Access disconnection systems and methods

• US 20030195454A1
• 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: Wariar, Ramesh, Han, James, Falkvall, Thore, Lamberson, George, Hartranft, Thomas P.
• Granted Patent: US 7,138,088 B2
• Time in Patent Office: Days
• US Class Current: 604/5.01
• 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 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

Apparatuses, devices, systems and methods for detecting access disconnection are provided. The present invention includes electrical contacts in fluid and electrical communication with a fluid passing between a patient and a medical system during therapy. In this regard, the present invention can use a direct-contact measurement to detect access disconnection, such as dislodgment of an access device from the patient through which fluid can flow during therapy including, for example, medication delivery, dialysis therapy and the like.

Claims

1. A medical device capable of detecting an access disconnection during medical therapy comprising a plurality of electrical contacts in fluid contact with a fluid and spaced apart from an access device insertable within a patient such that the electrical contacts can be used to detect a change in an electrical value responsive to access disconnection as the fluid flows between the patient and a fluid system connected to the patient via the access device.

2. The medical device of claim 1 wherein the electrical contacts can be used to detect blood loss due to dislodgment of at least one of a catheter, a venous needle and an arterial needle each insertable within the patient during dialysis therapy.

3. The medical device of claim 1 wherein the electrical contacts can be used to detect fluid loss due to dislodgment of a single access device insertable within the patient during medication delivery.

4. The medical device of claim 1 wherein the fluid system can be adapted to administer medical therapy selected from the group consisting of medication delivery, drug delivery, blood delivery, intravenous infusion and dialysis therapy including hemodialysis, hemodiafiltration, hemofiltration and continuous renal replacement therapy.

5. An apparatus for detecting dislodgment of an access device inserted into a patient during medical therapy comprising:

a blood circuit connecting the patient to an extracorporeal blood system wherein the blood circuit includes a blood tubing set having a first tube member connected to a first access device and a second tube member connected to a second access device and wherein the first access device and the second access device are each insertable within the patient such that blood flows between the patient and the extracorporeal blood system via the blood circuit;

a pair of electrical contacts in fluid contact with the blood and spaced apart from at least one of the first access device and the second access device; and

a controller in electrical contact with the pair of electrical contacts and capable of imparting an electrical signal passing between the pair of electrical contacts, measuring an electrical value associated with the electrical signal, and detecting a change in the electrical value due to dislodgment of at least one of the first access device and the second access device.

6. The apparatus of claim 5 wherein the pair of electrical contacts includes a first electrode and a second electrode such that the first electrode is coupled to the first tube member and the second electrode is coupled to the second tube member.

7. The apparatus of claim 5 wherein the pair of electrical contacts includes a first electrode coupled to the blood tubing set and a second electrode attached to the patient.

8. The apparatus of claim 5 wherein the first access device comprises a venous needle and the second access device comprises an arterial needle.

9. The apparatus of claim 5 wherein the electrical signal is generated from a constant current source associated with the controller and injected through at least one of the electrical contacts.

10. The apparatus of claim 9 further comprising a third electrical contact positioned along the blood circuit between the pair of electrical contacts and the extracorporeal blood system allowing the electrical signal to bypass one or more components of the extracorporeal blood system that are coupled to the blood circuit.

11. The apparatus of claim 5 wherein the apparatus comprises an electrical contact coupling device capable of securing at least one of the electrical contacts to a dialysis machine of the blood system through which the blood tubing set can be coupled to the dialysis machine.

12. The apparatus of claim 5 wherein the controller is capable of processing a signal from one of the electrical contacts in response to an impedance change due to dislodgment of a needle during dialysis therapy such that blood loss from the dislodgment can be monitored and controlled.

13. The apparatus of claim 5 wherein the controller is capable of measuring a change in voltage allowing detection of an impedance change in response to dislodgment as the blood passes through the blood circuit.

