ENHANCED SIGNAL DETECTION FOR ACCESS DISCONNECTION SYSTEMS

• US 20080065006A1
• Filed: 02/16/2007
• Published: 03/13/2008
• Est. Priority Date: 04/10/2002
• Status: Active Grant

• Current Assignee: Baxter Healthcare SA (Baxter International Inc.)
• Original Assignee: Baxter Healthcare SA (Baxter International Inc.), Baxter International Inc.
• Inventors: Hartranft, Thomas, Wariar, Ramesh, Roger, Rodolfo, Lamberson, George, Lasso, Angel
• Granted Patent: US 10,155,082 B2
• Time in Patent Office: Days
• US Class Current: 604/65
• CPC Class Codes: A61M 1/16 with membranes
• CPC Class Codes: A61M 1/34 Filtering material out of the blood by passing it through a membrane, i.e. hemofiltration or diafiltration
• CPC Class Codes: A61M 1/3413 Diafiltration
• CPC Class Codes: A61M 1/3653 Interfaces between patient blood circulation and extra-corporal blood circuit
• CPC Class Codes: A61M 1/3656 Monitoring patency or flow at connection sites; Detecting disconnections
• CPC Class Codes: A61M 2205/13 with means for the detection of operative contact with patient, e.g. lip sensor
• CPC Class Codes: A61M 2205/3569 sublocal, e.g. between console and disposable
• CPC Class Codes: A61M 2205/3592 using telemetric means, e.g. radio or optical transmission
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• CPC Class Codes: A61M 39/10 Tube connectors; Tube couplings A61M39/02 takes precedence; connecting needles to syringes or hubs A61M5/34; connecting catheter tubes to hubs A61M25/0014
• CPC Class Codes: A61M 5/16831 Monitoring, detecting, signalling or eliminating infusion flow anomalies low-level float-valves causing cut-off A61M5/40; indicating or recording presence, absence or direction of flow in general G01P13/0066
• CPC Class Codes: G01N 27/07 Construction of measuring vessels; Electrodes therefor
• CPC Class Codes: G01N 27/10 Investigation or analysis specially adapted for controlling or monitoring operations or for signalling
• CPC Class Codes: G01N 33/49 Blood chemical methods for determining blood cell populations G01N33/5094; chemical analysis of blood groups or blood types G01N33/80

Abstract

An access disconnection system includes an extracorporeal circuit; first and second contacts provided in the extracorporeal circuit; a current source communicating with the first contact and configured to generate a current within fluid flowing through the extracorporeal circuit; and an apparatus positioned to apply a signal at multiple points along a path from the extracorporeal circuit, the signals tending to prevent at least a portion of the current from traveling through a ground path in parallel to the extracorporeal circuit.

Claims

1. An access disconnection system comprising:

an extracorporeal circuit;

first and second contacts provided in the extracorporeal circuit;

a signal source communicating with the first contact and configured to generate a signal within fluid flowing through the extracorporeal circuit;

an isolation ground in communication with the second contact; and

an apparatus positioned to apply a voltage at multiple points along a path from the extracorporeal circuit to earth ground, the voltages tending to prevent at least a portion of the signal from traveling through earth ground to the isolation ground.

2. The access disconnection system of claim 1, wherein the signal source includes a voltage source and a resister positioned such that the signal is a current signal.

3. The access disconnection system of claim 1, wherein the apparatus is an amplifier positioned to duplicate the voltage at the multiple points along the path.

4. The access disconnection system of claim 1, which includes a processor and signal conditioning positioned between the signal source and the processor, the signal being a first signal and which includes a second signal conditioned by the signal conditioning and sent to the processor for determining a patient disconnection from the extracorporeal circuit.

5. The access disconnection system of claim 4, wherein the signal conditioning includes at least one of:

an amplifier and an analog to digital converter.

6. The access disconnection system of claim 4, wherein the second signal is indicative of an impedance of the extracorporeal circuit.

7. The access disconnection system of claim 4, wherein the second signal is a digitized signal.

8. The access disconnection system of claim 1, wherein the path from the extracorporeal circuit to earth ground includes at least one of:

a dialyzer and a dialysate flow path.

9. The access disconnection system of claim 1, wherein the extracorporeal circuit produces at least one impedance selected from the group consisting of:

(i) impedance of blood in a tube segment between the first contact and a pump operable with the extracorporeal circuit;

(ii) impedance of blood in a pump tube segment;

(iii) impedance of blood in a tube segment between the pump and a dialyzer operable with the extracorporeal circuit;

(iv) impedance of blood in a tube segment between the dialyzer and the second contact;

(v) impedance of blood in a tube segment between the second contact and a second patient access point; and

(vi) impedance of blood in a tube segment between a first patient access point and the first contact.

