Extracorporeal blood processing methods and apparatus

• US 7,169,352 B1
• Filed: 10/08/2003
• Issued: 01/30/2007
• Est. Priority Date: 12/22/1999
• Status: Expired due to Term

• Current Assignee: Terumo BCT, Inc. (Terumo Corporation)
• Original Assignee: Gambro, Inc. (DaVita Incorporated)
• Inventors: Bainbridge, Marlene Adele, Felt, Thomas J.
• Primary Examiner(s): Zalukaeva; Tatyana
• Assistant Examiner(s): Deak; Leslie R.
• Application Number:
  US10/681,035
• Time in Patent Office: 1,210 Days
• Field of Search: 604/4.01, 604/5.01, 604/6.01, 604/6.03, 604/6.11, 604/6.05, 604/151, 604 65- 67, 210/600, 210/634, 210/645, 210/739, 210/741, 210/781, 210/782, 700/202
• US Class Current: 422/44
• CPC Class Codes: A61M 1/0209 Multiple bag systems for separating or storing blood components
• 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 1/303 having a reservoir for treated blood to be returned
• CPC Class Codes: A61M 1/308 Volume control, e.g. with open or flexible containers, by counting the number of pump revolutions, weighing
• CPC Class Codes: A61M 1/3496 Plasmapheresis; Leucopheresis; Lymphopheresis A61M1/3472 takes precedence
• CPC Class Codes: A61M 1/36 Other treatment of blood in a by-pass of the natural circulatory system, e.g. temperature adaptation, irradiation ; Extra-corporeal blood circuits
• CPC Class Codes: A61M 1/36222 Details related to the interface between cassette and machine
• CPC Class Codes: A61M 1/36224 with sensing means or components thereof
• CPC Class Codes: A61M 1/36225 with blood pumping means or components thereof
• CPC Class Codes: A61M 1/36226 Constructional details of cassettes, e.g. specific details on material or shape
• CPC Class Codes: A61M 1/362262 Details of incorporated reservoirs
• CPC Class Codes: A61M 1/362263 Details of incorporated filters
• CPC Class Codes: A61M 1/362265 Details of valves
• CPC Class Codes: A61M 1/362266 Means for adding solutions or substances to the blood
• CPC Class Codes: A61M 1/3639 Blood pressure control, pressure transducers specially adapted therefor
• CPC Class Codes: A61M 1/3641 Pressure isolators
• CPC Class Codes: A61M 1/3656 Monitoring patency or flow at connection sites; Detecting disconnections
• CPC Class Codes: A61M 1/3693 using separation based on different densities of components, e.g. centrifuging
• CPC Class Codes: A61M 1/3696 with means for adding or withdrawing liquid substances during the centrifugation, e.g. continuous centrifugation
• CPC Class Codes: A61M 2205/123 with incorporated reservoirs
• CPC Class Codes: A61M 2205/17 : with redundant control systems
• CPC Class Codes: A61M 2205/18 : with alarm
• CPC Class Codes: A61M 2205/3331 : Pressure; Flow
• 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 37/00 : Other apparatus for introducing media into the body for reproduction or fertilisation A61B17/425; apparatus for iontophoresis or cataphoresis A61N1/30; Percutany, i.e. introducing medicines into the body by diffusion through the skin salt baths A61H33/04

Abstract

This invention provides a method for controlling a fluid separation system, preferably a blood apheresis system having a leukocyte reduction chamber. The method utilizes a three-level alarm system. A first-level alarm condition is triggered in response to a pressure drop in the system to less than or equal to a specified system pressure and pauses fluid flow in at least a portion of the system. A second-level alarm condition is triggered in response to a specified number of said pressure drops within a specified period and reduces the flow rate of the fluid in the system. The alarm conditions may also trigger a visible and/or audible alarm. These alarm levels permit flow through the leukocyte reduction chamber to continue when the pressure drop is caused by a non-serious, self-resolving or easily-correctable condition such as misalignment of system components.

