Shrouded sensor clip assembly and blood chamber for an optical blood monitoring system

• US 8,517,968 B2
• Filed: 02/25/2011
• Issued: 08/27/2013
• Est. Priority Date: 02/25/2011
• Status: Active Grant

• Current Assignee: Fresenius Medical Care Holdings Incorporated (Fresenius Medical Care AG)
• Original Assignee: Fresenius Medical Care Holdings Incorporated (Fresenius Medical Care AG)
• Inventors: Barrett, Louis L., Law, Perry N.
• Primary Examiner(s): DEAK, LESLIE R
• Application Number:
  US13/034,788
• Publication Number:
  US 20120220914A1
• Time in Patent Office: 914 Days
• Field of Search: 604/4.01, 604/5.01, 604/5.04, 604/6.09, 356 39- 40
• US Class Current: 604/6.09
• CPC Class Codes: A61B 2562/185 Optical shielding, e.g. baffles
• CPC Class Codes: A61B 5/14535 for measuring haematocrit
• CPC Class Codes: A61B 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/14557 specially adapted to extracorporeal circuits
• CPC Class Codes: A61M 1/367 Circuit parts not covered by the preceding subgroups of group A61M1/3621
• CPC Class Codes: A61M 2205/3306 Optical measuring means
• CPC Class Codes: A61M 2205/3313 used specific wavelengths
• CPC Class Codes: A61M 2230/205 partial oxygen pressure (P-O2)
• CPC Class Codes: A61M 2230/207 hematocrit
• CPC Class Codes: A61M 39/10 Tube connectors; Tube couplings A61M39/02 takes precedence; connecting needles to syringes or hubs A61M5/34; connecting catheter tubes to hubs A61M25/0014

Abstract

An optical blood monitoring system includes a sensor clip assembly and a blood chamber. The blood chamber has an internal flow cavity for extracorporeal blood flow and viewing lenses to enable the sensor clip assembly to monitor the blood when it is mounted on the blood chamber. The sensor clip assembly includes an annular shroud surrounding the LED emitters and another annular shroud surrounding the photodetectors, both for the purpose of blocking ambient light and limiting light piping. The blood chamber includes separate, distinct shroud mating surfaces to engage the shrouds on the sensor clip assembly.

Claims

1. A blood chamber for use in an optical blood monitoring system having a sensor clip assembly with first shroud surrounding photoemitters on one side of the sensor clip assembly and a second shroud surrounding photodetectors on the other side of the sensor clip assembly, the blood chamber comprising:

an inlet, an outlet and an internal blood flow cavity;

a first exterior side having a first viewing area and a separate, distinct shroud mating surface located outside of the first viewing area, the shroud mating surface on the first exterior side being adapted to engage a shroud on a sensor clip assembly when the sensor clip assembly is clipped on to the blood chamber;

a second exterior side having a second viewing area and a separate, distinct shroud mating surface located outside of the second viewing area, the shroud mating surface on the second exterior side being adapted to engage a shroud on a sensor clip assembly when the sensor clip assembly is clipped over the blood chamber;

an upstanding wall on the second exterior side outside of the second viewing area and separating the second viewing area from the shroud mating surface on the second exterior side of the blood chamber such that a well is formed around the second viewing area, a floor of the well being the shroud mating surface on the second exterior side of the blood chamber;

wherein each of the first and second viewing areas has a substantially flat exterior surface that is parallel to and aligned with the other viewing area.

2. The blood chamber as recited in claim 1 further comprising:

a molded chamber body that includes the inlet and the outlet;

a first molded lens body that includes the first exterior side with the first viewing area; and

a second molded lens body that includes the second exterior side with the second viewing area;

wherein the first and second molded lens bodies are attached to the molded chamber body during the manufacturing of the blood chamber.

3. The blood chamber as recited in claim 1 wherein at least one anti-rotation tab is formed on the first exterior side, said anti-rotation tab being adapted to inter-engage with a slot on a shroud of a sensor clip assembly.