10. The access disconnection system of claim 1, wherein the first contact is placed in an arterial path of the extracorporeal circuit and the second contact is placed in a venous path of the extracorporeal circuit.

11. The access disconnection system of claim 1, wherein the apparatus is a first apparatus, the voltage is a first voltage, the path is a first path, and which includes a second apparatus configured to apply a second voltage at multiple points along a second path of the extracorporeal circuit, the second voltages tending to prevent at least a portion of the signal from traveling through a pump tube segment of the extracorporeal circuit.

12. The access disconnection system of claim 11, wherein the second apparatus is an amplifier positioned to duplicate a voltage at the multiple points along the second path.

13. The access disconnection system of claim 11, wherein the first and second voltages are at least substantially the same.

14. The access disconnection system of claim 11, wherein the second voltage applied at multiple points along the second path tends to shunt more of the signal through a patient access portion of the extracorporeal circuit.

15. An access disconnection system comprising:

an extracorporeal circuit;

first and second contacts provided in the extracorporeal circuit;

a current source communicating with at least one of the first and second contacts and configured to generate a current within fluid flowing through the extracorporeal circuit; and

an apparatus positioned to apply a signal at multiple points along a path in parallel to the extracorporeal circuit, the signals tending to prevent at least a portion of the current from traveling through the parallel path.

16. The access disconnection system of claim 15, wherein the parallel path includes a path from earth ground to an isolation ground of the system.

17. The access disconnection system of claim 15, wherein the current source includes a voltage source in series with a resister.

18. The access disconnection system of claim 15, wherein the signals tend to prevent the portion of the current from traveling through the parallel path even after a patient access disconnection.

19. An access disconnection system comprising:

an extracorporeal circuit;

first and second contacts provided in the extracorporeal circuit;

a signal source communicating with at least one of the first and second contacts and configured to generate a signal within fluid flowing through the extracorporeal circuit; and

an apparatus positioned to apply a potential at multiple points along a path in parallel to the extracorporeal circuit, the applied potentials creating a virtual open circuit between the multiple points.

20. The access disconnection system of claim 19, wherein the potentials tend to prevent at least a portion of the signal from traveling through a ground path in parallel to the extracorporeal circuit.

21. An access disconnection system comprising:

an extracorporeal circuit;

a dialysate circuit;

a first sensing apparatus configured to sense a first signal indicative of a first impedance produced by fluid flowing through the extracorporeal circuit; and

a second sensing apparatus configured to sense a second signal indicative of a second impedance produced by fluid flowing through the dialysate circuit.

22. The access disconnection system of claim 21, which includes first and second contacts provided in the extracorporeal circuit and a signal source communicating with at least one of the first and second contacts and configured to generate a signal within fluid flowing through the extracorporeal circuit.

23. The access disconnection system of claim 21, wherein the signal generated by the signal source is split into the first and second signals portions.

24. The access disconnection system of claim 23, wherein the second signal portion has at least one characteristic selected from the group consisting of:

(i) being in parallel with the first signal portion;

(ii) provided in a ground loop; and

(iii) being indicative of a patient'"'"'s electrical potential relative to ground.

25. The access disconnection system of claim 21, which includes a controller in communication with the first and second sensing apparatuses, the controller configured to monitor the first signal only for an access disconnection if the second signal is below a threshold.

26. The access disconnection system of claim 21, which includes a controller in communication with the first and second sensing apparatuses, the controller configured to monitor the second signal only for an access disconnection if the second signal is above a threshold.

27. The access disconnection system of claim 21, which includes a controller in communication with the first and second sensing apparatuses, the controller configured to monitor the first and second signals for an access disconnection.

28. The access disconnection system of claim 21, wherein at least one of the first and second impedances is a lumped impedance.

29. The access disconnection system of claim 21, wherein the fluid flowing through the extracorporeal circuit is at least substantially blood and the fluid flowing through the dialysis circuit is at least substantially dialysate.

30. An access disconnection system comprising:

an extracorporeal circuit;

arterial and venous contacts provided in the extracorporeal circuit;

arterial and venous patient access apparatuses;

a signal source communicating with at least one of the arterial and venous contacts and configured to generate a signal within fluid flowing through the extracorporeal circuit;

a sensing apparatus configured to sense a first portion of the signal indicative of a first impedance produced by fluid flowing through the extracorporeal circuit; and

wherein at least one of the arterial and venous contacts is placed close enough to a respective arterial and venous patient access apparatus such that a second portion of the signal indicative of a second impedance produced by fluid flowing through a parallel ground loop can be ignored.

