Red blood cell spillover detection technique

• US 5,936,714 A
• Filed: 03/30/1998
• Issued: 08/10/1999
• Est. Priority Date: 11/06/1996
• Status: Expired due to Term

• Current Assignee: Terumo BCT, Inc. (Terumo Corporation)
• Original Assignee: Cobe Cardiovascular Incorporated (LivaNova Plc)
• Inventors: Gibbs, Bruce W.
• Primary Examiner(s): Kim, Robert H.
• Assistant Examiner(s): MERLINO, AMANDA H
• Application Number:
  US09/052,277
• Time in Patent Office: 498 Days
• Field of Search: 356/39-42, 356/246
• US Class Current: 356/39
• CPC Class Codes: A61M 1/3622 with a cassette forming partially or totally the blood circuit
• CPC Class Codes: A61M 1/367 Circuit parts not covered by the preceding subgroups of group A61M1/3621
• CPC Class Codes: A61M 2205/331 used as turbidity change detectors, e.g. for priming-blood or plasma-hemoglubine-interface detection
• CPC Class Codes: A61M 2205/3313 used specific wavelengths
• CPC Class Codes: G01N 21/3151 using two sources of radiation of different wavelengths G01N21/33 - G01N21/39 take precedence
• CPC Class Codes: G01N 21/532 with measurement of scattering and transmission
• CPC Class Codes: G01N 33/491 by separating the blood components G01N15/05 takes precedence

Abstract

An apparatus and a method are provided to monitor a generally transparent blood tube at a location that is downstream from a blood separator in order to detect the presence of red blood cells in a tube that is intended to carry a different blood component, for example platelets. A red light source and a green light source are located in relation to the tube so that red light emission and green light emission are directed toward the tube and toward the flowing blood component(s) that is carried within the tube. The red light source produces a red reflection intensity from red blood cells whose magnitude increases as a function of an increase in the concentration of red blood cells. The green light source produces a green reflection intensity from the red blood cells whose magnitude decreases as a function of an increase in the concentration of the red blood cells. These two light reflections are sensed by means of one broadband photodetector, or by two band-specific photodetectors, that are located on the same side of the tube, so as to be responsive only to reflected light. An output is provided by detecting the ratio of the magnitude of the red reflection intensity to the magnitude of the green reflection intensity.

Claims

1. Apparatus for monitoring a passageway of a cassette having an identification portion adjacent said passageway, wherein the passageway is adapted to carry a flow of first blood component and the apparatus is adapted for detecting the undesirable presence or spillover of a second blood component into the passageway flow, the apparatus comprising:

a first and a second light source physically located in relation to a side of the passageway so that light emission from said first light source and from said second light source are directed toward said side of the passageway, said first light source having a first wavelength that is selected to produce a first light reflection intensity from any second blood component that may be present in the passageway flow, the first light reflection intensity increasing as a function of an increase in concentration of the second blood component in the passageway flow, and said second light source having a second wavelength that is selected to produce a second light reflection intensity from any second blood component that may be present in the passageway flow, the second light intensity decreasing as a function of an increase in the concentration of the second blood component in the passageway flow;

a light intensity responsive photosensor operable to detect said first reflection intensity and said second reflection intensity; and

an output device controlled by said photosensor, wherein the apparatus is operative to identify the first blood component to flow in the passageway based upon a responsiveness to reflectivity of the identification portion of the cassette.

2. The apparatus of claim 1 wherein said output device operates to detect a ratio of said first reflection intensity to said second reflection intensity.

3. The apparatus of claim 2 wherein said first and second light sources are pulse energized during a first time interval and a second time interval, respectively, said photosensor operates to detect said first reflection intensity during said first time interval and to detect said second reflection intensity during said second time interval.

4. The apparatus of claim 1 wherein the second blood component is red blood cells, wherein said first light source is a red light source, and wherein said second light source is a green light source.

5. The apparatus of claim 4 wherein said output device detects a ratio of said first reflection intensity to said second reflection intensity.

6. The apparatus of claim 1 wherein said apparatus is responsive to the identification portion which is color coded.

7. The apparatus of claim 6 wherein the color coded identification portion is selected from the group consisting of black, gray and white.

8. The apparatus of claim 1 wherein the reflectivity of said identification portion is used by the apparatus to identify a feature of the cassette selected from the group consisting of (a) the nature of a disposable set which includes the cassette and (b) the blood components to be collected with the disposable set and the cassette.