14. The apparatus of claim 13 wherein the controller is capable of correcting for a change in baseline impedance due to variations in blood characteristics during dialysis therapy.

15. An apparatus for detecting dislodgment of a single access device insertable within a patient to administer medical therapy comprising:

a tube member connecting the patient to a fluid system via the single access device wherein the fluid system contains a fluid that can flow between the patient and the fluid system; and

a first electrode connected to the tube member in fluid contact with the fluid and a second electrode attached to the patient in proximity to the single access device such that the first electrode and the second electrode can be used to detect a change in an electrical value due to dislodgment of the single access device as the fluid flows between the patient and the fluid system having an electrical signal passing therein.

16. The apparatus of claim 15 wherein the electrical signal is generated from a constant current source of a controller coupled to the electrodes allowing the electrical signal to be injected into the fluid.

17. The apparatus of claim 16 wherein the controller is capable of measuring a change in voltage allowing detection of an impedance change in response to dislodgment of the single access device.

18. The apparatus of claim 15 wherein the fluid system is selected from the group consisting of a medication delivery system, a medical solution delivery system, a drug delivery system, an intravenous infusion system and an extracorporeal system including a blood delivery system, a hemodialysis system, a hemofiltration system, a hemodiafiltration system and a continuous renal replacement system.

19. 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;

a pair of electrical contacts connected to the blood circuit in fluid contact with the blood; and

a controller for imparting an electrical signal that passes between the pair of electrical contacts and capable of detecting a change in an electrical value associated with the electrical signal in response to access disconnection of the blood circuit.

20. The dialysis machine of claim 19 wherein the access disconnection is due to dislodgment of an access device inserted in the patient through which blood can flow.

21. The dialysis machine of claim 20 wherein the access device is selected from the group consisting of a needle, a venous needle and a catheter.

22. The dialysis machine of claim 19 wherein the electrical contacts are attached to the chassis of the dialysis machine.

23. The dialysis machine of claim 19 wherein the electrical signal is generated from a constant current source of a controller coupled to the electrical contact pair allowing it to be injected into the blood.

24. The dialysis machine of claim 23 wherein the controller is capable of processing a signal derived from a detectable change in impedance such that the blood loss due to the dislodgment of a needle during dialysis therapy can be monitored and controlled.

25. The dialysis machine of claim 23 wherein the controller is capable of correcting for a change in baseline impedance that can be used to detect an impedance change in response to access disconnection.

26. A dialysis treatment center comprising:

a plurality of patient stations each at which dialysis therapy can be administered to one or more patients;

one or more dialysis machines located at a respective patient station, one or more of the dialysis machines 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; and

a pair of electrical contacts connected to the blood circuit in fluid contact with the blood allowing detection of a change in an electrical value in response to disconnection of at least one of the connectors as the blood flows through the blood circuit.

27. The dialysis treatment center of claim 26 wherein the dialysis therapy is selected from the group consisting of hemodialysis, hemofiltration, continuous renal replacement and combinations thereof.

28. The dialysis treatment center of claim 26 wherein the access disconnection is due to dislodgment of an access device inserted in the patient through which blood can flow.

29. The dialysis treatment center of claim 28 wherein the access device is selected from the group consisting of a needle, a catheter, a venous needle and an arterial needle.

30. The dialysis treatment center of claim 26 wherein the electrical signal is generated from a constant current source of a controller coupled to the electrical contact pair allowing the electrical signal to be injected into the blood.

31. The dialysis treatment center of claim 26 wherein the controller is capable of processing a signal derived from a detectable change in impedance such that blood loss due to the dislodgment of an access device during dialysis therapy can be monitored and controlled.

32. The dialysis treatment center of claim 26 wherein the signal can be processed to activate an alarm upon detection of access disconnection.

33. The dialysis of claim 32 wherein the dialysis machine can be adapted to automatically terminate dialysis therapy in response to the alarm.

34. The dialysis of claim 32 wherein the patient and/or medical care personnel can be alerted, allowing responsive actions to be taken in response to the alarm.

