Access disconnection systems and methods

• US 20030195453A1
• Filed: 04/10/2002
• Published: 10/16/2003
• Est. Priority Date: 04/10/2002
• Status: Active Grant

• Current Assignee: Baxter Healthcare SA (Baxter International Inc.), Baxter International Inc.
• Original Assignee: Baxter International Inc.
• Inventors: Han, James, Hartranft, Thomas P., Lasso, Angel, Kelly, Thomas D.
• Granted Patent: US 7,052,480 B2
• Time in Patent Office: Days
• US Class Current: 604/5.01
• CPC Class Codes: A61M 1/30 Single needle dialysis ; Reciprocating systems, alternately withdrawing blood from and returning it to the patient, e.g. single-lumen-needle dialysis or single needle systems for hemofiltration or pheresis
• 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 1/3659 Cannulae pertaining to extracorporeal circulation
• CPC Class Codes: A61M 1/3661 for haemodialysis
• CPC Class Codes: A61M 1/3669 Electrical impedance measurement of body fluids; transducers specially adapted therefor
• CPC Class Codes: A61M 2205/13 with means for the detection of operative contact with patient, e.g. lip sensor
• CPC Class Codes: Y10S 439/909 Medical use or attached to human body

Abstract

Apparatuses, devices, systems and methods for detecting access disconnection during medical therapy are provided. The present invention includes an electric circuit coupled to, for example, a blood circuit used during dialysis therapy. The electric circuit can be adapted to inject an electrical signal into the blood circuit such that changes in an electrical value in response to access disconnection, such as needle dropout or catheter drop-out, can be effectively detected.

Claims

1. A method of detecting access disconnection during an extracorporeal blood treatment, the method comprising the steps of:

coupling an extracorporeal blood system including a plurality of components to a patient with an extracorporeal blood circuit including a first blood line and a second blood line such that blood flows into, through and out of the patient along the extracorporeal blood circuit during treatment;

injecting an electrical signal into the extracorporeal blood circuit;

passing the electrical signal through a conductive connection between the first blood line and the second blood line thereby defining a loop that bypasses one or more components of the extracorporeal blood system coupled to the extracorporeal blood circuit; and

measuring a change in an electrical value in response to access disconnection.

2. The method of claim 1 wherein an electrical current is injected into the blood circuit.

3. The method of claim 1 wherein the change in the electrical value is measured in response to dislodgment of a needle in the patient that is coupled to a venous blood line.

4. The method of claim 1 wherein the change in the electrical value is measured in response to dislodgment of a needle in the patient that is coupled to an arterial blood line.

5. The method of claim 1 wherein the conductive connection includes a conductive material which defines a conductive path between the first blood line and the second blood line.

6. The method of claim 5 wherein the conductive connection is adapted to contact blood flowing through the first and second blood lines.

7. The method of claim 5 wherein the conductive connection is capacitively coupled to the first and second blood lines.

8. The method of claim 1 wherein the bypassed components are selected from the group consisting of a bubble trap, a blood pump, a blood treatment device, a dialysis machine and combinations thereof.

9. The method of claim 1 wherein the electrical value is selected from the group consisting of voltage, resistance, impedance, current, rates of changes thereof and combinations thereof.

10. An apparatus for detecting dislodgment of an access device inserted within a patient as blood flows through an extracorporeal blood circuit including a first blood line and a second blood line that connects the patient to an extracorporeal blood system including a plurality of components, the apparatus comprising:

an electrical signal device for injecting an electrical signal into the extracorporeal blood circuit;

a bypass device that includes a conductive connection between the first blood line and the second blood line thereby defining a loop along the extracorporeal blood circuit allowing the electrical signal to bypass one or more components of the extracorporeal blood system; and

a measuring device coupled to the extracorporeal blood circuit that is capable of measuring a change in an electrical value in response to dislodgment of the access device.

11. The apparatus of claim 10 wherein the electrical signal device comprises an induction coil.

12. The apparatus of claim 10 wherein the electrical signal device is capacitively coupled to the blood circuit.

13. The apparatus of claim 10 wherein the electrical signal device comprises an electrical contact in fluid and electrical communication with blood flowing through the blood circuit.

