Access disconnection systems and methods

• US 20060184087A1
• Filed: 01/25/2006
• Published: 08/17/2006
• Est. Priority Date: 04/10/2002
• 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: Wariar, Ramesh, Han, James, Falkvall, Thore, Lamberson, George, Hartranft, Thomas P.
• Granted Patent: US 7,959,594 B2
• Time in Patent Office: Days
• US Class Current: 604/6.110
• CPC Class Codes: A61M 1/16 with membranes
• 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 1/367 Circuit parts not covered by the preceding subgroups of group A61M1/3621
• CPC Class Codes: A61M 2205/18 with alarm
• CPC Class Codes: A61M 2205/3317 Electromagnetic, inductive or dielectric measuring means
• CPC Class Codes: A61M 2205/3324 PH measuring means
• CPC Class Codes: A61M 2205/3334 Measuring or controlling the flow rate
• CPC Class Codes: A61M 2205/50 with microprocessors or computers
• 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: A61M 5/5086 for indicating if defective, used, tampered with or unsterile

Abstract

Apparatuses, devices, systems and methods for detecting access disconnection are provided. In one embodiment, a medical fluid system includes (i) a medical fluid machine and (ii) a device operable with the medical fluid machine, the device configured to provide electrical contact with a medical fluid, the device including (a) a tube used during dialysis therapy through which the medical fluid can flow, and (b) a conductive element configured to self-sealingly pierce the tube, the conductive element having a first portion exposed to the medical fluid and a second portion external to the tube.

Claims

1. A medical fluid system comprising:

a medical fluid machine; and

a device operable with the medical fluid machine, the device configured to provide electrical contact with a medical fluid, the device including

(i) a tube used during dialysis therapy through which the medical fluid can flow, and

(ii) a conductive element configured to self-sealingly pierce the tube, the conductive element having a first portion exposed to the medical fluid and a second portion external to the tube.

2. The medical fluid system of claim 1, wherein the conductive element can be used to detect a disconnection between a patient and the tube portion in response to a measurable change in an electrical value associated with an electrical signal passing through the medical fluid.

3. The medical fluid system of claim 1, wherein the first portion includes a cylindrically-shaped conductive member.

4. The medical fluid system of claim 3, which includes a housing having an annular portion through which the cylindrically-shaped conductive member can be secured to the tube.

6. The medical fluid system of claim 1, which includes a clamp mechanism configured to be secured to an outer surface of the tube.

7. The medical fluid system of claim 6, wherein the first portion includes a conductive member attached to the clamp mechanism and is configured to pierce the tube enabling fluid contact between the conductive member and the medical fluid.

8. The medical fluid system of claim 1, wherein the medical fluid machine is of a type selected from the group consisting of:

hemodialysis, hemofiltration, hemodiafiltration, continuous renal replacement therapy and peritoneal dialysis.

9. A medical fluid system comprising:

a medical fluid machine; and

a device configured to provide electrical contact with a medical fluid in a fluid conduit, the device including

(i) a first member including an annular portion capable of accommodating a conductive member in fluid contact with the medical fluid and a first stem portion connected to the annular member, wherein the stem portion has an opening extending therethrough to the annular portion;

(ii) a second member including a base portion with a groove region and a second stem portion with an opening extending therethrough to the groove region, allowing the first member to be inserted and secured to the second member, and

(iii) a contact member configured with the first and second stem portions to enable the contact member to abut against at least a portion of the conductive member, enabling an electrical connection to be made between the conductive member and the contact member.

10. The medical fluid system of claim 9, wherein the first and second members are attached in frictional engagement.

11. The medical fluid system of claim 9, wherein the first and second members are threadinlgy engaged.

12. The medical fluid system of claim 9, further comprising a spring mechanism biased so that the contact member abuts against the electrical contact.

13. The medical fluid system of claim 9, which is configured to use the conductive member to detect a disconnection between a patient and the blood tubing in response to a change in an electrical value associated with an electrical signal passing through the medical fluid.

14. The medical fluid system claim 9, further comprising a retainer member configured to secure the contact member within the second stem portion.

15. The medical fluid system claim 9, wherein the medical fluid machine is of a type selected from the group consisting of:

hemodialysis, hemofiltration, hemodiafiltration, continuous renal replacement therapy and peritoneal dialysis.

