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Preservation of residual renal function and reduced early mortality rates are likely to reflect the relative ease with which euvolemia can be achieved in peritoneal dialysis (PD) patients. Yet, there is concern that these patients are frequently fluid loaded, fuelled by the problems of ultrafiltration failure and worse survival observed in anuric patients with low fluid removal. In reality, the proportion of PD patients that are overhydrated is not dissimilar to hemodialysis but the challenges in achieving euvolemia might be different. These include (i) the undesirability of driving down the dry weight, in part to avoid excess glucose exposure, in part because there is a trade off in preserving residual renal function, (ii) limitations in our knowledge of how best to measure and apply measurements of fluid status in clinical practice, (iii) limitations imposed by the therapy itself (e.g., membrane function, sodium sieving), and (iv) the influence of hypoalbuminemia on fluid distribution. Treatment options that enable improved fluid management are available (e.g., automated peritoneal dialysis and icodextrin for rapid transporters, dietary salt restriction) or on the horizon (e.g., low sodium dialysates). We now need studies that aid clinicians in their decision making to enable best fluid management in their patients.

We review the role of automated peritoneal dialysis (APD) in improving outcomes of an end-stage renal disease (ESRD) program. As the "integrated care approach" becomes accepted as the preferred strategy for treatment of ESRD patients, we looked for the potential place of APD in such an approach. APD has probably the same advantages as CAPD as a first-line renal replacement modality in suitable patients willing to perform PD. There is currently no hard evidence that residual renal function (RRF) should decline more rapidly in APD than in CAPD, at least if a dry abdomen during the day is avoided. The detection of peritonitis is probably more delayed in APD, but the frequency of peritonitis is lower, and there is no hard evidence pointing to a poorer outcome of peritonitis in APD as compared to CAPD. Quality of life is at least as good in APD, which is mostly related to the increased possibilities for adapting the exchange pattern to employment-related time frames. APD also has the potential to prolong technique success in patients failing CAPD rather than transferring them to hemodialysis. Nevertheless, APD remains more expensive and technically complicated, thereby missing the beauty of CAPD's simplicity. Therefore we believe that APD has its role in an integrated approach and that all patients should be informed of its potential. It would, however, not be correct to present APD as the preferred PD method for all patients, as it also has some drawbacks that make it less suitable for some categories of patients. In all cases, patients should have a free and informed choice.

Few elderly patients with end-stage renal disease (ESRD) are treated with peritoneal dialysis (PD). Among dialysis patients >or=65 years of age reported by the U.S. Renal Data System (USRDS), the percentage treated with chronic peritoneal dialysis (CPD) is lower than in any other age group. To evaluate the effectiveness of automated peritoneal dialysis (APD) in the elderly, we compared several outcome measures in cohorts of different ages maintained on APD. The outcome measures we examined included mortality and technique failure rates, peritonitis rates, outcomes of peritonitis, and quality of life measures. We found that while patients >or=65 years of age have a higher mortality rate than younger patients, technique failure rates, overall peritonitis rates, and most quality of life measures are not different than for younger patients. However, patients >or=65 years of age have higher gram-negative peritonitis rates and lower scores on the physical component score of the SF-36 than younger patients. The present study suggests that APD is a reasonable treatment modality for elderly patients with ESRD and that elderly patients with progressive renal failure should be considered as candidates for APD.

The incidence of peritonitis in peritoneal dialysis (PD) has further decreased after the introduction of automated peritoneal dialysis (APD) into clinical routine. Technical advances such as a reduction in the number of connections, more motivated patients, and improved host defense mechanisms in APD have been described. We found that the long daytime interval without dialysate exchanges leads to a higher absolute number of peritoneal macrophages which are capable of an improved first-line host defense. This is demonstrated by a higher release of cytokines of peritoneal macrophages after stimulation with lipopolysaccharides. The dry "day" in nightly intermittent PD seems to have no relevant additional positive effects on peritoneal host defense compared to continuous cyclic peritoneal dialysis. The regeneration of peritoneal cell populations induced by intervals without PD remains relevant even in times when more "biocompatible" PD solutions become available.

