Extracorporeal blood processing methods with multiple alarm levels

• US 8,088,090 B2
• Filed: 09/08/2006
• Issued: 01/03/2012
• Est. Priority Date: 12/22/1999
• Status: Active Grant

• Current Assignee: Terumo BCT, Inc. (Terumo Corporation)
• Original Assignee: Caridianbct Biotechnologies LLC (Baxter International Inc.)
• Inventors: Felt, Thomas J., Bainbridge, Marlene Adele
• Primary Examiner(s): DEAK, LESLIE R
• Application Number:
  US11/530,131
• Publication Number:
  US 20070093774A1
• Time in Patent Office: 1,943 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: 604/6.01
• 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 at least a two-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 method for controlling a fluid separation system comprising:

triggering a first-level alarm condition in response to a pressure drop to less than or equal to a specified system pressure, said first alarm condition comprising pausing fluid flow in at least a portion of said system for a specified delay time;

triggering a second alarm condition in response to a specified number of said pressure drops within a specified period, said second alarm condition comprising reducing flow rate of fluid in said system.

2. The method of claim 1 wherein said specified number of specified pressure drops is between about two and about five.

3. The method of claim 1 wherein said specified delay time is between about 2 and about 6 seconds.

4. The method of claim 3 wherein said specified delay time is about 5 seconds.

5. The method of claim 1 wherein said specified system pressure in said system is between about −

100 and about −

250 mmHg.

6. The method of claim 1 wherein said first-level alarm condition comprises sounding an audible alarm and/or displaying a visible alarm.

7. The method of claim 1 wherein said second-level alarm condition comprises sounding an audible alarm and/or displaying a visible alarm.

8. The method of claim 7 wherein said alarm is sounded and/or displayed continuously.

9. The method of claim 1 also comprising returning said flow rate in said system to normal flow rate if pressure in the system rises to a specified first-level alarm-disabling pressure.

10. The method of claim 9 wherein said selected first-level alarm-disabling pressure in the system is between about 0 and about −

150 mmHg.

11. The method of claim 10 wherein said specified first-level alarm-disabling pressure in the system is about −

50 mmHg.

12. The method of claim 1 also comprising:

triggering a third alarm condition in response to failure of pressure in the system to rise to a specified first-level alarm-disabling pressure in the system.

13. The method of claim 1 wherein said fluid separation system is a blood apheresis system.

14. The method of claim 13 wherein said blood apheresis system comprises a leukocyte reduction chamber.

15. The method of claim 14 wherein during said first-level alarm condition, flow through said leukocyte reduction chamber is maintained.

16. The method of claim 1 wherein during said second-level alarm condition, said flow rate is low enough to prevent triggering a further first-level alarm condition.

17. The method of claim 16 wherein during said second-level alarm condition, flow in said system is reduced to about one-half normal rate.

18. The method of claim 1 wherein said specified period is between about 1 and about 10 minutes.

19. The method of claim 1 wherein said specified period is about five minutes.

20. The method of claim 1 wherein said reduced flow rate persists for an indefinite period.

21. The method of claim 20 wherein said second-level alarm condition is terminated by an operator by resolving the problem which gave rise to said second-level alarm condition and returning said flow rate to normal.

22. The method of claim 21 wherein said second-level alarm condition is terminated by an operator by shutting down the system.

23. The method of claim 1 wherein said specified system pressure is used to calculate a specified sensor pressure which triggers said first-level alarm by modifying the specified system pressure using selected system parameters.

24. The method of claim 23 wherein said system is a blood apheresis system, and said selected system parameters include the hematocrit in the inlet tubing line, the flow rate in the inlet tubing line, the flow rate in the needle, and the hematocrit in the needle.

25. The method of claim 24 wherein said specified sensor pressure is determined by the following formula:

Specified Sensor Pressure=Config−

50−

0.3309*Q_IN/(1−

H_IN)−

0.3026*Q_N/(1−

H_N)

wherein 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.