Dialysis system having non-invasive fluid velocity sensing

• US 9,724,456 B2
• Filed: 10/08/2014
• Issued: 08/08/2017
• Est. Priority Date: 10/22/2007
• Status: Active Grant

• Current Assignee: Baxter Healthcare SA (Baxter International Inc.), Baxter International Inc.
• Original Assignee: Baxter Healthcare SA (Baxter International Inc.), Baxter International Inc.
• Inventors: Muller, Matthew, Rohde, Justin B., Jablonski, Mark E., Busby, Donald
• Primary Examiner(s): BASS, DIRK R
• Application Number:
  US14/509,323
• Publication Number:
  US 20150021252A1
• Time in Patent Office: 1,035 Days
• CPC Class Codes: A61M 1/1524 the interface providing means for actuating on functional elements of the cassette, e.g. plungers
• CPC Class Codes: A61M 1/154 with sensing means or components thereof
• CPC Class Codes: A61M 1/155 with treatment-fluid pumping means or components thereof
• CPC Class Codes: A61M 1/1565 Details of valves
• CPC Class Codes: A61M 1/16 with membranes
• CPC Class Codes: A61M 1/1607 before use, i.e. upstream of dialyser
• CPC Class Codes: A61M 1/1613 Profiling or modelling of patient or predicted treatment evolution or outcome
• CPC Class Codes: A61M 1/1645 with mechanically linked peristaltic dialysis fluid pumps one upstream, the other one downstream of the dialyser
• CPC Class Codes: A61M 1/1647 with flow rate measurement of the dialysis fluid, upstream and downstream of the dialyser
• CPC Class Codes: A61M 1/1658 Degasification
• CPC Class Codes: A61M 1/288 Priming priming in extracorporeal blood circuits A61M1/3643
• CPC Class Codes: A61M 1/34 Filtering material out of the blood by passing it through a membrane, i.e. hemofiltration or diafiltration
• CPC Class Codes: A61M 1/3403 Regulation parameters
• CPC Class Codes: A61M 1/341 by measuring the filtrate rate or volume
• CPC Class Codes: A61M 1/3413 Diafiltration
• 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 1/362265 Details of valves
• CPC Class Codes: A61M 1/3643 Priming, rinsing before or after use
• CPC Class Codes: A61M 1/3644 Mode of operation
• CPC Class Codes: A61M 1/3649 : using dialysate as priming or rinsing liquid
• CPC Class Codes: A61M 1/365 : through membranes, e.g. by inverted trans-membrane pressure [TMP]
• CPC Class Codes: A61M 1/3656 : Monitoring patency or flow at connection sites; Detecting disconnections
• CPC Class Codes: A61M 2205/12 : with interchangeable cassettes forming partially or totally the fluid circuit
• CPC Class Codes: A61M 2205/18 : with alarm
• CPC Class Codes: A61M 2205/3306 : Optical measuring means
• CPC Class Codes: A61M 2205/3313 : used specific wavelengths
• CPC Class Codes: A61M 2205/3334 : Measuring or controlling the flow rate
• CPC Class Codes: A61M 2205/3368 : Temperature
• CPC Class Codes: A61M 2205/50 : with microprocessors or computers
• CPC Class Codes: A61M 2230/20 : Blood composition characteristics
• CPC Class Codes: G01F 1/708 : Measuring the time taken to traverse a fixed distance

Abstract

A dialysis system includes a dialysis instrument including a blood pump, a dialysate inlet pump, a dialysate outlet pump, and at least one fluid velocity sensor, each sensor including an emitter and a receiver, a dialyzer arranged (i) to receive blood pumped by the blood pump, (ii) to receive fresh dialysate pumped by the dialysate inlet pump and (iii) such that used dialysate is pumped from the dialyzer by the dialysate outlet pump, and a disposable cassette including a to-dialyzer dialysate pathway carrying dialysate pumped by the dialysate inlet pump and a from-dialyzer dialysate pathway carrying used dialysate pumped by the dialysate outlet pump, wherein at least one of the to-dialyzer dialysate pathway or the from-dialyzer dialysate pathway includes at least one sensing area so positioned and arranged such that when the disposable cassette is mounted to the instrument, the sensing area is coupled operably with both the emitter and the receiver of the at least one fluid velocity sensor.