4. The blood chamber as recited in claim 3 wherein the anti-rotation tab is raised above the viewing area on the first side of the blood chamber.

5. The blood chamber as recited in claim 1 wherein the exterior surface of the first viewing area is raised above the shroud mating surface such that a well is formed around the raised viewing area, the floor of the well being the shroud mating surface on the first exterior side of the blood chamber.

6. The blood chamber as recited in claim 1 wherein the exterior surface of the second viewing area and the shroud mating surface on the second exterior side of the blood chamber are located at substantially the same depth relative to the upstanding wall.

7. The blood chamber as recited in claim 1 wherein:

the exterior surface of the first viewing area is raised above the shroud mating surface on the first exterior side of the blood chamber such that a well is formed around the raised viewing area; and

the height of the raised viewing area on the first exterior side of the blood chamber above the well on the first exterior side of the blood chamber is substantially equal to the height of the wall on the second exterior side of the blood chamber.

8. The blood chamber as recited in claim 1 wherein the viewing areas are circular.

9. The blood chamber as recited in claim 8, wherein the shroud mating surfaces are annular.

10. The blood chamber as recited in claim 1 further comprising:

a molded chamber body that includes the inlet, outlet and the first exterior side with the first viewing area; and

a molded lens body that includes the second exterior side with the second viewing area;

wherein the molded lens body is attached to the molded chamber body as part of manufacturing the blood chamber.

11. The blood chamber as recited in claim 10, wherein the first viewing area of the chamber body comprises a clear polycarbonate material and the remainder of the molded chamber body comprises an opaque polycarbonate material.

12. The blood chamber as recited in claim 11, wherein the molded lens body is made entirely from clear polycarbonate material and is attached to the chamber body during the manufacturing process.

13. An optical blood monitoring system comprising:

extracorporeal tubing for passing blood drawn from a patient;

a blood chamber for receiving blood flowing through the extracorporeal tubing, the blood chamber defining a flow path through an internal blood flow cavity and providing a viewing area for optical monitoring of the blood, the blood chamber including;

an inlet, an outlet and an internal blood flow cavity;

a first exterior side having a viewing area and a separate, distinct shroud mating surface located outside of the viewing area, the distinct shroud mating surface being adapted to engage a shroud of a sensor clip assembly when the sensor clip assembly is clipped onto the blood chamber;

a second exterior side having a viewing area and a separate, distinct shroud mating surface located outside of the viewing area, the distinct shroud mating surface being adapted to engage a shroud of a sensor clip assembly when the sensor clip assembly is clipped onto the blood chamber;

wherein each viewing area has a substantially flat exterior surface that is parallel to and aligned with the other viewing area; and

a sensor clip assembly that monitors the patient'"'"'s blood flowing through the blood chamber, the sensor assembly comprising;

an emitter subassembly with a first photoemitter for emitting light at a first wavelength (λ

1) through the viewing areas and blood flowing through the internal blood flow cavity of the blood chamber and a second photoemitter for emitting light at a second wavelength (λ

2) through the viewing areas and blood flowing through the internal blood flow cavity of the blood chamber;

a detector subassembly with at least one photodetector for detecting the intensity of the light at each of the first (λ

1) and second (λ

2) wavelengths after the light passes through the viewing areas and blood flowing through the internal blood flow cavity of the blood chamber;

an emitter shroud on the emitter subassembly surrounding the photoemitters and extending away from the emitter subassembly to a distance beyond a diffusing lens associated with the photoemitters and towards the detector subassembly to prevent at least ambient light from entering the blood chamber through a viewing area when the sensor clip assembly is clipped onto the blood chamber; and

a detector shroud on the detector subassembly surrounding the photodeteetors and extending away from the detector subassembly to a distance beyond a diffusing lens associated with the at least one photodetector and toward the emitter subassembly to prevent at least ambient light from entering the blood chamber through a viewing area when the sensor clip assembly is clipped onto the blood chamber.

