OBJECTIVE: To compare the accuracy and convenience of 3 methods for measuring drain volume for peritoneal dialysis (PD) clearance studies. DESIGN: Prospective comparison of both automated PD (APD) and continuous ambulatory PD (CAPD) clearance study methods. SETTING: Adults > or = 18 years old at 2 dialysis clinics. PATIENTS: 28 PD patients with 43 clearance studies, 15 on CAPD and 28 on APD. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Drain volume was determined by 3 methods for each study: (1) graduate-measured volume using a 2-L graduated cylinder; (2) weighed volume, with and without bag weight, using a digital floor scale or spring scale; (3) cycler-measured volume using the initial drain and ultrafiltration indicated by the cycler, plus the prescribed inflow volume without the last fill. RESULTS: There was no statistically significant difference in volumes using the 3 methods studied (all p > 0.89 for APD, all p > 0.97 for CAPD). Effluent volume was more accurate with the weight of the bag subtracted. CONCLUSION: The most convenient and a precise method for APD is to determine the effluent drain volume using the prescription and total ultrafiltration and initial drain, as measured by the cycler. For CAPD, using the weight of drained bags is accurate but the weight of the empty bag must be subtracted. These approaches have the least risk of exposing staff to body fluids.
OBJECTIVE: To compare the accuracy and convenience of 3 methods for measuring drain volume for peritoneal dialysis (PD) clearance studies. DESIGN: Prospective comparison of both automated PD (APD) and continuous ambulatory PD (CAPD) clearance study methods. SETTING: Adults > or = 18 years old at 2 dialysis clinics. PATIENTS: 28 PDpatients with 43 clearance studies, 15 on CAPD and 28 on APD. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Drain volume was determined by 3 methods for each study: (1) graduate-measured volume using a 2-L graduated cylinder; (2) weighed volume, with and without bag weight, using a digital floor scale or spring scale; (3) cycler-measured volume using the initial drain and ultrafiltration indicated by the cycler, plus the prescribed inflow volume without the last fill. RESULTS: There was no statistically significant difference in volumes using the 3 methods studied (all p > 0.89 for APD, all p > 0.97 for CAPD). Effluent volume was more accurate with the weight of the bag subtracted. CONCLUSION: The most convenient and a precise method for APD is to determine the effluent drain volume using the prescription and total ultrafiltration and initial drain, as measured by the cycler. For CAPD, using the weight of drained bags is accurate but the weight of the empty bag must be subtracted. These approaches have the least risk of exposing staff to body fluids.