Claims

1. A fluid separation control system comprising:

pumps for moving fluid through said system;

a fluid pressure monitoring device for sensing fluid pressures in said system and generating pressure signals in response to said sensed pressures;

a processor for receiving said pressure signals and generating alarm-triggering signals in response thereto;

an audible and/or visible alarm triggered by said alarm-triggering signals; and

a flow controller triggered by said alarm-triggering signals;

wherein said processor is programmed to compare said sensed pressures with system pressures and generate a first-level alarm-triggering signal when said sensed pressures are less than or equal to a first-level alarm-triggering sensor pressure;

wherein said first-level alarm-triggering signal causes said flow controller to pause fluid flow in some of said pumps for a specified delay time;

wherein said processor is programmed to count the number of first-level alarm-triggering signals generated within a specified period and generate a second-level alarm-triggering signal when a specified number of such first-level alarm-triggering signals have been generated within said specified period; and

wherein said second-level alarm-triggering signal causes said flow controller to slow down fluid flow rate in said system.

2. The control system of claim 1 wherein said alarm responds to said first-level alarm-triggering signal by sounding an audible alarm and/or displaying a visible alarm.

3. The control system of claim 1 wherein said alarm responds to said second-level alarm-triggering signal by continuously sounding an audible alarm and/or continuously displaying a visible alarm.

4. The fluid separation control system of claim 1 wherein said processor is programmed to calculate said first-level alarm-triggering sensor pressure using a specified system pressure and selected system parameters.

5. The fluid separation control system of claim 4 designed to control a blood apheresis system, wherein said system parameters comprise the hematocrit in the tubing line, the flow rate in the inlet line, the flow rate in the needle, and the hematocrit in the needle.

6. The control system of claim 5 wherein said blood apheresis system comprises a leukocyte reduction chamber.

7. The control system of claim 6 wherein said flow controller does not pause fluid flow through said leukocyte reduction chamber in response to said first-level alarm-triggering signal.

8. The fluid separation control system of claim 5 wherein said processor is programmed to calculate said calculated first-level alarm-triggering pressure using the following formula:

P_{1st level alarm}=Config+75−

0.3309*Q_in/(1−

H_in)−

0.3026*Q_n/(1−

H_n);

wherein P_{1st level alarm} is the first level alarm-triggering sensor pressure;

Config is a configuration specified system pressure (mmHg), Q_in is the flow rate in the inlet tubing line (ml/min.);

H_in is the Hematocrit in the inlet tubing line;

Q_n is the flow rate in the needle (ml/min.); and

H_n is the Hematocrit in the needle.

9. The fluid separation control system of claim 4 wherein said specified system pressure is between about −

100 and −

250 mmHg.

10. The control system of claim 1 wherein said processor is programmed to compare said sensed pressures with a selected first-level alarm-disabling pressure.

11. The control system of claim 10 wherein said processor is programmed to generate a first-level alarm-disabling signal if the sensed pressure rises to a value greater than or equal to a specified first-level alarm-disabling sensor pressure within the specified delay time;

and

wherein the flow controller responds to said first-level alarm-disabling signal by causing pumps which were paused to resume pumping.

12. The control system of claim 11 wherein said processor is programmed to generate a third-level alarm-triggering signal if the sensed pressure does not rise to a value greater than or equal than the specified first-level alarm-disabling sensor pressure within the specified delay time;

and

wherein the flow controller responds to said third-level alarm-triggering signal by shutting down all pumps in the system.

13. The control system of claim 12 wherein said alarm responds to said third-level alarm-triggering signal by sounding an audible alarm and/or displaying a visible alarm.

14. The control system of claim 11 wherein said alarm responds to said first-level alarm-disabling signal by stopping sounding and/or displaying the alarm.

15. The control system of claim 10 wherein said processor is programmed to calculate said first-level alarm-disabling pressure using a specified alarm-disabling system pressure and selected system parameters.

