Extracorporeal Blood Processing Apparatus And Methods With Pressure Sensing

• US 20070232980A1
• Filed: 06/11/2007
• Published: 10/04/2007
• Est. Priority Date: 12/22/1999
• Status: Active Grant

• Current Assignee: Terumo BCT, Inc. (Terumo Corporation)
• Original Assignee: Gambro BCT, Inc. (Terumo Corporation)
• Inventors: FELT, Thomas, BAINBRIDGE, Marlene
• Granted Patent: US 7,780,618 B2
• Time in Patent Office: Days
• US Class Current: 604/6.100
• 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 an apparatus and method for controlling a fluid separation system, preferably a blood apheresis system, by sensing fluid pressure and comparing the sensed fluid pressure to a threshold value.

Claims

1. A method for controlling an extracorporeal blood processing system, comprising an extracorporeal blood circuit, in response to fluid pressure changes in a fluid flow in the extracorporeal blood circuit, the method comprising the steps of:

sensing a fluid pressure in the extracorporeal blood circuit;

comparing the fluid pressure to a threshold value;

stopping fluid flow, when the fluid pressure is below the threshold value; and

resuming fluid flow, when the fluid pressure rises to a set point within a selected period of time.

2. A method according to claim 1, wherein the set point is the threshold value.

3. A method according to claim 1, further comprising the step of setting a full alarm condition when the fluid pressure being sensed does not rise above the set point within a selected period of time.

4. A method according to claim 3, in which the step of setting a full alarm condition comprises complete stoppage of fluid flow in the extracorporeal blood circuit.

5. A method according to claim 1, further comprising the step of emitting a warning alarm signal contemporaneously with said step of stopping fluid flow.

6. A method according to claim 5, in which said warning alarm signal is an audible squeeze beep sound.

7. A method according to claim 1, further comprising the steps of:

interpreting a particular quantity of fluid pressure comparisons where the fluid pressure is below the threshold value occurring within a particular time period; and

signaling an alarm.

8. A method according to claim 7, in which the particular quantity of fluid pressure comparisons is set to be three and the particular time period is set to be three minutes.

9. A method according to claim 1, in which the threshold value is adjustable in view of certain pre-selected parameters including fluid flow rate and fluid viscosity.

10. A method according to claim 9, wherein the extracorporeal blood circuit has an inlet tubing for fluid flow, and a needle for fluid flow into the inlet tubing, and the threshold value is:

Draw Threshold Value=Config+75−

0.3309*Q_in/(1−

H_in)−

0.3026*Q_n/(1−

H_n)

where,

Config=a configuration pre-selected pressure value

Q_in=fluid flow rate in the inlet tubing line;

H_in=Hematocrit in the inlet tubing line;

Q_n=fluid flow rate in the needle; and

H_n=Hematocrit in the needle.

11. A method according to claim 9, wherein the extracorporeal blood circuit has an inlet tubing for fluid flow, and a needle for fluid flow into the inlet tubing;

and the threshold value is;

Draw Threshold Value=Config+75−

0.3309*Q_in/(1−

H_in)−

0.5602*Q_n/(1−

H_n)

where,

Config=a configuration pre-selected pressure value

Q_in=fluid flow rate in the inlet tubing line;

H_in=Hematocrit in the inlet tubing line;

Q_n=fluid flow rate in the needle; and

H_n=Hematocrit in the needle.

12. A method according to claim 1, wherein the extracorporeal blood circuit has a return tubing for fluid flow, and the method further comprises:

sensing return fluid pressure; and

comparing the return fluid pressure to the return threshold value that is adjustable in view of certain pre-selected parameters including fluid flow rate and fluid viscosity.

13. A method according to claim 12, wherein the extracorporeal blood circuit has a needle for fluid flow from the return tubing, and the return threshold value is:

Return Threshold Value=Config−

50−

0.3309*Q_in/(1−

H_in)−

0.3026*Q_n/(1−

H_n)

where,

Config=a configuration pre-selected pressure value

Q_in=fluid flow rate in the return tubing line;

H_in=Hematocrit in the return tubing line;

Q_n=fluid flow rate in the needle; and

H_n=Hematocrit in the needle.

14. A method according to claim 12, wherein the extracorporeal blood circuit has a needle for fluid flow from the return tubing, and the return threshold value is:

Return Threshold Value=Config−

50−

0.3309*Q_in/(1−

H_in)−

0.5602*Q_n/(1−

H_n)

where,

Config=a configuration pre-selected pressure value

Q_in=fluid flow rate in the return tubing line;

H_in=Hematocrit in the return tubing line;

Q_n=fluid flow rate in the needle; and

H_n=Hematocrit in the needle.

15. A method according to claim 1, wherein the extracorporeal blood processing system is a single needle blood separation system in which blood is drawn from a donor/patient, separated blood components are first accumulated in a reservoir, and the accumulated components are then cyclically pumped out of the reservoir back to the donor/patient, the method comprising the step of pumping the accumulated fluid components out of the reservoir simultaneously with stopping fluid flow.

16. A method according to claim 15, in which the blood is alternately drawn and returned in a cycle, and in which the step of pumping the accumulated fluid components out of the reservoir is conditioned upon the draw cycle being greater than a pre-selected percentage of completion.