31. The access disconnection system of claim 30, wherein at least one of the first and second impedances is a lumped impedance.

32. The access disconnection system of claim 30, wherein the at least one of the arterial and venous contacts is placed close enough to the respective arterial and venous patient access apparatus, such that a majority of the first portion of the signal flows through the arterial and venous patient access apparatus.

33. An access disconnection system comprising:

an extracorporeal circuit;

a dialysate circuit;

an apparatus positioned to apply a potential at multiple points along the dialysate circuit, the applied potentials creating a virtual open circuit between the multiple points;

an electrical path extending from the multiple points, to the extracorporeal circuit; and

a device configured to bring a patient to ground, such that when the patient is connected to the extracorporeal circuit and to grounding device, the electrical path extends from the extracorporeal circuit to ground.

34. The access disconnection system of claim 33, wherein the ground is one of an earth ground and an isolation ground.

35. The access disconnection system of claim 33, which includes a sensing apparatus placed in the electrical path and a signal source configured to induce a signal into the electrical path, the sensing apparatus sensing the signal, the signal indicative of an impedance in the electrical path.

36. The access disconnection system of claim 35, wherein impedance increases upon an access disconnection of the patient from the extracorporeal circuit, and electronics configured to cause an alarm when the sensing apparatus senses an increase of impedance indicative of an access disconnection of the patient from the extracorporeal circuit.

37. The access disconnection system of claim 33, wherein the grounding device is configured to connect removeably from the patient.

38. The access disconnection system of claim 33, wherein the multiple points along the dialysate circuit include reuseable conductive couplers.

39. An access disconnection system comprising:

an extracorporeal circuit;

a dialysate circuit;

an electrical path extending from the dialysate circuit to the extracorporeal circuit;

a signal source configured to induce a signal into the electrical path from the signal source; and

a sensing apparatus configured to sense the signal, the signal indicative of an impedance of the electrical path.

40. The access disconnection system of claim 39, which includes a device configured to bring a patient to ground, such that when the patient is connected to the extracorporeal circuit and to grounding device, the electrical path extends from the extracorporeal circuit to ground.

41. The access disconnection system of claim 39, which includes electronics configured to cause an alarm when the sensing apparatus senses an increase of impedance due to a disconnection of a patient from the extracorporeal circuit.

42. The access disconnection system of claim 41, wherein the increase of impedance is due to the signal being shunted through a larger impedance path of the extracorporeal circuit upon the access disconnection.

43. The access disconnection system of claim 39, which includes an apparatus positioned to apply a potential at multiple points along the dialysate circuit, the applied potential creating a virtual open circuit between the multiple points.

44. The access disconnection system of claim 43, wherein at least one of the signal source and sensing apparatus communicates with the electrical path at the dialysate circuit between the multiple points and the extracorporeal circuit.

45. An access disconnection system comprising:

an extraporaneous circuit;

a dialysate circuit;

a signal source configured to induce a signal into the dialysate circuit;

a sensing apparatus configured to sense the signal, the signal indicative of at lease one electrical impedance in the extracorporeal circuit and at least one electrical impedance in the dialysate circuit.

46. The access disconnection system of claim 45, which includes an apparatus positioned to apply a potential at multiple points along the dialysate circuit, the applied potential creating a virtual open circuit between the multiple points.

47. The access disconnection system of claim 45, which includes an electrical path extending from the signal source located at one side of the multiple points, through the extracorporeal circuit, through a path to earth ground, through the dialysate circuit located at a second side of the multiple points, to isolated ground.

48. An access disconnection system comprising:

a protector module including at least one line clamp and a wireless receiver, the protector module configured to be positioned with respect to a blood treatment machine so as to be able to at least partially occlude at least one of an arterial line and a venous line using the at least one line clamp upon a signal received by the wireless receiver; and

a detector module including a sensor and a wireless emitter, the detector module configured to be prositioned with respect to the arterial and venous lines so as to be able to sense a disconnection of one of the arterial and venous lines from a patient and send the signal to the wireless receiver of the protector module via the wireless emitter.

49. The access disconnection system of claim 48, wherein at least one of:

(i) the protector module is removably attachable to the blood treatment machine, and (ii) the detector module is releasably attachable to the arterial and venous lines.

50. The access disconnection system of claim 48, wherein the sensor of the detector module includes at least one of:

(i) a set of conductors contacting fluid flowing through the arterial and venous lines;

(ii) a signal source configured to inject a signal into the fluid within at least one of the arterial and venous lines;

(iii) a sensing apparatus configured to detect a change in impedance of the fluid within at least one of the arteral and venous lines;

(iv) signed conditioning; and

(v) logic control.