16. The control system of claim 15 wherein said specified alarm-disabling system pressure is between about 0 and about −

150 mmHg.

17. The control system of claim 15 wherein said specified alarm-disabling system pressure is about −

50 mmHg.

18. The control system of claim 1 wherein said specified number of first-level alarm-triggering signals is between about two and about five.

19. The control system of claim 18 wherein said specified number of first-level alarm-triggering signals is about three.

20. The control system of claim 1 wherein said specified delay time is between about 2 and about 6 seconds.

21. The control system of claim 20 wherein said specified delay time is about 5 seconds.

22. The control system of claim 1 wherein said flow controller slows said flow rate in response to said second-level alarm-triggering signal to a rate low enough to prevent triggering a further first-level alarm condition.

23. The control system of claim 1 wherein said flow controller slows said rate to about one-half normal rate.

24. The control system of claim 1 wherein said flow controller maintains said reduced flow rate until an operator operates said flow controller to return said flow rate to normal or to shut down all of said pumps.

25. The control system of claim 1 wherein said specified period is between about 1 and about 10 minutes.

26. The control system of claim 1 wherein said specified period is about five minutes.

27. The control system of claim 1 also comprising a process monitor for assessing completeness of collection of platelets and plasma;

said processor being in signal communication with said process monitor, and being programmed to trigger a second-level alarm condition only if collection of platelets and plasma is incomplete.

28. A fluid separation control system for a blood apheresis system, said apheresis system having a leukocyte reduction chamber for fluidized-bed separation of blood components, said control system comprising:

pumps for moving fluid through said system including said leukocyte reduction chamber;

a fluid pressure monitoring device for sensing fluid pressures in said system and generating pressure signals in response to said sensed pressures;

a processor for receiving said pressure signals and generating alarm-triggering signals in response thereto;

a flow controller triggered by said alarm-triggering signals;

wherein said processor is programmed to compare said sensed pressures with system pressures and generate a first-level alarm-triggering signal when said sensed pressures are less than or equal to a first-level alarm-triggering sensor pressure;

wherein said first-level alarm-triggering signal causes said flow controller to pause fluid flow in some of said pumps for a specified delay time while maintaining flow in said leukocyte reduction chamber;

wherein said processor is programmed to count the number of first-level alarm-triggering signals generated within a specified period and generate a second-level alarm-triggering signal when a specified number of such first-level alarm-triggering signals have been generated within said specified period; and

wherein said second-level alarm-triggering signal causes said flow controller to slow down fluid flow rate in said system and maintaining flow in said leukocyte reduction chamber.

29. The fluid separation control system of claim 28 wherein said processor is programmed to generate a third-level alarm-triggering signal instead of said second-level alarm-triggering signal if a plasma or platelet collection procedure has been completed.

30. The fluid separation control system of claim 29 wherein said third-level alarm-triggering signal stops all pumps.

31. The fluid separation control system of claim 28 wherein said processor is programmed to generate a third-level alarm-triggering signal if said sensed pressures are less than or equal to a first-level alarm-triggering sensor pressure while said second-level alarm-triggering signal is in effect.

32. The fluid separation control system of claim 31 wherein said third-level alarm-triggering signal stops all pumps.

33. The fluid separation control system of claim 28 wherein said first-level alarm-triggering signal pauses all pumps except a platelet pump which maintains flow through said leukocyte reduction chamber.

34. The fluid separation control system of claim 28 wherein said second-level alarm triggering signal causes flow through an inlet pump and an anticoagulant pump to be reduced by a specified flow-reduction factor, while maintaining flow through said leukocyte reduction chamber.

35. The fluid separation control system of claim 34 wherein said specified flow-reduction factor is low enough to cause sensed pressures to fall below said first-level alarm-triggering sensor pressure but high enough to maintain flow through said leukocyte reduction chamber.

36. The fluid separation control system of claim 35 wherein said specified flow-reduction factor is 0.5.