Systems and methods for dialysis access disconnection

• US 8,529,490 B2
• Filed: 06/09/2011
• Issued: 09/10/2013
• 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, Lamberson, George, Hartranft, Thomas P., Falkvall, Thore
• Primary Examiner(s): DEAK, LESLIE R
• Application Number:
  US13/157,010
• Publication Number:
  US 20110237998A1
• Time in Patent Office: 824 Days
• Field of Search: 604/4.01, 604/5.01, 604/6.16, 210/646, 210/746
• US Class Current: 604/6.16
• 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

An access disconnection method for a machine employing a blood circuit, the blood circuit having a machine segment and a patient access segment, the method comprising: injecting an electrical signal into the blood circuit between the machine segment and the patient access segment; attempting to cause the electrical signal to flow through only the patient access segment and to bypass the machine segment; and measuring the signal in the patient access segment and determining that an access disconnection event has occurred upon a threshold change in the measured signal.

Claims

1. An access disconnection method comprising:

measuring a lumped impedance through a machine segment of a blood circuit;

measuring a lumped impedance through a patient access segment of the blood circuit;

combining the lumped machine segment impedance with the lumped patient access impedance to form a total impedance; and

detecting that an access disconnection has occurred when the total impedance approaches the lumped machine segment impedance.

2. The access disconnection method of claim 1, wherein measuring the lumped machine segment impedance includes lumping at least two of:

a venous air removal chamber impedance, a dialyzer impedance, an arterial air removal chamber impedance, and a blood pump impedance.

3. The access disconnection method of claim 1, wherein measuring the lumped patient access impedance includes lumping a venous tube impedance, a patient access impedance and an arterial tube impedance.

4. The access disconnection method of claim 1, which includes injecting an electrical signal between the machine segment and patient access segment of the blood circuit.

5. The access disconnection method of claim 4, wherein the signal is split, allowing the separate lumped machine segment impedance and the lumped patient access impedance to be measured.

6. The access disconnection method of claim 1, wherein combining the lumped impedance is done according to the relationship

total impedance=((1/lumped machine segment impedance)+(1/lumped patient access impedance))⁻

1.

7. The access disconnection method of claim 1, which includes at least one of:

(i) filtering or (ii) digitizing the lumped machine segment impedance and/or the lumped patient access impedance.