Method to control blood and filtrate flowing through an extracorporeal device

• US 20050004502A1
• Filed: 07/27/2004
• Published: 01/06/2005
• Est. Priority Date: 02/14/2002
• Status: Active Grant

• Current Assignee: Gambro Lundia AB (Baxter International Inc.)
• Original Assignee: CHF Solutions, Inc.
• Inventors: Gelfand, Mark, O'Mahony, John J., Rychlick, Edward G., Halpert, Andrew
• Granted Patent: US 7,540,851 B2
• Time in Patent Office: Days
• US Class Current: 604/4.10
• CPC Class Codes: A61M 1/3403 Regulation parameters
• 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 1/3659 Cannulae pertaining to extracorporeal circulation
• CPC Class Codes: A61M 2205/13 with means for the detection of operative contact with patient, e.g. lip sensor
• CPC Class Codes: A61M 2205/15 Detection of leaks
• CPC Class Codes: A61M 2205/18 with alarm
• CPC Class Codes: A61M 2205/3334 Measuring or controlling the flow rate
• CPC Class Codes: A61M 2205/705 Testing of filters for leaks blood in dialysate A61M1/1692
• CPC Class Codes: A61M 2230/207 hematocrit
• CPC Class Codes: A61M 2230/30 Blood pressure A61M2230/04 takes precedence

Abstract

A method and apparatus are disclosed for controlling blood flow through an extracorporeal blood circuit having a controller comprising the steps of: withdrawing the blood from a withdrawl blood vessel in a patient into the extracorporeal circuit, treating the blood in the circuit and infusing the treated blood into the patient; detecting an occlusion which at least partially blocks the withdrawl or infusion of the blood; reducing the blood flow rate and the rate of filtration in response to the occlusion, and further prompting the patient to move his arm in an effort to alleviate the occlusion.

Claims

1. A method for controlling blood flow through an extracorporeal blood circuit having a controller comprising:

a. withdrawing the blood from a patient into the extracorporeal circuit, treating the blood in the circuit, and infusing the treated blood into the patient;

b. detecting an occlusion that at least partially blocks the withdrawal or infusion of the blood;

c. in response to the detection of the occlusion, the controller automatically prompts the patient to move to alleviate the occlusion;

d. continuing the withdrawal, treatment and infusion of blood if the occlusion is alleviated after step (c), and

e. ceasing the withdrawal of blood if the occlusion is not alleviated within a predetermined time to cessation period after step (c), wherein steps (a) to (e) are performed automatically.

2. A method for controlling blood flow as in claim 1 further comprises issuing an alarm after a predetermined time to alarm period following the detection of the occlusion, wherein the time to alarm period is shorter than the predetermined time to cessation period.

3. A method for controlling blood flow as in claim 2 wherein the alarm in step (d) is issued at least after 30 seconds has elapsed since the occlusion is detected and the occlusion has not been alleviated.

4. A method for controlling blood flow as in claim 3 wherein the alarm is automatically terminated when the occlusion is alleviated.

5. A method for controlling blood flow as in claim 4 wherein the alarm is terminated after five minutes.

6. A method for controlling blood flow as in claim 1 wherein step (c) further includes reducing a blood flow rate in response to the detection of the occlusion and the prompt of the patient follows the flow rate reduction.

7. A method for controlling blood flow as in claim 1 wherein step (c) includes reducing a flow rate of blood through the circuit and further comprises increasing the flow rate of blood after detecting that the occlusion has been alleviated.

8. A method for controlling blood flow as in claim 1 wherein step (e) includes ceasing blood flow through the circuit.

9. A method for controlling blood flow as in claim 1 wherein step (c) includes indicating to the patient to move a particular arm.

10. A method for controlling blood flow as in claim 1 wherein step (c) includes indicating whether the occlusion is in the withdrawal blood vessel or in an infusion blood vessel.

11. A method for controlling blood flow as in claim 1 wherein in step (c) the prompt to the patient is an audible response.

12. A method for controlling blood flow as in claim 1 wherein in step (c) the prompt to the patient is a synthetic voice prompt generated by the controller.

13. A method for controlling blood flow as in claim 1 wherein in step (c) the prompt to the patient is a visual response.

14. A method for controlling blood flow as in claim 1 wherein in step (c) the prompt to the patient is a text message generated on the screen display.