Claims

1. A dialysis system comprising:

a dialysis instrument including

a blood pump,

a dialysate inlet pump,

a dialysate outlet pump, and

at least one fluid velocity sensor, each sensor including an emitter and a receiver;

a dialyzer arranged (i) to receive blood pumped by the blood pump, (ii) to receive fresh dialysate pumped by the dialysate inlet pump and (iii) such that used dialysate is pumped from the dialyzer by the dialysate outlet pump; and

a disposable cassette including a to-dialyzer dialysate pathway carrying dialysate pumped by the dialysate inlet pump and a from-dialyzer dialysate pathway carrying used dialysate pumped by the dialysate outlet pump, wherein at least one of the to-dialyzer dialysate pathway or the from-dialyzer dialysate pathway within the cassette includes a first portion formed at least in part by a flexible sheet and a second portion formed by rigid sidewalls and a rigid outer wall, the second portion defining at least one sensing area so positioned and arranged such that when the disposable cassette is mounted to the instrument, the at least one sensing area is coupled operably with both the emitter and the receiver of the at least one fluid velocity sensor.

2. The dialysis system of claim 1, wherein the at least one fluid velocity sensor is used to monitor a flowrate and an overall volume of dialysate delivered through the at least one of the to-dialyzer dialysate pathway or the from-dialyzer dialysate pathway.

3. The dialysis system of claim 1, wherein the emitter and the receiver of the at least one fluid velocity sensor are located on a same side of the disposable cassette.

4. The dialysis system of claim 1, wherein the emitter and the receiver of the at least one fluid velocity sensor are located on opposite sides of the disposable cassette.

5. The dialysis system of claim 1, wherein the at least one sensing area is aligned operably with both the emitter and the receiver of the at least one fluid velocity sensor.

6. The dialysis system of claim 1, wherein the at least one fluid velocity sensor is an optical, laser or heat pulse sensor.

7. The dialysis system of claim 1, wherein at least one of:

(i) the to-dialyzer dialysate pathway is positioned upstream or downstream of the dialysate inlet pump; and

(ii) the from-dialyzer dialysate pathway is positioned upstream or downstream of the dialysate outlet pump.

21. The dialysis system of claim 1, wherein the flexible sheet covers a side of the cassette including the rigid outer wall.

26. The dialysis system of claim 1, wherein the first portion formed at least in part by the flexible sheet is adjacent to at least one of an inlet or an outlet of the at least one sensing area.

8. A dialysis system comprising:

a dialyzer;

a blood pump in fluid communication with the dialyzer;

a dialysate inlet pump in fluid communication with a dialysate inlet of the dialyzer;

a dialysate outlet pump in fluid communication with a dialysate outlet of the dialyzer;

a first non-invasive fluid velocity sensor positioned to sense an inlet velocity of dialysate pumped to the dialyzer inlet by the dialysate inlet pump;

a second non-invasive fluid velocity sensor positioned to sense an outlet velocity of dialysate pumped from the dialyzer outlet by the dialysate outlet pump; and

a disposable cassette including a to-dialyzer dialysate pathway carrying dialysate pumped by the dialysate inlet pump and a from-dialyzer dialysate pathway carrying used dialysate pumped by the dialysate outlet pump, the to-dialyzer dialysate pathway within the cassette including a first to-dialyzer portion formed at least in part by a flexible sheet and a second to-dialyzer portion formed by rigid sidewalls and a rigid outer wall, the second to-dialyzer portion defining a first sensing area positioned and arranged to couple operably with the first non-invasive fluid velocity sensor, the from-dialyzer dialysate pathway within the cassette including a first from-dialyzer portion formed at least in part by a flexible sheet and a second from-dialyzer portion formed by rigid sidewalls and a rigid outer wall, the second from-dialyzer portion defining a second sensing area positioned and arranged to couple operably with the second non-invasive fluid velocity sensor.

9. The dialysis system of claim 8, wherein at least one of:

(i) the to-dialyzer dialysate pathway is positioned upstream or downstream of the dialysate inlet pump; and

(ii) the from-dialyzer dialysate pathway is positioned upstream or downstream of the dialysate outlet pump.