16. An extracorporeal blood system comprising:

an extracorporeal blood machine; and

a blood tubing set used during dialysis therapy to connect a patient to the extracorporeal blood machine, the blood tubing set including

(i) first and second blood lines configured to connect the patient to the extracorporeal blood machine via an access device inserted within the patient, enabling blood to flow between the patient and the extracorporeal blood machine with an electrical signal passing therein, and

(ii) a pair of electrical contacts configured to pierce the first and second blood lines to establish a fluid connection with the blood, enabling detection of dislodgment of the access device during the medical therapy.

17. The extracorporeal blood system of claim 16, wherein the first blood line comprises an arterial blood line and the second blood line comprises a venous blood line.

18. The extracorporeal blood system of claim 16, wherein the access device is of a type selected from the group consisting of:

a needle, a catheter, a venous needle and an arterial needle.

19. The extracorporeal blood system of claim 16, wherein the electrical contact pair is connected to a controller enabling detection of dislodgment using a direct-contact measurement.

20. The extracorporeal blood system of claim 16, wherein the medical fluid machine is of a type selected from the group consisting of:

hemodialysis, hemofiltration, hemodiafiltration and continuous renal replacement therapy.

21. An extracorporeal blood system comprising:

an extracorporeal blood machine; and

a blood tubing set used during dialysis therapy to connect a patient to the extracorporeal blood machine, the blood tubing set including

(i) an access device,

(ii) first and second blood lines configured to place the access device in fluid communication with the extracorporeal blood machine, enabling blood to flow between the patient and the extracorporeal blood machine with an electrical signal passing therein,

(iii) a pair of electrical contacts configured to pierce the first and second blood lines to establish a fluid connection with the blood, and

(iv) an electrical contact coupling device attaching at least one of the electrical contacts to the first and second blood lines, enabling detection of dislodgment of the access device during dialysis therapy.

22. The extracorporeal blood system of claim 21, wherein the first blood line comprises a venous blood line and the second blood line comprises an arterial blood line.

23. The extracorporeal blood system of claim 21, wherein the electrical contacts are configured to be coupled to a controller enabling dislodgment detection using a direct-contact measurement.

24. The extracorporeal blood system of claim 21, wherein the medical fluid machine is of a type selected from the group consisting of:

hemodialysis, hemofiltration, hemodiafiltration and continuous renal replacement therapy.

25. An extracorporeal blood system comprising:

an extracorporeal blood machine including an extracorporeal blood circuit;

an access device enabling the extracorporeal blood circuit to be connected to a patient;

a pair of contacts configured to contact blood as the blood flows through the extracorporeal blood circuit; and

a controller configured to model a total impedance Z according to at least two lumped impedances including (i) a lumped impedance Z_D due to components of the extracorporeal blood machine and (ii) a lumped impedance Z_P due to access of the extracorporeal blood circuit to the patient.

26. The extracorporeal blood system of claim 25, wherein Z_P is due at least to the access device and tubing associated with the extracorporeal blood circuit.

27. The extracorporeal blood system of claim 25, wherein Z_D is due at least to a pump, dialyzer and drip chambers.

28. The extracorporeal blood system of claim 25, wherein the controller is configured to assume Z_P approaches infinity upon dislodgment of the access device from the patient, such that Z becomes at least substantially equal to Z_D.

29. The extracorporeal blood system of claim 25, wherein an induction coil is coupled to the extracorporeal blood circuit.

30. The extracorporeal blood system of claim 29, which includes an inductive coupling including a first member and a second member movably attached to the first member allowing for displacement of the first member and the second member into an open arrangement and a closed arrangement, wherein the induction coil is placed around at least a portion of at least one of the first and second members.

31. The extracorporeal blood system of claim 30, wherein the inductive coupling includes a hinge attached to the first member and the second member at the end.

32. The extracorporeal blood system of claim 29, wherein at least a portion of each of the first and second members is made of a material that having a magnetic permeability in an amount effective to converge an electromagnetic field into the induction coil.

33. The extracorporeal blood system of claim 25, wherein the extracorporeal blood machine is of a type selected from the group consisting of:

hemodialysis, hemofiltration, hemodiafiltration and continuous renal replacement therapy.