Artificial kidney and method for adjusting a concentration of substance in blood using thereof

• US 5,578,223 A
• Filed: 02/03/1995
• Issued: 11/26/1996
• Est. Priority Date: 09/10/1991
• Status: Expired due to Term

• Current Assignee: Industries Gambro
• Original Assignee: Hospal Industrie
• Inventors: Chevallet, Jacques, Bene, Bernard
• Primary Examiner(s): KIM, SUN U
• Application Number:
  US08/383,208
• Time in Patent Office: 662 Days
• Field of Search: 210/645, 210/646, 210/650, 210/739, 210/929, 210/85, 210/87, 210/97, 210/103, 210/134, 210/143, 210/195.2, 210/257.2, 210/117, 210/258, 210/321.6, 210/321.65 , 210/321.71, 210/321.72, 210/321.75, 210/321.84, 604/4, 604/5, 604/6
• US Class Current: 210/85
• CPC Class Codes: A61M 1/16 with membranes
• CPC Class Codes: A61M 1/1605 Physical characteristics of the dialysate fluid
• CPC Class Codes: A61M 1/1643 with weighing of fresh and used dialysis fluid
• CPC Class Codes: A61M 1/341 by measuring the filtrate rate or volume
• CPC Class Codes: A61M 1/3413 Diafiltration
• CPC Class Codes: A61M 1/3437 downstream of the filter, e.g. post-dilution with filtrate
• CPC Class Codes: A61M 1/3441 Substitution rate control as a function of the ultrafiltration rate
• CPC Class Codes: A61M 1/3451 the difference in weight between both ultra-filtrate and substitution reservoir being used as control signal
• CPC Class Codes: A61M 1/3458 having electrolytes not present in the dialysate
• CPC Class Codes: A61M 1/3465 using dialysate as substitution fluid
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: Y10S 210/929 Hemoultrafiltrate volume measurement or control processes

Abstract

An artificial kidney comprises an exchanger (1) having two compartments (2, 3) separated by a semipermeable membrane (4), a first compartment (2) being connected to a circuit (5, 7) for extracorporeal blood circulation, the second compartment (3) having an outlet for draining waste liquid. Means (22, 25) are provided for controlling the flow rate (Q_A) of a sterile solution containing a substance (A) to be perfused into the circuit (5, 7) for conveying a flow of blood outside the body, which flow rate is controlled as a function of the flow rate (Q_OUT) of waste liquid. This kidney makes it possible to dose a substance such as a medicine, glucose or bicarbonate, accurately into the blood of a patient undergoing treatment by hemofiltration, hemodialysis, or hemodiafiltration.

Claims

1. An artificial kidney, comprising:

an exchanger having first and second compartments separated by a semipermeable membrane, the first compartment being connected to a blood circuit for conveying a flow of blood outside a body of a patient, and the second compartment having an outlet for draining a waste liquid;

a source of perfusion liquid for containing a substance (A) having a concentration [A]_SOL ;

means for connecting the source of perfusion liquid to the patient;

means for varying a flow rate of the perfusion liquid to the patient; and

dosage means for adjusting a concentration of the substance (A) in the blood of the patient to a desired concentration [A]_DES, the dosage means including means for determining a flow rate (Q_OUT) of the waste liquid from the second compartment of the exchanger, means for calculating a flow rate (Q_A) of the perfusion liquid as a function of the flow rate (Q_OUT) of the waste liquid, means for controlling the flow varying means so that an actual flow rate of the perfusion liquid is substantially equal to the calculated flow rate (Q_A).

2. An artificial kidney according to claim 1, wherein the calculating means calculates the flow rate (Q_A) of the perfusion liquid from the flow rate (Q_OUT) of the waste liquid using the equation:

##EQU5##

3. An artificial kidney according to claim 1, wherein the calculating means determines the flow rate (Q_A) of the perfusion liquid using the equation:

##EQU6## where Cl is the clearance of the artificial kidney for the substance (A).

