Solutions for APD: special considerations

Single-dwell treatment with a low-sodium solution in hypertensive peritoneal dialysis patients

BACKGROUND

Patients on peritoneal dialysis (PD) may suffer from sodium (Na) and fluid overload, hypertension and increased cardiovascular risk. Low-Na dialysis solution, by increasing the diffusive removal of Na, might improve blood pressure (BP) management.

METHODS

A glucose-compensated, low-Na PD solution (112 mmol/L Na and 2% glucose) was compared to a standard-Na solution (133 mmol/L Na and 1.5% glucose) in a prospective, randomised, single-blind study in hypertensive patients on PD. One daily exchange of the standard dialysis regimen was substituted by either of the study solutions for 6 months. The primary outcome (response) was defined as either a decrease of 24-h systolic BP (SBP) by ≥6 mmHg or a fall in BP requiring a medical intervention (e.g. a reduction of antihypertensive medication) at 8 weeks.

RESULTS

One hundred twenty-three patients were assessed for efficacy. Response criteria were achieved in 34.5% and 29.1% of patients using low- and standard-Na solutions, respectively (p = 0.51). Small reductions in 24 h, office, and self-measured BP were observed, more marked with low-Na than with standard-Na solution, but only the between-group difference for self-measured SBP and diastolic BP was significant (p = 0.002 and p = 0.003). Total body water decreased in the low-Na group and increased in the control group, but between-group differences were not significant. Hypotension and dizziness occurred in 27.0% and in 11.1% of patients in the low-Na group and in 16.9% and 4.6% in the control group, respectively.

CONCLUSIONS

Superiority of low-Na PD solution over standard-Na solution for control of BP could not be shown. The once daily use of a low-Na PD solution was associated with more hypotensive episodes, suggesting the need to reassess the overall concept of how Na-reduced solutions might be incorporated within the treatment schedule.

Volume Control in Peritoneal Dialysis Patients: Role of New Dialysis Solutions

This paper reviews the most recent clinical data on the volume status of long-term peritoneal dialysis (PD) patients. It appears that many PD patients are volume overloaded, associated with a high prevalence of hypertension and left ventricular hypertrophy. In the presence of the poor results in patients with peritoneal ultrafiltration, the introduction of the polyglucose solution, icodextrin, has ameliorated volume control in some of these patients. In a second part of the review, some of the structural and functional alterations in the peritoneal membrane and the role of glucose degradation products (GDP) in the commonly used dialysates as well as the resulting formation of advanced glycation end products are described. The introduction of low GDP-containing solutions at normal pH has at least in experimental models of PD attenuated the hemodynamic changes observed with the classical solutions. The solutions at normal pH containing either bicarbonate or a mixture of bicarbonate/lactate were clinically associated with less inflow pain.

The future of APD

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.