Method for determining the intraperitoneal volume and device for peritoneal dialysis
A method and device are provided for determining a intraperitoneal volume during peritoneal dialysis. The method and device can be used in conjunction with a dialysis machine wherein a first circuit peritoneal solution from a patient's peritoneal cavity is carried past one side of a semipermeable membrane and dialyzing fluid in a second circuit is carried past the other side of the membrane. The concentration of an endogenous substance (which during peritoneal dialysis passes through the peritoneum into the peritoneal cavity) is measured during the treatment. The intraperitoneal volume is calculated from the measured variation in concentration of the endogenous substance in the peritoneal solution. Preferably, the endogenous substance is albumin. The concentration of the endogenous substance preferably is measured at two successive times. After the first measurement, a predetermined volume of fluid ΔV is withdrawn from or added to the first circuit.
1. A method for determining an intraperitoneal volume during peritoneal dialysis, comprising the steps of:
passing a peritoneal solution from a peritoneal cavity in a first circuit adjacent a first side of a semipermeable membrane; passing a dialyzing fluid in a second circuit adjacent a second side of the semipermeable membrane;
measuring the concentration of an endogenous substance in the peritoneal solution, wherein the endogenous substance passes through a peritoneum into the peritoneal solution in the peritoneal cavity; and
determining the intraperitoneal volume from the variation in the concentration over time.
2. The method according to claim 1 , wherein the measuring step further comprises:
measuring the concentration c 0 of the endogenous substance in the peritoneal solution at a time t 1 ;
withdrawing or delivering a predetermined volume ΔV of fluid in the first circuit;
measuring the concentration c 1 of the endogenous substance in the peritoneal solution at a time t 2 ; and
wherein the determining step further comprises:
determining the intraperitoneal volume from the equation:
V
=
Δ
V
1
-
c
0
/
c
1
.
3. The method according to claim 2 , which further comprises the step of:
determining an ultrafiltration rate V (t 1 )/t 1 from the variation in intraperitoneal volume in the time t 1 -t 2 ;
withdrawing fluid from the first circuit at the ultrafiltration rate.
4. The method according to claim 3 , which further comprises the step of:
determining continuously the variation in intraperitoneal volume during peritoneal dialysis for determination of the ultrafiltration rate.
5. The method according to claim 1 , wherein the endogenous substance is albumin.