Method and device for monitoring the access to the cardiovascular system of a patient

• US 6,932,786 B2
• Filed: 12/22/2000
• Issued: 08/23/2005
• Est. Priority Date: 12/28/1999
• Status: Expired due to Term

• Current Assignee: Baxter Healthcare SA (Baxter International Inc.)
• Original Assignee: Gambro Hospal Schweiz AG
• Inventors: Rossi, Ivan, Giacomelli, Sara, Canini, Enrico
• Primary Examiner(s): Sykes, Angela D.
• Assistant Examiner(s): Deak, Leslie R.
• Application Number:
  US09/914,348
• Publication Number:
  US 20030036719A1
• Time in Patent Office: 1,705 Days
• Field of Search: 604/5.04, 604/4.01, 604/6.06, 604/6.08, 604 609- 611, 604/6.16, 604/67, 604/65, 604/5.01, 210645-646, 210/103, 210/85, 210/87, 738/610.8, 422/44
• US Class Current: 604/6.08
• CPC Class Codes: A61M 1/16 with membranes
• CPC Class Codes: A61M 1/3656 Monitoring patency or flow at connection sites; Detecting disconnections
• CPC Class Codes: A61M 1/3669 Electrical impedance measurement of body fluids; transducers specially adapted therefor
• CPC Class Codes: A61M 1/367 Circuit parts not covered by the preceding subgroups of group A61M1/3621
• CPC Class Codes: A61M 2205/13 with means for the detection of operative contact with patient, e.g. lip sensor
• CPC Class Codes: A61M 2205/50 with microprocessors or computers

Abstract

A device for monitoring the access to the cardiovascular system of a patient undergoing an extracorporeal treatment of blood in a machine (1) comprising a treatment device (4) and an extracorporeal circuit (2), comprises: a voltage generator (16) for generating a potential difference between a part of the machine (1) and a first point (B) of a venous branch (8) of the extracorporeal circuit (2), connecting the patient to the treatment device (4); a detector (17) for detecting the value (dV) of a quantity that correlates with the electric current along at least one section (10a; 10b; 10c) of the venous branch (10) between the first point (B) and a venous needle (13) fitted at the end of the venous branch (8) and inserted in the vascular system of the patient (P); calculating means (15) for comparing the detected value (dV) with a reference range (I).

Claims

1. A method of monitoring a cardiovascular access during an extracorporeal blood treatment, comprising the steps of:

providing an extracorporeal blood circuit comprising an arterial branch and a venous branch, the arterial branch connecting an arterial needle inserted into a patient to an inlet of a blood treatment device, the venous branch connecting an outlet of the blood treatment device to a venous needle inserted into a patient;

providing a conductive connection between the arterial branch and the venous branch, said conductive connection having first and second connection locations, wherein said first connection location is located upstream of the blood treatment device and said second connection location is located downstream of said blood treatment device;

circulating blood in the extracorporeal blood circuit;

generating a potential difference between the arterial branch and the venous branch;

detecting a value of a quantity corresponding to an electric current along at least one portion of the venous branch, said at least one portion being between the conductive connection and the venous needle; and

comparing the detected value to a reference range.

2. A method according to claim 1, wherein an end of the conductive connection is located on the venous branch between the venous needle and a bubble trap, said bubble trap being connected to the venous branch.

3. A method according to claim 1, wherein an end of the conductive connection is located on the arterial branch between the arterial needle and a peristaltic pump arranged on the arterial branch.

4. A method according to claim 1, wherein said quantity corresponding to an electric current is a voltage drop.

5. A method according to claim 1, wherein a capacitive coupler connects the conductive connection to the arterial branch.

6. A method according to claim 1, wherein a capacitive coupler connects the conductive connection to the venous branch.

7. A method according to claim 1, wherein a detector circuit is provided on said conductive connection, said detector circuit being configured to perform said detecting of the value.

8. A method according to claim 1, wherein a generator circuit is provided on said conductive connection, said generator circuit being configured to perform said generating the potential difference.

9. A method in accordance with claim 1, wherein a detector circuit is configured to perform said detecting the value, said detector circuit being connected to the venous branch at first and second points, said first and second points being located on said at least one portion of the venous branch.

10. A method according to claim 9, wherein a first capacitive coupler connects the detector circuit to the venous branch at said first point, and a second capacitive coupler connects the detector circuit to the venous branch at said second point.

11. A method according to claim 1, wherein a generator circuit generates the potential difference, said generator circuit being connected to earth.

12. A device for monitoring a cardiovascular access during an extracorporeal blood treatment comprising:

a conductive connection arranged between a first passage point of an arterial branch of an extracorporeal blood circuit, and a second passage point of a venous branch of the extracorporeal blood circuit;

a voltage generator circuit configured to generate a potential difference between said first and second passage points when the extracorporeal blood circuit is connected to a patient through an arterial needle and a venous needle;

a detector circuit configured to detect a value of a quantity corresponding to an electric current along at least one section of the extracorporeal circuit, said at least one section of the extracorporeal circuit comprising;

a portion of the venous branch between the second passage point and the venous needle;

a portion of the arterial branch between the arterial needle and the first passage point; and

the conductive connection; and

a comparator circuit configured to compare the value to a reference range.

13. A device according to claim 12, comprising an extracorporeal blood circuit having a first point of an arterial branch located at the first passage point, and a second point of a venous branch located at the second passage point.

14. A device according to claim 13, wherein said second point is located between the venous needle and a bubble trap, said bubble trap being arranged along the venous branch.

15. A device according to claim 13, wherein said first point is located between the arterial needle and a peristaltic pump, said peristaltic pump being arranged on the arterial branch.

16. A device according to claim 12, wherein a capacitive coupler is arranged substantially on said first passage point.

17. A device according to claim 12, wherein a capacitive coupler is arranged substantially on said second passage point.

18. A device according to claim 16 or 17, wherein the capacitive coupler comprises at least one metal tube, said metal tube being wound around a respective portion of the extracorporeal blood circuit.

19. A device according to claim 12, wherein the detector circuit is arranged substantially on the conductive connection.

20. A device according to claim 12, wherein the voltage generator circuit is arranged substantially on the conductive connector.

21. A device according to claim 12, wherein the detector circuit is connected to the venous branch at a first connection point and a second connection point, said first and second connection points being located on said portion of the venous branch between the second passage point and the venous needle.

22. A device according to claim 12, wherein the voltage generator circuit is connected to earth.

23. A device according to claim 12, wherein the detector circuit is a voltage drop detector.

24. A device according to claim 12, wherein the comparator circuit is configured to output at least one control signal when the value is outside the reference range.

25. A device according to claim 12, further comprising at least one capacitive coupler, said at least one capacitive coupler being connected to the voltage generator circuit and the extracorporeal blood circuit.

26. A device according to claim 12, further comprising at least one capacitive coupler, said at least one capacitive coupler being connected to the detector circuit and the extracorporeal blood circuit.

27. A device according to claim 12, wherein the voltage generator circuit is connected to the extracorporeal blood circuit and the voltage generator circuit is also connected to earth.