14. The system as recited in claim 13 further including a controller having a ratiometric model to calculate a hematocrit value (HCT) of the blood drawn from the patient and passing through the extracorporeal tubing and blood chamber, said ratiometric model to calculate the hematocrit value (HCT) being of the following form:

15. The system as recited in claim 14 wherein the emitter subassembly contains a third photoemitter for emitting infrared light at a third wavelength (λ

3) through the viewing areas and blood flowing through the internal blood flow cavity of the blood chamber and wherein the photodetector is capable of detecting the intensity of the light at the third wavelength (λ

3) after the light passes through the viewing areas and blood flowing through the internal blood flow cavity of the blood chamber.

16. The system as recited in claim 15 wherein the controller contains a second ratiometric model to calculate oxygen saturation level (SAT), of the blood drawn from the patient in passing through the extracorporeal tubing and blood chamber, said second ratiometric model to calculate oxygen saturation level (SAT) being of the following form:

17. The system as recited in claim 13 wherein each annular shroud is stepped with an inner annular step surface being positioned at a distance away from the respective subassembly that is less than distance that an outer annular step surface is positioned away from the respective subassembly.

18. The system as recited in claim 17 wherein the surface area of the outer annular step surface is substantially equal to the surface area of the shroud mating surface on the blood chamber.

19. The system as recited in claim 18 wherein the first exterior side of the blood chamber includes an anti-rotation tab.

20. The system as recited in claim 19 wherein at least one shroud contains a slot shaped to engage the anti-rotation tab.

21. The system as recited in claim 19 wherein both shrouds contain a slot shaped to engage the anti-rotation tab.

22. The system as recited in claim 13 wherein the viewing areas on the blood chamber are circular and the shrouds on the sensor clip are annular.

23. The system as recited in claim 22 wherein:

the exterior surface of the first viewing area on the blood chamber is raised above the shroud mating surface such that an annular well is formed around the raised viewing area;

the exterior surface of the second viewing area on the blood chamber is surrounded by an upstanding wall that separates the second viewing area from the shroud mating surface on the second exterior side of the blood chamber such that an annular well is formed around the second viewing area; and

each annular shroud on the sensor clip assembly is stepped and an inner annular step surface being positioned at a distance away from the respective subassembly that is less than a distance that an outer annular step surface is positioned away from the respective subassembly, said distance being substantially equal to the height of the wall on the second exterior side of the blood chamber and substantially equal to the height of the raised viewing area on the first exterior side of the blood chamber above the surrounding annular well.

24. The optical blood monitoring system as recited in claim 13 wherein at least one anti-rotation tab is formed on the first exterior side of the blood chamber, said at least one anti-rotation tab being adapted to inter-engage with at least one slot on the shroud of the sensor clip assembly.

25. The optical blood monitoring system as recited in claim 13 wherein an upstanding wall on the second exterior side of the blood chamber surrounds the second viewing area and separates the second viewing area from the shroud mating surface on the second exterior side of the blood chamber such that a well is formed around the second viewing area, the floor of the well being the shroud mating surface on the second exterior side of the blood chamber.

26. The optical blood monitoring system as recited in claim 13, wherein the blood chamber includes a molded chamber body comprising a polycarbonate material that is tinted blue and a molded lens body comprising a clear polycarbonate.

27. A method for monitoring at least one blood constituent, the method comprising:

connecting a blood chamber to extracorporeal tubing through which a patient'"'"'s blood flows, said blood chamber having a body including an internal blood flow cavity between a first viewing area and a second viewing area;

attaching a sensor clip assembly having art emitter subassembly and a detector subassembly to the blood chamber so as to limit rotation of the sensor clip assembly relative to the blood chamber by engaging one or more anti-rotational tabs formed on the blood chamber with one or more slots formed in a shroud on the sensor clip assembly;

emitting light from the emitter subassembly at a first wavelength through the blood chamber and the patient'"'"'s blood flowing through the blood chamber;

