Systems and methods for sensing red blood cell hematocrit

• US 6,419,822 B2
• Filed: 07/10/2001
• Issued: 07/16/2002
• Est. Priority Date: 09/03/1999
• Status: Expired due to Term

• Current Assignee: Fenwal Incorporated (Fresenius SE & Co. KGaA)
• Original Assignee: Baxter International Inc.
• Inventors: Vandlik, Mark R., Joie, Michel L. F., Muller, Matthew R.
• Primary Examiner(s): Drodge, Joseph W.
• Application Number:
  US09/901,986
• Publication Number:
  US 20020011449A1
• Time in Patent Office: 371 Days
• Field of Search: 210/85, 210/94, 210/360.1, 210/512.1, 210/739, 210/745, 210/767, 210/787, 210/143, 494/1, 494/10, 494/37, 422/82.05, 436/264, 436/265, 604/4.01, 604/5.01, 604/6.01, 604/6.02, 604/6.09
• US Class Current: 210/94
• CPC Class Codes: A61M 1/0236 with sampling means, e.g. sample bag or sampling port
• CPC Class Codes: A61M 1/362227 the interface providing means for actuating on functional elements of the cassette, e.g. plungers
• CPC Class Codes: A61M 1/36225 with blood pumping means or components thereof
• CPC Class Codes: A61M 1/362261 at least one cassette surface or portion thereof being flexible, e.g. the cassette having a rigid base portion with preformed channels and being covered with a foil
• CPC Class Codes: A61M 1/362262 Details of incorporated reservoirs
• CPC Class Codes: A61M 1/362264 the filter being a blood filter
• 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 1/367 Circuit parts not covered by the preceding subgroups of group A61M1/3621
• 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 1/38 Removing constituents from donor blood and storing or returning remainder to body , e.g. for transfusion
• CPC Class Codes: A61M 2205/128 with incorporated valves
• CPC Class Codes: A61M 2205/3393 by weighing the reservoir
• CPC Class Codes: A61M 2230/207 hematocrit
• CPC Class Codes: B01D 17/0217 by centrifugal force
• CPC Class Codes: B01D 21/2444 Discharge mechanisms for the classified liquid
• CPC Class Codes: B01D 21/245 Discharge mechanisms for the sediments
• CPC Class Codes: B01D 21/26 Separation of sediment aided by centrifugal force or centripetal forcecentrifuges B04B; cyclones B04C
• CPC Class Codes: B01D 21/262 by using a centrifuge
• CPC Class Codes: B01D 21/302 Active control mechanisms with external energy, e.g. with solenoid valve
• CPC Class Codes: B01D 21/34 : Controlling the feed distribution; Controlling the liquid level ; Control of process parameters
• CPC Class Codes: B01D 2221/08 : Mobile separation devices
• CPC Class Codes: B01D 2221/10 : Separation devices for use in medical, pharmaceutical or laboratory applications, e.g. separating amalgam from dental treatment residues

Abstract

Red blood cell sensing systems and methods rely upon straightforward measurement geometries. The systems and methods comprise an incident light source, an optical sensor, and a blood collection tube. The systems and methods hold the blood collection tube a predetermined radial distance from the incident light source where a linear relationship exists between sensed reflected light measured by the optical sensor and red blood cell hematocrit in a range of at least 10 to 90. The systems and methods make possible accurate red blood sensing without use of special optical cuvettes, mirrors, or focusing lenses. The systems and methods also make possible the use of standard transparent plastic tubing, without reliance upon special optical cuvettes.

Claims

1. A blood processing system comprising

a separation chamber for processing blood to obtain a blood suspension containing a quantity of red blood cells,

a sensing assembly outside the separation chamber to optically sense presence of red blood cells, and

a fluid circuit including an umbilicus coupled to the separation chamber, a blood inlet tube extending beyond the umbilicus outside the separation chamber for conveying a flow of blood into the umbilicus, a component collection tube extending beyond the umbilicus outside the separation chamber for conveying a flow of the blood suspension from the umbilicus, and a fixture including a holder to hold the blood inlet tube and the component collection tube in an adjacent, spaced-apart relationship for handling as a bundle outside the separation chamber, the fixture being movable into releasable engagement with the sensing assembly outside the separation chamber to hold the component collection tube within the holder in a predetermined relationship with the sensing assembly so that presence of red blood cells in the component collection tube can be sensed.

2. A blood processing system according to claim 1

wherein the fixture directs the blood inlet tube and the component collection tube through a bend without substantial kinking.

3. A blood processing system according to claim 1

further including a controller communicating with the sensing assembly to control flow of blood suspension through the component collection tube in response to sensing by the sensing assembly.

8. A blood processing system according to claim 1 or 4

wherein the fixture comprises an integral part of the fluid circuit.

9. A blood processing system according to claim 1 or 4

wherein the fixture is a separately fabricated part of the fluid circuit.

4. A blood processing system comprising

a separation chamber for processing blood to obtain first and second blood suspensions,

a sensing station outside the separation chamber including a first sensor assembly that operates to optically monitor presence of at least one blood component in the first blood suspension, and a second sensor assembly that operates to optically monitor presence of at least one blood component in the second blood suspension,

a fluid circuit including an umbilicus coupled to the separation chamber, a blood inlet blood into the umbilicus, a first component collection tube extending beyond the umbilicus outside the separation chamber for conveying a flow of the first component from the umbilicus, and a second component collection tube extending beyond the umbilicus outside the separation chamber for conveying a flow of the second component from the separation chamber, and

a fixture including a holder to hold the first component collection tube and the second component collection tube in an adjacent, spaced-apart relationship for handling as a bundle outside the separation chamber, the fixture being movable into releasable engagement with the sensing station to hold the first component collection tube and the second component collection tube within the holder in predetermined relationships with the first sensor assembly and the second sensor assembly, respectively, so that so that presence of blood components in the respective first and second component collection tubes can be sensed.

5. A blood processing system according to claim 4

wherein the fixture directs the first and second component collection tubes through a bend without substantial kinking.

6. A blood processing system according to claim 4

wherein the holder holds the blood inlet tube for handling as a bundle outside the separation chamber with the first and second component collection tubes.

7. A blood processing system according to claim 4

further including a controller communicating with the first and second sensor assemblies to affect flow of first and second blood suspensions through the first and second component collection tubes in response to sensing by the first and second sensor assemblies.