35. A method of detecting dislodgment of an access device during medical therapy comprising the steps of:

connecting a patient to a fluid circuit having a pair of electrical contacts each coupled to a fluid circuit in fluid contact with fluid that flows through the fluid circuit;

passing an electrical signal through the fluid via the pair of electrical contacts thereby defining a loop along which an electrical value can be measured; and

monitoring the electrical value and detecting a disconnection between the patient and the fluid circuit based on a change in the electrical value.

36. The method of claim 35 wherein the pair of electrical contacts includes a first electrode and a second electrode such that the first electrode and the second electrode are each coupled to a respective tube member through which the fluid flows within the blood circuit.

37. The method of claim 35 wherein a constant current is passed through the fluid via the pair of electrical contacts until dislodgment of the access device occurs.

38. The method of claim 35 wherein a change in voltage can be measured to detect impedance changes in response to dislodgment of the access device.

39. The method of claim 35 further comprising correcting for changes in baseline impedance that can be used to detect an impedance change in response to dislodgment.

40. A method of detecting dislodgment of an access device during dialysis therapy comprising the steps of:

connecting a patient to a blood circuit having a pair of electrical contacts each coupled to a blood circuit in fluid contact with blood that flows through the blood circuit;

passing an electrical signal through the blood via the pair of electrical contacts thereby defining a loop along which an electrical value can be measured; and

detecting a disconnection between the patient and the blood circuit in response to a change in the electrical value.

41. The method of claim 40 wherein the pair of electrical contacts includes a first electrode and a second electrode such that the first electrode and the second electrode are each coupled to a respective tube member through which the blood flows within the blood circuit.

42. The method of claim 40 wherein a constant current is passed through the blood via the pair of electrical contacts until dislodgment occurs.

43. The method of claim 40 further comprising coupling a third electrical contact to the blood circuit between the pair of electrical contacts and one or more components of the dialysis system;

and causing the electrical signal to bypass one or more of the components of the dialysis system.

44. The method of claim 40 wherein a change in voltage is measured to detect impedance changes during dialysis therapy.

45. The method of claim 40 further comprising correcting for changes in baseline impedance.

46. The method of claim 45 wherein the baseline impedance changes are due to a variations in blood characteristics during dialysis therapy.

47. The method of claim 40 wherein the access device is selected from group consisting of a needle, a catheter, a venous needle and an arterial needle.

48. A method of detecting access disconnection during dialysis therapy comprising the steps of:

connecting a patient to a blood circuit having a pair of electrical contacts each coupled to a blood circuit in fluid contact with blood that flows through the blood circuit;

passing an electrical signal through the blood via the pair of electrical contacts thereby defining a loop along which an electrical value can be measured;

coupling a third electrical contact to the blood circuit between the pair of electrical contacts and one or more components of a dialysis system connected to the blood circuit;

causing the electrical signal to bypass one or more of the components of the dialysis system; and

detecting a disconnection between the patient and the blood circuit in response to a change in the electrical value.

49. The method of claim 48 wherein an equalization potential is applied between the third electrical contact and one of the electrical contacts from the electrical contact pair equal in value to a potential applied between the pair of electrical contacts.

50. The method of claim 48 wherein the third electrical contact is attached to the blood circuit in fluid contact with the blood.

51. The method of claim 48 wherein the access device is selected from the group consisting of a needle, an arterial needle, a venous needle, and a catheter.

52. The method claim 48 wherein blood loss due to access disconnection can be minimized in response to a detectable impedance change due to dislodgment of the access device from the patient.

53. A method of controlling blood loss due to dislodgment of an access device inserted within a patient during medical therapy comprising the steps of:

connecting a patient to a blood circuit having a pair of electrical contacts in fluid contact with blood as it flows through the blood circuit;

passing an electrical signal through the blood via the electrical contacts thereby defining a loop along the blood circuit allowing an electrical value to be measured;

detecting a disconnection between the patient and the blood circuit in response to a change in the electrical value;

producing a signal based on the detectable change in the electrical value; and

processing the signal to minimize blood loss from the patient due to the disconnection.