14. The apparatus of claim 10 further comprising an analyzer unit coupled to the measuring device that is capable of processing a signal derived from the measuring device allowing the change in electrical value to be detected and further processed.

15. The apparatus of claim 10 wherein the change in the electrical value is detected in response to dislodgment of a needle in the patient.

16. The apparatus of claim 10 wherein the conductive connection includes a conductive path in direct contact with blood flowing in the first and second blood lines.

17. The apparatus of claim 10 wherein the conductive connection is capacitively coupled to the first and second blood lines.

18. The apparatus of claim 10 wherein the measuring device includes an induction coil.

19. A method of detecting access disconnection during an extracorporeal blood treatment, the method comprising the steps of:

coupling an extracorporeal blood system including a plurality of components to a patient via an extracorporeal blood circuit including a first blood line and a second blood line allowing blood to flow into, through and out of the patient along the extracorporeal blood circuit during treatment;

injecting an electrical signal into the blood circuit through a direct conductive connection between a first contact point and a second contact point attached to the extracorporeal blood circuit and directly contacting the blood thereby defining a loop; and

measuring a change in an electrical value at a third contact point attached to the extracorporeal blood circuit in response to access disconnection.

20. The method of claim 19 wherein the direct conductive connection is formed between a pair of electrodes in direct contact with blood as it flows through the extracorporeal blood circuit.

21. The method of claim 19 wherein an induction coil is coupled to the extracorporeal blood circuit at the third contact point allowing the change in the electrical value to be measured.

22. The method of claim 19 wherein the third contact point includes an electrical contact attached to the blood circuit in fluid communication with the blood.

23. The method of claim 19 wherein the third contact point includes a capacitive coupler.

24. The method of claim 19 wherein the electrical value is selected from the group consisting of voltage, resistance, impedance, current, rate of changes thereof and combinations thereof.

25. The method of claim 19 wherein the change in electrical value is measured in response to dislodgment of a needle in the patient that is coupled to the extracorporeal blood circuit.

26. An apparatus for detecting dislodgment of an access device from a patient as blood flows through an extracorporeal blood circuit including a first blood line and a second blood line allowing connection of the patient to an extracorporeal blood system including a plurality of components, the apparatus comprising:

a direct conductive connection between a first contact point and a second contact point attached to the extracorporeal blood circuit through which an electrical signal can be injected into the blood circuit thereby defining a loop; and

a measuring device coupled to the extracorporeal blood circuit at a third contact point wherein the measuring device can be used to measure a change in an electrical value in response to dislodgment detection.

27. The apparatus of claim 26 wherein the direct conductive connection is formed between a pair of electrodes in direct contact with blood as it flows through the extracorporeal blood circuit.

28. The apparatus of claim 26 wherein an induction coil is coupled to the extracorporeal blood circuit at the third contact point allowing the change in the electrical value to be measured.

29. The apparatus of claim 26 wherein the third contact point includes an electrical contact attached to the blood circuit in fluid communication with the blood.

30. The apparatus of claim 26 wherein the third contact point includes a capacitive coupler attached to the blood circuit.

31. The apparatus of claim 26 wherein the electrical value is selected from the group consisting of voltage, resistance, impedance, current, rate of changes thereof and combinations thereof.

32. The apparatus of claim 26 wherein a change in impedance is detected in response to dislodgment of a needle in the patient that is coupled to the extracorporeal blood circuit.

33. A method of detecting access disconnection during an extracorporeal blood treatment, the method comprising the steps of:

coupling an extracorporeal blood system including a plurality of components to a patient via an extracorporeal blood circuit including a first blood line and a second blood line allowing blood to flow into, through and from the patient along the extracorporeal blood circuit during treatment;

injecting an electrical signal into the blood circuit at a first contact point thereby defining a loop; and

measuring a change in an electrical value using a direct conductive connection made between a second electrical contact point and a third electrical contact point along the loop in response to access disconnection.

