Apparatus and method for automatically performing peritoneal equilibration tests

A method of automatically conducting peritoneal equilibration tests, comprising:

• removing a sample of overnight dwell fluid through a line from a patient in an amount sufficient to determine the concentration of a metabolite therein, said line being connected to control means for controlling removal of said sample;
• detecting the concentration of at least one metabolite in said sample of overnight dwell fluid with detecting means for detecting said concentration, said detecting means being connected to said line and associated with said control means;
• draining all overnight dwell fluid from a patient through said line under control of said control means to result in a drained overnight dwell fluid, and determining the weight of said drained overnight dwell fluid with weight means for weighing, associated with said control means;
• instilling a known weight of dialysate fluid into a patient through said line under control of said control means;
• periodically drawing samples of said dialysate fluid, under control of said control means, to result in periodically drawn samples of dialysate fluid, and determining the concentration of the metabolite in each one of said periodically drawn samples of dialysate fluid, with said detecting means;
• determining the ratio of said metabolite concentration detected for each one of said periodically drawn samples of dialysate fluid to the metabolite concentration detected of said sample of overnight dwell fluid or other estimate of plasma water concentration, said determination being done by said control means;
• draining the patient of said instilled dialysate fluid after a predetermined dwell time under control of said control means, and determining the volume of said drained dialysate fluid;
• and
• determining the mass transfer area coefficient of the patient's peritoneal membrane as a function of said known volume of dialysate fluid infused, known volume of drained dialysate fluid and the determined ratios of said metabolite concentration for each of said periodically drawn samples of dialysate fluid, to the metabolite concentration of said sample of overnight dwell fluid or other estimate of plasma water concentration.