54. The method of claim 53 wherein the signal is processed to activate an alarm which can trigger automatic termination of dialysis therapy.

55. The method of claim 53 wherein the signal is processed to shut-off a blood pump associated with a dialysis system.

56. The method of claim 53 wherein the signal is processed to activate a venous line clamp of a dialysis system.

57. The method of claim 53 wherein a change in voltage can be measured to detect an impedance change in response to dislodgment.

58. The method of claim 57 further comprising correcting for changes in baseline impedance that can be used to detect the impedance change.

59. A method of providing dialysis therapy to a patient comprising the steps of:

connecting a patient to a dialysis system via a blood circuit having a pair of electrical contacts coupled to the blood circuit in fluid contact with blood as it flows through the blood circuit;

passing an electrical signal through the blood via the pair of electrical contacts thereby defining a loop along which an electrical value can be measured; and

detecting a disconnection between the patient and the blood circuit in response to a measurable change in the electrical value during dialysis therapy.

60. The method of claim 59 wherein a signal is produced based on a detectable change in impedance and processed to activate a venous line clamp such that blood loss due to dislodgment of the access device can be minimized.

61. The method of claim 60 wherein the signal is processed to shut-off a blood pump during dialysis therapy.

62. The method of claim 60 wherein the signal is processed to activate an alarm which signals the detection of blood loss due to dislodgment of the access device.

63. The method of claim 59 wherein the dialysis therapy is selected from the group consisting of hemodialysis, hemodiafiltration, hemofiltration and continuous renal replacement therapy.

64. A method for providing dialysis therapy to a patient in a non-medical facility comprising the steps of:

connecting a patient to a dialysis device via a blood circuit in order to administer dialysis therapy wherein the blood circuit has a pair of electrodes in fluid contact with blood as it flows through the blood circuit;

passing an electrical signal through the blood via the pair of electrodes thereby defining a loop along which an electrical value can be measured;

detecting a disconnection between the patient and the blood circuit in response to a measurable change in the electrical value; and

activating an alarm that alerts the patient to blood loss due to the disconnection thereby allowing the patient to ensure that dialysis therapy is terminated.

65. The method of claim 64 wherein the dialysis therapy is selected from the group consisting of hemodialysis, hemofiltration, hemodiafiltration and continuous renal replacement therapy.

66. The method of claim 64 wherein the dialysis therapy is capable of being administered while the patient is sleeping such that the alarm can awake the patient subsequently allowing the patient to ensure that dialysis therapy is terminated without a third party intervention.

67. A method for providing dialysis therapy in a non-medical setting that does not require a medical care provider to administer the dialysis therapy comprising the steps of:

connecting a patient to a dialysis device via a blood circuit having a pair of electrodes in fluid contact with blood as it flows through the blood circuit;

passing an electrical signal through the blood via the pair of electrodes thereby defining a loop along which an electrical value can be measured;

detecting a disconnection between the patient and the blood circuit in response to a change in the electrical value;

activating an alarm upon the detection of the blood loss; and

terminating the dialysis therapy in response to the activation of the alarm.

68. The method of claim 67 wherein the non-medical setting is a home.

69. The method of claim 67 wherein the dialysis device is coupled to the patient by the patient.

70. The method of claim 67 wherein the dialysis device is coupled to the patient by a third party.

71. The method of claim 67 wherein the dialysis therapy is automatically terminated in response to the alarm.

72. The method of claim 67 wherein the blood loss is due to needle dislodgment of a needle inserted within the patient to administer the dialysis therapy.

73. The method of claim 67 wherein the dialysis therapy is selected from the group consisting of hemodialysis, hemofiltration, hemodiafiltration and continuous renal replacement.