34. The method of claim 33 wherein the direct conductive connection is formed between a pair of electrodes in direct contact with blood as it flows through the extracorporeal blood circuit.

35. The method of claim 33 wherein an induction coil is coupled to the extracorporeal blood circuit at the first contact point allowing the electric signal to be injected.

36. The method of claim 33 wherein the third contact point includes an electrical contact attached to the blood circuit in fluid communication with the blood.

37. The method of claim 33 wherein the third contact point includes a capacitive coupler attached to the blood circuit.

38. The method of claim 33 wherein the electrical value is selected from the group consisting of voltage, resistance, impedance, current, rate of changes thereof and combinations thereof.

39. The method of claim 33 wherein the change in electrical value is measured in response to dislodgment of a needle in the patient that is coupled to the extracorporeal blood circuit allowing blood to flow into, through and out of the patient.

40. An apparatus for detecting dislodgment of an access device from a patient as blood flows through an extracorporeal blood circuit which includes a first blood line and a second blood line allowing connection of the patient to an extracorporeal blood system including a plurality of components, the apparatus comprising:

an electrical signal device coupled to the extracorporeal blood circuit at a first contact point capable of injecting an electrical signal into the blood circuit thereby defining a loop; and

a direct conductive connection between a second contact point and a third contact point within the loop along which a change in an electrical value can be measured in response to dislodgment.

41. The apparatus of claim 40 wherein the direct conductive connection includes a pair of electrodes in direct contact with blood as it flows through the extracorporeal blood circuit.

42. The apparatus of claim 40 wherein an induction coil is coupled to the extracorporeal blood circuit at the third contact point.

43. The method of claim 40 wherein the third contact point includes an electrical contact attached to the blood circuit in fluid communication with the blood.

44. The method of claim 40 wherein the third contact point includes a capacitive coupler.

45. The method of claim 40 wherein the electrical value is selected from the group consisting of voltage, resistance, impedance, current, rate of changes thereof and combinations thereof.

46. The apparatus of claim 40 wherein the change in an electrical value is measured in response to dislodgment of a needle in the patient and coupled to the extracorporeal blood circuit.

47. A dialysis machine comprising a chassis having one or more connectors for connecting a patient to the dialysis machine via a blood circuit allowing blood to flow between the patient and the dialysis machine during dialysis therapy wherein a plurality of electrical contacts are connected to the blood circuit allowing detection of access disconnection using a direct conductive connection.

48. The dialysis machine of claim 47 wherein the direct conductive connection can be used to inject an electrical signal into the blood circuit thereby defining a loop allowing detection of access disconnection.

49. The dialysis machine of claim 48 wherein the direct conductive connection can be used to measure a change in an electrical value in response to access disconnection.

50. The dialysis machine of claim 48 wherein the direct conductive connection can be used to bypass the dialysis machine from the loop.

51. The dialysis machine of claim 47 wherein the direct conductive connection is made between a pair of electrical contacts in direct contact with blood as it flows through the blood circuit.

52. The dialysis machine of claim 47 wherein a controller is attached to at least one of the electrical contacts allowing processing of a signal indicative of a detectable change in an electrical value in response to access disconnection such that blood loss due to same can be minimized.

53. The dialysis machine of claim 52 wherein the signal can be processed allowing automatic termination of dialysis therapy.

54. The dialysis machine of claim 47 wherein the access disconnection is due to dislodgment of an access device inserted in the patient through which blood can flow along the blood circuit.

55. The dialysis machine of claim 54 wherein the access device is selected from the group consisting of a needle, a catheter, a venous needle and an arterial needle.

56. The dialysis machine of claim 47 wherein the electrical contacts are attached to the chassis of the dialysis machine.

57. A dialysis treatment center comprising:

a plurality of patient stations each at which dialysis therapy can be administered; and

one or more dialysis machines located at a respective patient station, at least one of the dialysis machines including a chassis having one or more connectors for connecting a patient to the dialysis machine via a blood circuit allowing blood to flow between the patient and the dialysis machine during dialysis therapy wherein a plurality of electrical contacts are connected to the blood circuit allowing detection of access disconnection using a direct conductive connection.