Automated peritoneal dialysis (APD) is increasingly popular compared to continuous ambulatory peritoneal dialysis (CAPD). It not only can provide more solute clearance and ultrafiltration than its CAPD counterpart, but it is conducive to a more convenient lifestyle as well. Using relatively smaller-volume daytime dwells, with the use of larger-volume exchanges while the patient is recumbent during the night, is an attractive approach. Advantages of supine exchanges include greater small molecule clearances for equivalent flow rates and decreased intra-abdominal pressure per volume of dialysate (as intraperitoneal pressure parallels intraperitoneal volume). Urea nitrogen clearance can be optimally increased on APD by increasing both the exchange volume and the frequency of exchanges at night. This is even true for anuric low transporters. This approach allows daytime exchanges and volumes to be minimized. Historic studies in peritoneal dialysis including flow rate analysis, clearance and adequacy studies, as well as tolerance have primarily involved CAPD. As a result, there is a paucity of investigations involving APD. More research is required in APD related to these subjects.

A generalized kinetic model to quantify the efficiency of cycler (CPD) and tidal peritoneal dialysis (TPD) is used to examine the relative efficiency of these techniques over a wide range of tidal volumes, drain profile characteristics, and hourly dialysate flow rates. In the patient with good catheter function, there is little difference in efficiency between CPD and TPD. In patients with long drain times or nonlinear drain profiles, greatly improved efficiency may theoretically be achieved with small tidal volume TPD. A generalized solution of the continuous flow PD (CFPD) kinetic model is used to demonstrate and contrast the kinetics of automated PD (APD) and CFPD.

In the early 1960s, peritoneal dialysis (PD) was introduced as a form of long-term maintenance therapy in patients with end-stage renal disease (ESRD). We have come a long way since. Increasing understanding of peritoneal kinetic behavior, its innovative manipulation to meet patient needs, critical monitoring of clinical outcomes, and parallel development in technology have all contributed to the worldwide success of the therapy over the past four decades. In this article we review the evolution of the various PD modalities in the context of these factors.

Automated peritoneal dialysis (APD) has experienced significant growth in highly developed nations in the last few years, while in developing countries with important social, educational, and financial constraints this treatment modality is, at best, trying to emerge. APD offers advantages that make it popular. Some of these advantages include increased adequacy for some patient groups, enhanced patient well-being and positive changes in lifestyle, as well as a reduction in peritonitis rates attributed to fewer connect-disconnect procedures. The development of APD in developing nations has been very poor mainly due to educational and financial constraints. APD growth as a treatment modality in the developing world requires multiple approaches, some of them general and others related to the specific needs of each nation. There is a need to develop APD research projects and pilot programs to demonstrate the benefits for specific subpopulations. In addition, the development of research and industry-market strategies directed at reducing costs related to this form of treatment are required. The relatively low use of APD in developing nations is primarily influenced by nonmedical factors. Given the financial and educational constraints, APD programs may need to be directed toward specific subpopulations such as young working adults, individuals who require assistance to perform procedures, or patients who require an increased dialysis dose in order to reach adequate clearances.

The future of automated peritoneal dialysis (APD) greatly depends on its ability to provide optimal clearances and volume control, preserve peritoneal transport, maintain adequate peritoneal access, and offer flexibility of prescription at a reasonable and competitive cost. Each of these aspects are discussed in the light of recent technologic advances and clinical experiences in order to project a vision of the potential future of APD.

Lack of compliance with prescribed treatment is an important cause of inadequate dialysis in patients on peritoneal dialysis (PD). The reported prevalence of noncompliance with treatment in PD varies from 5 to 38%. The predictors of noncompliance, its consequences, methods to identify and monitor compliance, differences in frequency between continuous ambulatory PD (CAPD) and automated PD (APD), and management are reviewed. The risk of noncompliance is greater in CAPD than in APD. Noncompliance should be managed by patient education and appropriate modification of therapy, including consideration of APD.

Automated peritoneal dialysis (APD) is the fastest growing technique of peritoneal dialysis. However, recently APD has displayed some limitations imposed by the characteristics of the technique and by the characteristics of the peritoneal membrane of some patients. In general, the advent of a new technique such as continuous flow peritoneal dialysis (CFPD) should be seen as a benefit for several patients based on different considerations: CFPD is a high-efficiency technique which could overcome some of the limitations imposed by other techniques in terms of adequacy targets and performance. CFPD may become a useful tool to keep patients on PD who would otherwise be transferred to hemodialysis. CFPD may present advantages in terms of biocompatibility and also in terms of the possible modulation of the peritoneal solution to patient needs. Recent developments in technology seem to have made CFPD easily feasible and well tolerated. A new era of PD is probably beginning and CFPD will definitely represent one of the key issues in the future of PD.