9. A cassette to which is attached a tubing set and adapted for carrying a flow of a first blood component which is monitored by an apparatus adapted for detecting the undesirable presence or spillover of a second blood component into the flow of the first blood component flow, the cassette comprising:

a substantially transparent passageway formed in said cassette for receiving and conducting said first blood component flow; and

an identification portion of said cassette adjacent said passageway and having a identification portion reflectivity which is representative of information selected from the group consisting of (a) the identity of the first blood component;

(b) the nature of the tubing set; and

(c) the identity of the blood components to be collected with the tubing set.

10. The cassette of claim 9 wherein said identification portion is color-coded.

11. The cassette of claim 10 wherein said color-coded identification portion is a color-coded surface of a color selected from the group consisting of gray, white and black.

12. The cassette of claim 9 wherein said identification portion is a foil.

13. The cassette of claim 10 wherein said identification portion is a foil.

14. A cassette to which is attached a tubing set and having a passageway formed therein which is adapted for carrying a flow of a first blood component therethrough and for monitoring by an apparatus which detects the undesirable presence or spillover of a second blood component into the first blood component flow and comprises (i) a first and a second light source physically located in relation to a side of the passageway so that light emission from said first light source and from said second light source are directed toward said side of the passageway, said first light source having a first wavelength that is selected to produce a first light reflection intensity from any second blood component that may be present in the passageway flow, the first light reflection intensity increasing as a function of an increase in concentration of the second blood component in the passageway flow, and said second light source having a second wavelength that is selected to produce a second light reflection intensity from any second blood component that may be present in the passageway flow, the second light intensity decreasing as a function of an increase in the concentration of the second blood component in the passageway flow;

(ii) a light intensity responsive photosensor operable to detect said first reflection intensity and said second reflection intensity; and

(iii) an output device controlled by said photosensor;

said cassette passageway comprising;

an input passageway formed in said passageway in fluid communication with tubing containing the first blood component for receiving said first blood component from said tubing, said input passageway having an input passageway cross sectional area;

a chamber formed in said passageway in fluid communication with said input passageway, for receiving said first blood component from said input passageway, said chamber having a rectangular cross section with a chamber cross sectional area through which said first blood component flows and said photosensor detects said first and second reflection intensities; and

an exit passageway formed in said passageway and in fluid communication with said chamber, for collecting said first blood component from said chamber and passing said collected first blood component to a collection tubing, said exit passageway having an exit passageway cross sectional area, wherein said input passageway cross sectional area and said exit passageway cross sectional area are both less than said chamber cross sectional area.

15. Apparatus for monitoring a light transparent passageway adapted to carry flow of a first blood component, the apparatus comprising:

a first and a second light source physically located in relation to a side of the passageway so that light emission from said first light source and from said second light source are directed toward said side of the passageway, said first light source having a first wavelength which produces a baseline first light reflection intensity when first blood component is not flowing in the passageway, said second light source having a second wavelength which produces a baseline second light reflection intensity when first blood component is not flowing in the passageway, the first light reflection intensity and the second light reflection intensity both decreasing as a function of an increase in concentration of the first blood component flowing in the passageway;

a light intensity responsive photosensor operable to detect said first light reflection intensity and said second light reflection intensity; and

an output device controlled by said photosensor, wherein the apparatus is operative to monitor concentration of said first blood component.

16. The apparatus of claim 15 wherein said output device operates to detect a ratio of said first light reflection intensity to said second light reflection intensity.

17. The apparatus of claim 16 wherein said first light source and said second light source are pulse energized during a first time interval and a second time interval, respectively, and said photosensor operates to detect said first light reflection intensity during said first time interval and to detect said second light reflection intensity during said second time interval.

18. The apparatus of claim 15 wherein said first light source and said second light source are energized during a first time interval and a second time interval, respectively, wherein said photosensor operates to detect said first light reflection intensity during said first time interval and to detect said second light reflection intensity during said second time interval, and wherein said first light source and said second light source are pulse energized.

19. The apparatus of claim 15 wherein said first light source, said second light source, and said photosensor are all physically located adjacent to the same side of the passageway.

20. The apparatus of claim 19 wherein said output device detects a ratio of said first light reflection intensity to said second light reflection intensity.