Minimizing the drainage period for continuous ambulatory peritoneal dialysis.

OBJECTIVES: To examine features of drainage flow and to determine whether the drainage period could be safely reduced in continuous ambulatory peritoneal dialysis (CAPD) patients. DESIGN: Open nonrandomized prospective study in CAPD patients. SETTING: The kidney center in a tertiary care university hospital. PATIENTS: Fourteen CAPD patients with good catheter function. INTERVENTIONS: Drainage flow pattern was studied using a 2-L dialysate. The drainage period was reduced from 28 minutes (mean) to 10 minutes throughout a short-term, 2-month study period and a long-term, 6-month study period for 10 patients. MAIN OUTCOME MEASURES: Ultrafiltration volume, body weight, and peritoneal clearance. RESULTS: A kinetics analysis of the drainage period and volume indicated a positive linear correlation with two different slopes: one for rapid drainage for the first 5-7 minutes and one for subsequent slow drainage. The effluent exceeded 80% in the former period. Ultrafiltration volume and body weight showed no change due to the reduction. Improved peritoneal clearance of small molecular substances could not be confirmed despite a 5% increase in the effective dialysis period. Nearly all patients were satisfied with the reduction and desired its continuation. CONCLUSIONS: Ten minutes is a sufficient drainage period for most CAPD patients with a 2-L dialysate volume. This may possibly allow an increase in daily activities and an effective peritoneal membrane dialysate contact period.