What is the role of automated peritoneal dialysis and continuous flow peritoneal dialysis?

Access and Continuous Flow Peritoneal Dialysis

Continuous flow peritoneal dialysis (CFPD) presents many potential advantages over any conventional peritoneal dialysis modality. Foremost are the impressive clearances achieved by CFPD in clinical studies, approaching those of quotidian hemodialysis. The principal limitation of CFPD is its inability to provide adequate and consistent ultrafiltration in clinical practice, contrary to the high ultrafiltration predicted by theoretical models. There is a good possibility that this discrepancy is due to poor mixing, streaming, and recirculation of dialysate related to inadequate peritoneal access. Novel access designs are encouraging but await longitudinal clinical testing to prove their superiority.

Chronic Peritoneal Dialysis Catheters: Challenges and Design Solutions

Although highly successful as transcutaneous access devices, today's peritoneal dialysis catheters still have imperfect hydraulic function, biocompatibility and resistance to infection. Success of Tenckhoff catheters is greatly improved by the proper positioning of deep and subcutaneous cuffs and intraperitoneal segment. Newer peritoneal catheter designs are intended to improve hydraulic function, avoid outflow failure, and diminish exit site infection. These catheter designs serve as excellent alternatives for patients with various types of failure of Tenckhoff catheters. Catheters have been designed for Continuous Flow Peritoneal Dialysis, and have generally been successful in providing high peritoneal dialysis flow rate, but not always successful in optimally distributing flow of peritoneal fluid. Improvements in catheter design may expand the use of peritoneal dialysis as a successful home dialysis therapy.

Peritoneal cells at admission: do they have prognostic significance in peritonitis?

Peritonitis accounts for considerable morbidity and hospitalization in peritoneal dialysis (PD) patients. We investigated the factors related with time of hospital stay, especially focusing on the peritoneal cell profiles at the time of hospital admission in PD-related peritonitis. Eighty peritonitis attacks were evaluated. Data were collected at the time of hospital admission, clinical and biochemical parameters, including initial systemic and dialysate white cell counts (including percentage and differential count of neutrophils and lymphocytes) and length of hospital stay. Peritoneal leukocyte (r=+0.289, p=0.009) and neutrophil counts (r=+0.403, p<0.0001), peritoneal neutrophil percentage (r=+0.492, p<0.0001), time of hospital admission (r=+0.498, p<0.0001), and C-reactive protein (CRP) (r=+0.231, p=0.042) were positively correlated; lymphomononuclear cell percentage (r=-0.650, p<0.0001) was negatively correlated with hospitalization length. Hospital admission>or=24 hours of symptom onset was associated with higher CRP, dialysate leukocyte and neutrophil counts, longer hospitalization, and with lower dialysate lymphomononuclear cell percentage compared to admission<24 hours (p=0.04, p=0.04, p=0.005, p<0.0001, and p=0.04, respectively). In multiple linear regression, the time of hospital admission (p=0.002), initial peritoneal neutrophil count (p=0.011), and lymphomononuclear cell percentage (p<0.0001) were independently associated with hospitalization length. Hospital admission within first 24 hours of peritonitis symptoms onset is of vital importance; delayed admission is associated with higher peritoneal leukocyte and neutrophil counts, and increased length of hospital stay.

Continuous ambulatory peritoneal dialysis versus automated peritoneal dialysis for end-stage renal disease

BACKGROUND

Peritoneal dialysis (PD) can be performed either manually as in continuous ambulatory peritoneal dialysis (CAPD) or using mechanical devices as in automated PD (APD). APD has been considered to have several advantages over CAPD such as reduced incidence of peritonitis, mechanical complications and greater psychosocial acceptability.

OBJECTIVES

To assess the comparative efficacy of CAPD and APD in patients who are dialysed for end-stage renal disease (ESRD).

SEARCH STRATEGY

We searched MEDLINE, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), Cochrane Renal Group's specialised register and CINAHL. Authors of included studies were contacted, reference lists of identified RCTs and relevant narrative reviews were screened. Date of most recent search: May 2006

SELECTION CRITERIA

RCTs comparing CAPD with APD in patients with ESRD.

DATA COLLECTION AND ANALYSIS

Data were abstracted independently by two authors onto a standard form. Relative risk (RR) for dichotomous data and a mean difference (MD) for continuous data were calculated with 95% confidence intervals (CI).

MAIN RESULTS

Three trials (139 patients) were included. APD did not differ from CAPD with respect to mortality (RR 1.49, 95% CI 0.51 to 4.37), risk of peritonitis (RR 0.75, 95% CI 0.50 to 1.11), switching from original PD modality to a different dialysis modality (RR 0.50, 95% CI 0.25 to 1.02), hernias (RR 1.26, 95% interval 0.32 to 5.01), PD fluid leaks (RR 1.06, 95% CI 0.11 to 9.83), PD catheter removal (RR 0.64, 95% CI 0.27 to 1.48) or hospital admissions (RR 0.96, 95% CI 0.43 to 2.17). There was no difference between either PD modality with respect to residual renal function (MD -0.17, 95% CI -1.66 to 1.32). One study found that peritonitis rates and hospitalisation were significantly less in patients on APD when results were expressed as episodes/patient-year. Another study found that patients on APD had significantly more time for work, family and social activities.

AUTHORS' CONCLUSIONS

APD has not been shown to have significant advantages over CAPD in terms of important clinical outcomes. APD may however be considered advantageous in select group of patients such as in the younger PD population and those in employment or education due to its psychosocial advantages. There is a need for a RCT comparing CAPD with APD with sufficiently large patient numbers looking at important clinical outcomes including residual renal function, accompanied by an economic evaluation to clarify the relative clinical and cost-effectiveness of both modalities.