METHOD AND DEVICE FOR MONITORING AN EXTRACORPOREAL BLOOD CIRCUIT

• US 20090292236A1
• Filed: 07/11/2007
• Published: 11/26/2009
• Est. Priority Date: 07/14/2006
• Status: Active Grant

• Current Assignee: Fresenius Medical Care Deutschland GmbH (Fresenius Medical Care AG)
• Original Assignee: Fresenius Medical Care Deutschland GmbH (Fresenius Medical Care AG)
• Inventors: Kleinekofort, Wolfgang
• Granted Patent: US 9,878,086 B2
• Time in Patent Office: Days
• US Class Current: 604/6.16
• CPC Class Codes: A61M 1/3639 Blood pressure control, pressure transducers specially adapted therefor
• 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 1/3661 for haemodialysis

Abstract

To monitor an extracorporeal blood circuit during extracorporeal blood treatment, the arterial pressure and venous pressure in the arterial branch and venous branch of the extracorporeal circuit are measured by pressure sensors, and the sum P_s and the difference ΔP of the arterial pressure and/or venous pressure measured at the same time are calculated. A possible error state is indicated when the sum P_s and/or difference ΔP lie outside predetermined limit value windows A and B. To reduce the susceptibility to error, a check is preferably also made to ascertain whether the two above conditions are satisfied for n successive measurements.

Claims

1-12. -12. (canceled)

13. A method for monitoring an extracorporeal blood circuit during extracorporeal blood treatment, in which blood flows from an arterial vascular access, through an arterial branch of an extracorporeal blood circuit, into a blood treatment device, through a venous branch of the extracorporeal circuit, and to a venous vascular access, comprising:

(a) at time t_n, measuring an arterial pressure (P_art) in the arterial branch of the extracorporeal circuit;

(b) at time t_n, measuring a venous pressure (P_ven) in the venous branch of the extracorporeal circuit;

(c) calculating at least one of a sum (P_S) of the arterial pressure and the venous pressure measured at time t_n and a difference (Δ

P) of the arterial pressure and the venous pressure measured at time t_n; and

(d) comparing the at least one of P_S at time t_n to a predetermined limit value window A, and Δ

P at time t_n to a predetermined limit value window B.

14. The method of claim 13, wherein step (c), comprises calculating both P_S and Δ

P.

15. The method of claim 13, wherein step (c), consists of calculating P_S.

16. The method of claim 13, wherein step (c) consists of calculating Δ

P.

17. The method of claim 14, wherein a first alarm condition is present if both the following conditions are satisfied:

the sum P_S lies outside the predetermined limit value window A, and the difference Δ

P lies outside the predetermined limit value window B.

18. The method of claim 13, wherein a false alarm is present if only one of the following conditions is satisfied:

the sum P_S lies outside the predetermined limit value window A, or the difference Δ

P lies outside the predetermined limit value window B.

19. The method of claim 14, further comprising:

repeating the steps (a) through (d) a predetermined number of times (n).

20. The method of claim 19, wherein if the first alarm condition is present for n consecutive times, an error state is detected.

21. The method of claim 20, wherein if the error state is detected, then an alarm is triggered.

22. The method of claim 20, wherein if the error state is detected, then blood flow in the extracorporeal circuit is interrupted.

23. A device for detecting an error state in extracorporeal blood treatment comprising:

an extracorporeal blood circuit comprising an arterial blood conduit connected to an inlet of a blood treatment device and to an arterial attachment for a vascular access, and a venous blood conduit connected to an outlet of the blood treatment device and to a venous attachment for the vascular access;

an arterial pressure sensor for measuring the pressure in the arterial blood conduit;

a venous pressure sensor for measuring the pressure in the venous blood conduit;

a computing unit adapted to calculate at least one of a sum (P_S) of the values of arterial pressure and venous pressure measured at time t_n, and a difference (Δ

P) of the values of the arterial pressure and venous pressure measured at time t_n;

an evaluation unit cooperating with the computing unit during the blood treatment to continuously compare the at least one of P_S and Δ

P to respective predetermined limit values.

24. The device of claim 23, wherein the computing unit is adapted to calculate both P_S and Δ

P.

25. The device of claim 23, wherein the computing unit is adapted to calculate only P_S.

26. The device of claim 23, wherein the computing unit is adapted to calculate only Δ

P.

27. The device of claim 24, wherein a first alarm condition is present if both P_S and Δ

P lie outside the respective predetermined limit values.

28. The device of claim 23, wherein the respective predetermined limit values form predetermined limit value window A and predetermined limit value window B, each having a predetermined upper limit value and a predetermined lower limit value;

and

the evaluation unit comprises a means for comparing P_S to the upper limit value and the lower limit value of the predetermined limit value window A, and a means for comparing Δ

P to the upper limit value and the lower limit value of the predetermined limit value window B.

29. The device of claim 27, wherein the evaluation unit cooperates with the computing unit to evaluate P_S and Δ

P at a predetermined number of consecutive times (n), and an error state is detected the first alarm condition is present for n consecutive times.

30. The device of claim 29, further comprising an alarm unit that emits an alarm if the error state is detected.

31. The device of claim 29, further comprising a means for interrupting the blood flow in the extracorporeal circuit if the error state is detected.