ELECTROMAGNETIC INDUCTION ACCESS DISCONNECT SENSOR

• US 20100022935A1
• Filed: 07/25/2008
• Published: 01/28/2010
• Est. Priority Date: 07/25/2008
• Status: Active Grant

• Current Assignee: Baxter Healthcare SA (Baxter International Inc.), Baxter International Inc.
• Original Assignee: Baxter Healthcare SA (Baxter International Inc.), Baxter International Inc.
• Inventors: Muller, Matthew R.
• Granted Patent: US 8,114,043 B2
• Time in Patent Office: Days
• US Class Current: 604/6.40
• CPC Class Codes: A61M 1/3653 Interfaces between patient blood circulation and extra-corporal blood circuit
• CPC Class Codes: A61M 1/3655 Arterio-venous shunts or fistulae
• CPC Class Codes: A61M 1/3656 Monitoring patency or flow at connection sites; Detecting disconnections
• CPC Class Codes: A61M 1/3661 for haemodialysis
• CPC Class Codes: A61M 2205/13 with means for the detection of operative contact with patient, e.g. lip sensor
• CPC Class Codes: A61M 2205/3561 local, e.g. within room or hospital
• CPC Class Codes: A61M 2205/3569 sublocal, e.g. between console and disposable
• CPC Class Codes: A61M 2205/3592 using telemetric means, e.g. radio or optical transmission

Abstract

A connection of a patient'"'"'s vascular system to an extracorporeal blood treatment machine is monitored to ensure the patient'"'"'s safety during a procedure. The procedure may be hemodialysis, apheresis, plasmapheresis, a coronary by-pass operation, or other procedure. To ensure safe electrical connection, a contact and a return are connected via a conductive connection into the extracorporeal blood circuit. A current is then generated between the contact and the return and is monitored by a non-contact sensor near an access site of the patient. If the current or other quantity related to the current changes significantly, a signal is sent to the machine or a controller to notify a caregiver or a medical professional. The signal may also be sent to immediately stop a blood pump or other component of the machine.

Claims

1. A method for detecting an access disconnect, the method comprising:

generating a time-varying electric current in a vascular system of a patient and an extracorporeal blood circuit with conductive connections in at least one of the vascular system of the patient and the extracorporeal blood circuit;

monitoring a value of a quantity corresponding to the electric current with a non-contact sensor atop an access site of the patient, near the vascular system of the patient, or near tubing of the extracorporeal blood circuit;

comparing the value with preselected limits for the value; and

sending a signal if the value exceeds the preselected limits.

2. The method according to claim 1, further comprising sounding an alarm or shutting off a blood pump if the signal exceeds the preselected limits.

3. The method according to claim 1, wherein the non-contact sensor detects the value using electrical capacitance, inductance, or magnetic coupling.

4. The method according to claim 1, wherein the current is generated using at least one direct contact in the extracorporeal blood system.

5. The method according to claim 1, further comprising placing at least one of the conductive connections between the patient and an inlet to a dialyzer.

6. The method according to claim 1, further comprising undergoing an extracorporeal blood treatment selected from the group consisting of hemodialysis, apheresis, and plasmapheresis.

7. A method for detecting an access disconnect, the method comprising:

generating a time-varying electric current in a vascular system of a patient and an extracorporeal blood circuit with at least one conductive connection;

monitoring a value of a quantity corresponding to the electric current with a non-contact sensor atop an access site of the patient, near the vascular system of the patient, or near tubing of the extracorporeal blood circuit;

comparing the value with preselected limits for the value; and

sending a signal if the value exceeds the preselected limits.

8. The method according to claim 7, wherein the at least one conductive connection comprises two conductive connections on the arterial side of the dialyzer.

9. The method according to claim 7, further comprising monitoring current in dialysate tubing of the dialyzer.

10. The method according to claim 7, further comprising returning current through an isolated ground connected to a current generator and the at least one of the contacts.

11. The method according to claim 7, wherein the at least one conductive connection comprises a single conductive connection on a venous side of the dialyzer and wherein the conductive connection is completed via a ground connection between the single conductive connection and the patient.

12. The method according to claim 7, wherein the step of generating is conducted periodically rather than continuously.

13. An access disconnect system, comprising:

a conductive connection between a vascular system of a patient and a hemodialysis machine, the conductive connection comprising first and second conductive contacts in tubing leading to and from the hemodialysis machine;

a source of time-varying electric current connected to said first conductive contact;

a non-contact sensor for positioning atop an access site of the patient, near the vascular system of the patient, or near the tubing, the non-contact sensor configured for detecting a value of a quantity corresponding to the current; and

a transmitter operably connected to the non-contact sensor for sending a signal indicative of the value to a controller of the hemodialysis machine.

14. The access disconnect system according to claim 13, wherein the signal is selected from the group consisting of a signal indicating the quantity or a signal indicating whether the quantity is within preselected limits.

15. The access disconnect system according to claim 13, wherein said first conductive contact is located in tubing upstream from the hemodialysis machine.

16. The access disconnect system according to claim 13, wherein the sensor is selected from the group consisting of a hall-effect sensor, an induction coil, a capacitive sensor and an induction sensor.

17. The access disconnect system according to claim 13, wherein the time varying electric current is 10 microamperes or less.

18. An access disconnect system, comprising:

a conductive connection between a vascular system of a patient and a hemodialysis machine, the conductive connection comprising first and second conductive contacts in tubing leading to the hemodialysis machine;

a source of time-varying electric current connected to said first conductive contact;

a non-contact sensor for positioning atop an access site of the patient, near the vascular system of the patient, or near the tubing, the non-contact sensor configured for detecting a value of a quantity corresponding to the current; and

a transmitter operably connected to the non-contact sensor for sending a signal indicative of the value to a controller of the hemodialysis machine.

19. The access disconnect system according to claim 18, wherein the contacts are located in tubing on an arterial side of the hemodialysis machine.

20. The access disconnect system according to claim 18, further comprising a line clamp on tubing leading to and from the hemodialysis machine.

21. The access disconnect system according to claim 18, further comprising a current sensing circuit on dialysate tubing connected to the hemodialysis machine.

22. The access disconnect system according to claim 18, further comprising a current impedance circuit on dialysate tubing connected to the hemodialysis machine.