach for determining prescriptions for adequate dialysis therapy. Adv Perit Dial 1990; 6:186.
  18. Twardowski ZJ. Nightly peritoneal dialysis. Why, who, how, and when? ASAIO Trans 1990; 36:8.
  19. Davies SJ, Phillips L, Griffiths AM, et al. What really happens to people on long-term peritoneal dialysis? Kidney Int 1998; 54:2207.
  20. Rodriguez-Carmona A, Pérez-Fontán M, Garca-Naveiro R, et al. Compared time profiles of ultrafiltration, sodium removal, and renal function in incident CAPD and automated peritoneal dialysis patients. Am J Kidney Dis 2004; 44:132.
  21. Bro S, Bjorner JB, Tofte-Jensen P, et al. A prospective, randomized multicenter study comparing APD and CAPD treatment. Perit Dial Int 1999; 19:526.
  22. Tang SC, Lam B, Ku PP, et al. Alleviation of sleep apnea in patients with chronic renal failure by nocturnal cycler-assisted peritoneal dialysis compared with conventional continuous ambulatory peritoneal dialysis. J Am Soc Nephrol 2006; 17:2607.
  23. Pérez-Fontán M, Rodríguez-Carmona A. Comparing CAPD and automated peritoneal dialysis: where do solute transport issues stand? Perit Dial Int 2007; 27:162.
  24. Demetriou D, Habicht A, Schillinger M, et al. Adequacy of automated peritoneal dialysis with and without manual daytime exchange: A randomized controlled trial. Kidney Int 2006; 70:1649.