17. A method according to claim 16, in which the percentage of completion is set at 90%.

18. A method according claim 1, in which the e set point is −

50 mmHg.

19. An extracorporeal blood processing apparatus adapted to cooperate with an extracorporeal blood circuit, comprising:

a fluid pressure-monitoring device for sensing a pressure in an extracorporeal blood circuit;

at least one fluid flow control device for circulating at least one liquid in the extracorporeal blood circuit; and

a control device for receiving a pressure signal from the pressure monitoring device and comparing it to a threshold value, and for causing the operation of the at least one flow control device,

wherein the control device is programmed for;

stopping the at least one fluid flow control device, when the fluid pressure sensed by the fluid pressure monitoring device is below the threshold value; and

resuming the operation of the at least one flow control device, when the fluid pressure sensed by the fluid pressure monitoring device rises above a set point within a selected period of time.

20. An apparatus according to claim 19, wherein the set point is the threshold value.

21. An apparatus according to claim 19, wherein the control device is further programmed for setting a full alarm condition when the fluid pressure sensed by the fluid pressure monitoring device does not rise above the set point within a selected period of time.

22. An apparatus according to claim 21, in which the control device is programmed for stopping the operation of the at least one flow control device when setting a full alarm condition.

23. An apparatus according to claim 19, wherein the control device is further programmed for causing a warning alarm signal to be emitted when pausing the at least one fluid flow control device.

24. An apparatus according to claim 19, wherein the control device is further programmed for:

interpreting a particular quantity of fluid pressure comparisons where the fluid pressure is below the threshold value occurring within a particular time period; and

signaling an alarm.

25. An apparatus according to claim 24, in which the particular quantity of fluid pressure comparisons is set to be three and the particular time periods set to be three minutes.

26. An apparatus according to claim 19, in which the threshold value is adjustable in view of certain pre-selected parameters including fluid flow rate and fluid viscosity.

27. An apparatus according to claim 26, adapted for cooperating with an extracorporeal blood circuit having an inlet tubing for fluid flow, and a needle for fluid flow into the inlet tubing, and the threshold value is:

Draw Threshold Value=Config+75−

0.3309*Q_in/(1−

H_in)−

0.3026*Q_n/(1−

H_n)

where,

Config=a configuration pre-selected pressure value

Q_in=fluid flow rate in the inlet tubing line;

H_in=Hematocrit in the inlet tubing line;

Q_n=fluid flow rate in the needle; and

H_n=Hematocrit in the needle.

28. An apparatus according to claim 26, adapted for cooperating with an extracorporeal blood circuit having an inlet tubing for fluid flow, and a needle for fluid flow into the inlet tubing, and the threshold value is:

Draw Threshold Value=Config+75−

0.3309*Q_in/(1−

H_in)−

0.5602*Q_n/(1−

H_n)

where,

Config=a configuration pre-selected pressure value

Q_in=fluid flow rate in the inlet tubing line;

H_in=Hematocrit in the inlet tubing line;

Q_n=fluid flow rate in the needle; and

H_n=Hematocrit in the needle.

29. An apparatus according to claim 19, adapted for cooperating with an extracorporeal blood circuit having a return tubing for fluid flow, wherein the fluid pressure monitoring device is adapted for sensing a return fluid pressure and the control device is programmed for comparing the return fluid pressure to a return threshold value that is adjustable in view of certain pre-selected parameters including fluid flow rate and fluid viscosity.

30. An apparatus according to claim 29, wherein the return threshold value is:

Return Threshold Value=Config−

50−

0.3309*Q_in/(1−

H_in)−

0.3026*Q_n/(1−

H_n)

where,

Config=a configuration pre-selected pressure value

Q_in=fluid flow rate in the return tubing line;

H_in=Hematocrit in the return tubing line;

Q_n=fluid flow rate in the needle; and

H_n=Hematocrit in the needle.

31. An apparatus according to claim 29, wherein the return threshold value is:

Return Threshold Value=Config−

50−

0.3309*Q_in/(1−

H_in)−

0.5602*Q_n/(1−

H_n)

where,

Config=a configuration pre-selected pressure value

Q_in=fluid flow rate in the return tubing line;

H_in=Hematocrit in the return tubing line;

Q_n=fluid flow rate in the needle; and

H_n=Hematocrit in the needle.

32. The apparatus according to claim 19, for cooperating with an extracorporeal blood circuit having a reservoir for storing separated blood components to be cyclically pumped out of the reservoir back to a donor/patient, wherein:

the at least one fluid flow control device comprises a blood inlet pump and a blood return pump; and

the control device is further programmed for simultaneously causing the blood return pump to pump the accumulated fluid components out of the reservoir and the blood inlet pump to pause, when the fluid pressure sensed by the fluid pressure monitoring device is below the threshold value.

33. An apparatus according to claim 32, in which the control device is programmed for causing blood to be alternately drawn by the blood inlet pump and returned by the blood return pump in a cycle, and for causing the blood return pump to pump the accumulated fluid components out of the reservoir depending upon the draw cycle being greater than a pre-selected percentage of completion.