The fluid study protocol: a randomized controlled study on the effects of bioimpedance analysis and vitamin D on left ventricular mass in peritoneal dialysis patients.

OBJECTIVES: We will evaluate the effects of bioimpedance analysis-guided fluid management to reduce volume expansion, of vitamin D(3) supplementation, and of the combination of those techniques on decrease of left ventricular mass in peritoneal dialysis (PD) patients. DESIGN: This multicenter randomized controlled trial, with a 2 × 2 factorial design, will be conducted at PD clinics affiliated with 3 Canadian teaching hospitals. Consenting PD patients 18 years of age or older will be included. Patients will be excluded if they have contraindications to bioimpedance or magnetic resonance imaging, life or technique expectancy of less than 1 year, peritonitis within the preceding 3 months, or serum calcium above 2.55 mmol/L. INTERVENTION: The study will randomize 70 patients to bio-impedance-guided volume management or to usual care and to vitamin D(3) 50,000 U weekly for 8 doses, and then 10,000 U weekly or to matching placebo. MAIN OUTCOME MEASURES: The primary outcome will be change in left ventricular mass at 1 year as determined by cardiac magnetic resonance imaging. The secondary outcome will be a composite endpoint of death, nonfatal cardiovascular event, and transfer to hemodialysis for dialysis inadequacy or ultrafiltration failure. Other outcome measures will include blood pressure, quality of life, 6-minute walk test, inflammatory and fibrotic markers and their association with peritoneal membrane transport properties, and residual renal function. Patients will be followed for clinical outcomes for up to 3 years. CONCLUSIONS: This study will assess whether bioimpedance-directed volume management and vitamin D(3) supplementation can improve left ventricular mass in PD patients.

Management of hypophosphatemia in nocturnal hemodialysis with phosphate-containing enema: a technical study.

Hypophosphatemia is observed in patients undergoing nocturnal hemodialysis. Phosphate is commonly added to the dialysate acid bath, but systematic evaluation of the safety and reliability of this strategy is lacking. The objectives of this study were 4-fold. First, we determined whether predictable final dialysate phosphate concentrations could be achieved by adding varying amounts of Fleet® enema. Second, we assessed the stability of calcium (Ca) and phosphate dialysate levels under simulated nocturnal hemodialysis conditions. Third, we assessed for Ca-phosphate precipitate. Finally, we evaluated whether dialysate containing Fleet® enema met the current sterility standards. We added serial aliquots of enema to 4.5 L of dialysate acid concentrate and proportioned the solution on Gambro and Althin/Baxter dialysis machines for up to 8 hours. We measured dialysate phosphate, Ca, pH, and bicarbonate concentrations at baseline, and after simulated dialysis at 4 and 8 hours. We evaluated for precipitation visually and by assessing optical density at 620 nm. We used inoculation of agar to detect bacteria and Pyrotell reaction for endotoxin. For every 30 mL of Fleet® (1.38 mmol/mL of phosphate) enema added, the dialysate phosphate concentration increased by 0.2 mmol/L. There were no significant changes in dialysate phosphate, Ca, pH, and bicarbonate concentrations over 8 hours. No precipitate was observed in the dialysate by optical density measures at 620 nm for additions of up to 90 mL of enema. Bacterial and endotoxin testing met sterility standards. The addition of Fleet® enema to dialysate increases phosphate concentration in a predictable manner, and no safety problems were observed in our in vitro studies.