58. The dialysis treatment center of claim 57 wherein the direct conductive connection can be used to inject an electrical signal into the blood circuit thereby defining a loop allowing detection of access disconnection.

59. The dialysis treatment center of claim 58 wherein the direct conductive connection can be used to measure a change in an electrical value in response to access disconnection.

60. The dialysis treatment center of claim 58 wherein the direct conductive connection can be used to bypass the dialysis machine from the loop.

61. The dialysis treatment center of claim 57 wherein the direct conductive connection is made between a pair of electrical contacts in direct contact with blood as it flows through the blood circuit.

62. The dialysis treatment center of claim 57 wherein a controller is attached to at least one of the electrical contacts allowing processing of a signal indicative of a detectable change in an electrical value in response to access disconnection such that blood loss due to same can be minimized.

63. The dialysis treatment center of claim 62 wherein the signal can be processed allowing automatic termination of dialysis therapy.

64. The dialysis treatment center of claim 62 wherein the signal can be processed to activate an alarm upon detection of access disconnection.

65. The dialysis treatment center of claim 62 wherein the patient and/or medical staff can be alerted to take responsive actions in response to the alarm.

66. The dialysis treatment center of claim 57 wherein the dialysis therapy is selected from the group consisting of hemodialysis, hemofiltration, hemodiafiltration and continuous renal replacement.

67. The dialysis treatment center of claim 57 wherein the access disconnection is due to dislodgment of an access device inserted in the patient through which blood can flow.

68. The dialysis treatment center of claim 67 wherein the access device is selected from the group consisting of a needle, a catheter, a venous needle and an arterial needle.

69. An inductive coupling device comprising:

a first member and a second member movably attached to the first member at an end allowing for displacement of the first member and the second member into an open arrangement and a closed arrangement; and

an induction coil placed around at least a portion of at least one of the first and second members.

70. The inductive coupling device of claim 69 wherein the inductive coupling device includes a hinge attached to the first member and the second member at the end.

71. The inductive coupling device of claim 69 wherein the first and second members are composed of a material that has a magnetic permeability in an amount effective to converge an electromagnetic field into the induction coil.

72. A method for injecting an electrical signal in a fluid passing through a fluid conduit, the method comprising the steps of:

providing an inductive coupler including a first member and a second member movably attached to the first member at an end allowing for displacement of the first member and the second member into an open arrangement and a closed arrangement wherein an induction coil is attached to the inductive coupler;

placing the inductive coupler around the fluid conduit in the open arrangement;

displacing the first member and the second member to the closed arrangement thereby securing the inductive coupler to the fluid conduit; and

using the inductive coupler to inject an electrical signal in the fluid.

73. The method of claim 72 wherein a hinge is used to movably attach the first member to the second member.

74. The method of claim 72 wherein the first and second members can direct an electromagnetic field to the induction coil allowing injection of the electrical signal.

75. The method of claim 72 wherein the fluid comprises blood passing through an extracorporeal blood circuit connecting a patient to an extracorporeal blood system.

76. The method of claim 72 wherein the electrical signal comprises a current.

77. A method for detecting a change in an electrical value as fluid passes through a fluid conduit of a fluid circuit, the method comprising the steps of:

providing a coupling device including a first member and a second member movably attached to the first member at a first end allowing for displacement of the first member and the second member into an open arrangement and a closed arrangement wherein an induction coil is attached to the coupling device;

placing the coupling device with the induction coil around the fluid conduit in the open arrangement;

displacing the first member and the second member to the closed arrangement thereby securing the induction coil to the fluid conduit; and

using the induction coil to measure the change in electrical value as the fluid passes through the fluid conduit with an electrical signal passing therein.

78. The method of claim 77 wherein a hinge is used to movably attach the first member to the second member.

79. The method of claim 77 wherein the coupling device can direct an electromagnetic field to the induction coil allowing measurement of a change in the electrical value.

80. The method of claim 77 wherein the fluid comprises blood passing through an extracorporeal blood circuit that couples a patient to an extracorporeal blood system.