10. The dialysis system of claim 8, wherein the disposable cassette includes a bypass line positioned to selectively enable the dialysate inlet pump to pump dialysate past both of the non-invasive fluid velocity sensors to calibrate the sensors.

11. The dialysis system of claim 10, which includes a logic implementer programmed to perform (i) a calibration mode in which the bypass line is opened to calibrate the first and second non-invasive fluid velocity sensors and (ii) a therapy mode in which the bypass line is closed.

22. The dialysis system of claim 8, wherein the flexible sheet covers a side of the cassette including the rigid outer wall of at least one of the to-dialyzer dialysate pathway and the from-dialyzer dialysate pathway.

27. The dialysis system of claim 8, wherein at least one of:

(i) the first to-dialyzer portion formed at least in part by the flexible sheet is adjacent to at least one of an inlet or an outlet of the first sensing area;

or (ii) the first from-dialyzer portion formed at least in part by the flexible sheet is adjacent to at least one of an inlet or an outlet of the second sensing area.

12. A dialysis system comprising:

a dialysis instrument including

a blood pump,

a dialysate inlet pump,

a dialysate outlet pump,

a first fluid velocity sensor including a first emitter and a first receiver,

a second fluid velocity sensor including a second emitter and a second receiver;

a dialyzer arranged (i) to receive blood pumped by the blood pump, (ii) to receive fresh dialysate pumped by the dialysate inlet pump and (iii) such that used dialysate is pumped from the dialyzer by the dialysate outlet pump; and

a disposable cassette including a to-dialyzer dialysate pathway carrying dialysate pumped by the dialysate inlet pump and a from-dialyzer dialysate pathway carrying used dialysate pumped by the dialysate outlet pump, the to-dialyzer dialysate pathway within the cassette including a first to-dialyzer portion formed at least in part by a flexible sheet and a second to-dialyzer portion formed by rigid sidewalls and a rigid outer wall, the second to-dialyzer portion defining a first sensing area so positioned and arranged such that when the disposable cassette is mounted to the instrument the first sensing area is coupled operably with both the first emitter and the first receiver of the first fluid velocity sensor, the from-dialyzer dialysate pathway within the cassette including a first from-dialyzer portion formed at least in part by a flexible sheet and a second from-dialyzer portion formed by rigid sidewalls and a rigid outer wall, the second from-dialyzer portion defining a second sensing area so positioned and arranged such that when the disposable cassette is mounted to the instrument the second sensing area is coupled operably with both the second emitter and the second receiver of the second fluid velocity sensor.

13. The dialysis system of claim 12, wherein at least one of:

(i) the first emitter and the first receiver of the first fluid velocity sensor are located on a same side of the disposable cassette;

or (ii) the second emitter and the second receiver of the second fluid velocity sensor are located on a same side of the disposable cassette.

14. The dialysis system of claim 12, wherein at least one of:

(i) the first emitter and the first receiver of the first fluid velocity sensor are located on opposite sides of the disposable cassette;

or (ii) the second emitter and the second receiver of the second fluid velocity sensor are located on opposite sides of the disposable cassette.

15. The dialysis system of claim 12, wherein at least one of the first fluid velocity sensor or the second fluid velocity sensor is non-invasive.

23. The dialysis system of claim 12, wherein the flexible sheet covers a side of the cassette including the rigid outer wall of at least one of the to-dialyzer dialysate pathway and the from-dialyzer dialysate pathway.

28. The dialysis system of claim 12, wherein at least one of:

(i) the first to-dialyzer portion formed at least in part by the flexible sheet is adjacent to at least one of an inlet or an outlet of the first sensing area;

or (ii) the first from-dialyzer portion formed at least in part by the flexible sheet is adjacent to at least one of an inlet or an outlet of the second sensing area.

