A Reference Equation for Objectively Adjusting Dwell Volume to Obtain More Ultrafiltration in Daily Practice of Peritoneal Dialysis

Abstract

Objectives. Few studies mention how to objectively adjust peritoneal dialysis (PD) dwell volume for adult continuous ambulatory peritoneal dialysis (CAPD) patients. We proposed a reference equation composed of parameters from the peritoneal equilibrium test (PET) for adjusting daily dialysate dwell volume to obtain more ultrafiltration volume. Better fluid control could reduce more fluid overload-related complications. Design. We used body mass index, waist circumference, intraperitoneal pressure, and other parameters from peritoneal equilibrium test to compose a reference equation for fine-tuning daily dwell volume. Patients and Setting. Eighty-eight PD patients in one center with laboratory data collected during half-yearly PET evaluations were enrolled. Instilled dialysate was composed of 2.57% glucose PD fluid, either 1500 ml or 2000 ml in volume. In addition to other demographic data, intraperitoneal pressure (IPP) was also measured twice in the supine position four hours apart. We applied statistical multivariate techniques of discrimination analysis and logistic regression to verify the most feasible and optimal formula to determine infill volumes for patients. Results. We determined a novel formula for calculating daily dialysate dwell volume, Z: Z = (0.523 × waist circumference) + (0.852 × body mass index), derived from rotating axes to obtain an accurate prediction rate of 80.68% using the multivariate approach. Conclusion. The novel formula used objective, real-time parameters for determining appropriate dwell volumes for PD patients to optimize maximal ultrafiltration volumes and reduce subjective abdominal discomfort. The novel formula makes frequent adjustment of daily dwell volume by physicians or patients easy to calculate.