4. An artificial kidney according to claim 1, wherein the means for connecting the source of perfusion liquid to the patient includes a duct connected to the blood circuit.

5. An artificial kidney according to claim 4, wherein the means for varying the flow rate of the perfusion liquid includes a pump located on the duct.

6. An artificial kidney according to claim 1, wherein the substance (A) is bicarbonate.

7. An artificial kidney according to claim 6, further including a source of bicarbonate-free substitution liquid connected to the blood circuit.

8. An artificial kidney according to claim 6, further including a source of bicarbonate-free dialysis liquid connected to an inlet of the second compartment of the exchanger.

9. An artificial kidney according to claim 6, further including a source of bicarbonate-free substitution/dialysis liquid connected to the blood circuit and to an inlet of the second compartment of the exchanger, and blocking means for selectively isolating the source, and enabling the substitution/dialysis liquid to flow out into the blood circuit body, and alternatively allowing the substitution/dialysis liquid to flow into the second compartment of the exchanger.

10. An artificial kidney according to claim 1, further including means for varying an ultrafiltration flow rate through the exchanger.

11. An artificial kidney according to claim 10, wherein the means for controlling the ultrafiltration flow rate varying means controls the ultrafiltration flow rate as a function of a difference between liquids flow and a given reference value for a weight loss flow rate (Q_WL).

12. An artificial kidney according to claim 1, further including means for measuring a difference between an amount of liquid injected into the blood circuit and an amount of waste liquid flowing out of the second compartment of the exchanger, the waste liquid being from a group consisting of ultrafiltrate and waste dialysis liquid.

13. An artificial kidney according to claim 12, wherein the means for measuring the difference between the amounts of liquids includes scales for weighing a container constituting a source of substitution/dialysis liquid, and a container for collecting waste liquid, and scales for weighing a container constituting a source of solution containing the substance (A).

14. A method for adjusting a concentration of a substance (A) to a desired concentration [A]_DES in blood of a patient undergoing an extracorporeal blood treatment using an exchanger having an outlet for a waste liquid, the method comprising the steps of:

circulating the blood of the patient through the exchanger;

draining waste liquid from the exchanger;

perfusing to the patient a liquid containing a substance (A) having a concentration [A]_SOL ;

determining a flow rate (Q_OUT) of the waste liquid drained from the exchanger;

calculating a flow rate (Q_A) of the perfusion liquid as a function of the flow rate (Q_OUT) of the waste liquid; and

regulating the concentration of substance (A) in the patent'"'"'s blood by controlling a flow rate of the perfusion liquid so that an actual flow rate of the perfusion liquid is substantially equal to the calculated flow rate (Q_A).

15. A method according to claim 14, wherein the flow rate (Q_A) of the perfusion liquid is calculated from the flow rate (Q_OUT) of the waste liquid according to the equation:

##EQU7##

16. A method according to claim 14, wherein the flow rate (Q_A) of the perfusion liquid is calculated according to the equation:

##EQU8## where Cl is the clearance of the artificial kidney for the substance (A).

17. A method according to claim 14, wherein the step of determining a flow rate (Q_OUT) of the waste liquid from the exchanger comprises the substeps of:

continuously collecting the waste liquid in a container;

continuously weighing the container; and

calculating the flow rate (Q_OUT) of the waste liquid based on an increase in weight of the container.

18. A method according to claim 14, wherein the step of controlling a flow rate of the perfusion liquid comprises the substeps of:

continuously weighing a container containing the perfusion liquid;

calculating an actual flow rate of the perfusion liquid from a decrease in weight of the container;

comparing the actual flow rate to the calculated flow rate (Q_A) of the perfusion liquid; and

regulating the flow rate of the perfusion liquid so that it is substantially equal to the calculated flow rate (Q_A).

19. A method according to claim 14, wherein the substance (A) is bicarbonate.