15. A method for controlling blood flow as in claim 1 wherein in step (c) the prompt to the patient is an icon generated on the screen display.

16. A method for controlling blood flow as in claim 1 further comprising ceasing blood flow through the circuit after the controller issues an alarm.

17. A method for controlling blood flow as in claim 1 wherein the blood circuit includes a blood filter, and further comprises step (e) of reducing a flow of filtrate from the filter in response to a reduction of blood flow through the filter and step (f) of increasing the flow of filtrate after the occlusion is alleviated.

18. A method for controlling blood flow as in claim 1 wherein the blood circuit includes a blood filter and further reducing a flow of filtrate from the filter in response to an increase of the suction pressure applied at a filtrate output of the filter, and increasing the flow of filtrate after the suction pressure applied at a filtrate output decreases.

19. A method for controlling blood flow as in claim 1 wherein the blood circuit includes a blood filter, and further comprises temporarily ceasing a flow of filtrate from the filter in response to a reduction of blood flow through the filter and resuming the flow of filtrate after the occlusion is alleviated.

20. A method for controlling blood flow as in claim 1 wherein step (b) is performed by detecting a withdrawal pressure or infusion pressure crossing a predetermined threshold value.

21. A method for controlling blood flow as in claim 1 wherein step (d) further comprises detecting alleviation of the occlusion by sensing a pressure change in the withdrawal or infusion of the blood.

22. A method for controlling blood flow through an extracorporeal blood ultrafiltration circuit having a controller comprising:

a. selecting a desired filtration rate for the ultrafiltration circuit to extract filtrate for an ultrafiltration treatment;

b. withdrawing the blood from a patient into the extracorporeal circuit, filtering the blood to extract filtrates at the desired filtration rate, and infusing the filtered blood into the patient;

c. detecting a pressure of the blood being withdrawn or infused exceeding a predetermined threshold pressure value;

d. reducing a blood flow rate through the circuit in response to the detection of the pressure exceeding the threshold;

e. in connection with step (d), reducing a rate of filtrate extraction to a rate less than the desired filtration rate;

f. increasing the blood flow rate through the circuit after determining that the pressure of the blood being withdrawn or infused is within the threshold pressure value, and

g. increasing the filtration rate after step (f).

23. A method for controlling blood flow as in claim 22 wherein step (e) includes reducing the rate of filtrate extraction to substantially cease filtration.

24. A method for controlling blood flow as in claim 22 wherein step (e) includes reducing the rate of filtrate extraction proportionally to the reduction of blood flow rate through the circuit.

25. A method for controlling blood flow as in claim 22 further comprised step (h) of prompting the patient to move after step (c) and before step (f).

26. A method for controlling filtration in a blood circuit having withdrawal and infusion blood passages connected to a patient, a filter, a blood pump, and a filtrate pump, said method comprising:

a. withdrawing the blood from a patient into the blood circuit, filtering liquid ultrafiltrate from the blood in the filter, and infusing the filtered blood into the patient;

b. controlling a filtrate flow from the filter to maintain an filtrate flow pressure above a predetermined pressure value;

c. in response to a reduction of blood flow through the blood circuit, automatically reducing the filtrate flow.

27. A method for controlling ultrafiltration in a blood circuit as claim 26 wherein the blood circuit includes a filtrate pump controlling the flow of filtrate from the filter, and step (b) is performed by controlling a speed of the filtrate pump.

28. A method for controlling ultrafiltration in a blood circuit as claim 26 wherein step (c) is performed by automatically and temporarily ceasing the flow of filtrate.

29. A method for controlling ultrafiltration in a blood circuit as claim 26 wherein step (c) is performed by reducing the filtrate flow proportionally to the reduction of blood flow.

30. A method for controlling filtration in a blood circuit as claim 26 further comprising issuing an alarm if the flow rate of filtration remains below a predetermined ultrafiltration flow rate for a prolonged period.

31. A method for controlling filtration in a blood circuit as claim 30 where the prolonged period is at least 5 minutes.

32. A method for controlling filtration in a blood circuit as claim 26 further comprising issuing an alarm if the amount of ultrafiltrate obtained in a predetermined period is less than a predetermined amount.

33. A method for controlling filtration in a blood circuit as claim 32 wherein the predetermined period is 30 minutes.