16. A dialysis system comprising:

a dialyzer;

a blood pump in fluid communication with the dialyzer;

a dialysate inlet pump configured to pump dialysate to the dialyzer;

a dialysate outlet pump configured to pump dialysate from the dialyzer;

a dialysis instrument configured to actuate the dialysate inlet and outlet pumps, the instrument including a first non-invasive fluid velocity sensor and a second non-invasive fluid velocity sensor; and

a disposable cassette operable with the dialysis instrument, the disposable cassette including a to-dialyzer sensing area formed by rigid sidewalls and a rigid outer wall and located upstream or downstream from a first pathway within the disposable cassette formed at least in part by a flexible sheet, the to-dialyzer sensing area further located upstream or downstream from the dialysate inlet pump, the to-dialyzer sensing area operable with the first non-invasive fluid velocity sensor when the disposable cassette is placed in the dialysis instrument, the disposable cassette further including a from-dialyzer sensing area formed by rigid sidewalls and a rigid outer wall and located upstream or downstream from a second pathway within the disposable cassette formed at least in part by a flexible sheet, the from-dialyzer sensing area further located upstream or downstream from the dialysate outlet pump, the from-dialyzer sensing area operable with the second non-invasive fluid velocity sensor when the disposable cassette is placed in the dialysis instrument.

17. The dialysis system of claim 16, which includes a logic implementer configured to determine a total amount of ultrafiltration removed from a patient using outputs from the first and second non-invasive fluid velocity sensors.

24. The dialysis system of claim 16, wherein the flexible sheet covers a side of the disposable cassette including the rigid outer wall of at least one of the to-dialyzer sensing area and the from-dialyzer sensing area.

29. The dialysis system of claim 16, wherein at least one of:

(i) the first pathway formed at least in part by the flexible sheet is adjacent to at least one of an inlet or an outlet of the to-dialyzer sensing area;

or (ii) the second pathway formed at least in part by the flexible sheet is adjacent to at least one of an inlet or an outlet of the from-dialyzer sensing area.

18. A dialysis system comprising:

a dialyzer;

a blood pump in fluid communication with the dialyzer;

a dialysate inlet pump in fluid communication with a dialysate inlet of the dialyzer;

a dialysate outlet pump in fluid communication with a dialysate outlet of the dialyzer;

a first non-invasive fluid velocity sensor positioned at a first rigid sensing area of a disposable cassette, the first rigid sensing area including rigid sidewalls and a rigid outer wall to sense an inlet velocity of dialysate pumped to the dialyzer inlet by the dialysate inlet pump, the first rigid sensing area located upstream or downstream from a first flexible pathway;

a second non-invasive fluid velocity sensor positioned at a second rigid sensing area of the disposable cassette, the second rigid sensing area including rigid sidewalls and a rigid outer wall to sense an outlet velocity of dialysate pumped from the dialyzer outlet by the dialysate outlet pump, the second rigid sensing area located upstream or downstream from a second flexible pathway; and

a logic implementer configured to determine a total amount of ultrafiltration removed from a patient using the sensed velocities from the first and second non-invasive fluid velocity sensors.

19. The dialysis system of claim 18, wherein the logic implementor is programmed to:

(i) subtract the sensed dialysate inlet velocity from the sensed dialysate outlet velocity to determine an instantaneous ultrafiltration velocity;

(ii) multiply the determined instantaneous ultrafiltration velocity by the cross-sectional area of the dialyzer inlet to determine an instantaneous ultrafiltration rate;

(iii) multiply the determined instantaneous ultrafiltration rate by a sample volume to determine an instantaneous ultrafiltration volume; and

(iv) integrate the determined instantaneous volume to determine the total amount of ultrafiltration removed from the patient.

20. The dialysis system of claim 18, wherein the logic implementer is programmed to:

(i) multiply a cross-sectional area of the dialyzer inlet by the sensed dialysate inlet velocity and by a sample time to determine a sample time inlet volume;

(ii) multiply a cross-sectional area of the dialyzer outlet by the sensed dialysate outlet velocity and by the sample time to determine a sample time outlet volume;

(iii) integrate the determined sample time inlet and outlet volumes over a treatment period to determine a total amount of dialysate delivered to and removed from the dialyzer during the treatment; and

(iv) subtract the total amount of dialysate delivered to the dialyzer from the total amount of dialysate removed from the dialyzer to determine the total amount of ultrafiltration removed from the patient.

25. The dialysis system of claim 18, which includes a flexible sheet that covers the rigid outer wall of at least one of the dialyzer inlet sensing area and the dialyzer outlet sensing area.

30. The dialysis system of claim 18, wherein at least one of:

(i) the first flexible pathway is adjacent to at least one of an inlet or an outlet of the first rigid sensing area;

or (ii) the second flexible pathway is adjacent to at least one of an inlet or an outlet of the second rigid sensing area.