emitting light from the emitter subassembly at a second wavelength through the blood chamber and the patient'"'"'s blood flowing through the blood chamber;

detecting the intensity of the light at the first wavelength with the detector subassembly after it has passed through the blood chamber and the patient'"'"'s blood flowing therethrough;

detecting the intensity of the light at the second wavelength, with the detector subassembly after it passes through the blood chamber and the blood flowing therethrough;

calculating a concentration or value of a blood constituent from at least the detected light intensity at the first wavelength and the detected light intensity at the second wavelength; and

limiting ambient light from entering the first and second viewing areas and limiting light emitted from the emitter subassembly from ducting through the body of the blood chamber to the detector subassembly by surrounding the first viewing area with the shroud, where the shroud is a first shroud, and by surrounding the other of the first and second viewing areas with a second shroud.

28. The method for monitoring at least one blood constituent as recited in claim 27, wherein attaching the sensor clip assembly to the blood chamber so as to limit relative rotation of the sensor clip assembly and the blood chamber includes engaging one or more anti-rotational tabs formed on the blood chamber with one or more slots formed in a shroud on the sensor clip assembly.

29. A blood chamber for use in an optical blood monitoring system having a sensor clip assembly with first shroud surrounding photoemitters on one side of the sensor clip assembly and a second shroud surrounding photodetectors on the other side of the sensor clip assembly, the blood chamber comprising:

an inlet, an outlet and an internal blood flow cavity;

first and second exterior sides each having a viewing area and a separate and distinct shroud mating surface located outside of the viewing area, where the shroud mating surface on the first exterior side is adapted to engage a shroud on a sensor clip assembly when the sensor clip assembly is clipped on to the blood chamber;

one or more anti-rotation tabs formed on at least one of the first and second exterior sides, said one or more anti-rotation labs being adapted to inter-engage with one or more slots on the shroud of the sensor clip assembly;

wherein each of the viewing areas has a substantially flat exterior surface that is parallel to and aligned with the other viewing area.

30. The blood chamber as recited in claim 29 wherein the viewing areas are first and second viewing areas, the blood chamber further comprising:

a molded chamber body that includes the inlet and the outlet;

a first molded lens body that includes the first exterior side with the first viewing area; and

a second molded lens body that includes the second exterior side with the second viewing area;

wherein the first and second molded lens bodies are attached to the molded chamber body during the manufacturing of the blood chamber.

31. The blood chamber as recited in claim 30, wherein the first viewing area of the chamber body comprises a clear polycarbonate material and the remainder of the molded chamber body comprises a blue-tinted polycarbonate material.

32. A blood chamber as recited in claim 31, wherein each of the first and second molded lens body is made entirely from clear polycarbonate material and is attached to the chamber body during the manufacturing process.

33. The blood chamber as recited in claim 29 wherein the anti-rotation tab is raised above the viewing area.

34. The blood chamber as recited in claim 29 including an upstanding wall on the second exterior side outside of the viewing area and separating the viewing area from the shroud mating surface on the second exterior side of the blood chamber such that a well is formed around the viewing area, a floor of the well being the shroud mating surface on the second exterior side of the blood chamber.

35. The blood chamber as recited in claim 34 wherein the exterior surface of the viewing area and the shroud mating surface of the second exterior side of the blood chamber are located at substantially the same depth relative to the upstanding wall.

36. A blood chamber for use in an optical blood monitoring system having a sensor clip assembly with first shroud surrounding photoemitters on one side of the sensor clip assembly and a second shroud surrounding photodetectors on the other side of the sensor clip assembly, the blood chamber comprising:

a chamber body that includes an inlet, an outlet and an internal blood flow cavity;

first and second exterior sides of the chamber body each having a viewing area and a separate and distinct shroud mating surface located outside of the viewing area, where the shroud mating surface on the first exterior side is adapted to engage a shroud on a sensor clip assembly when the sensor clip assembly is clipped on to the blood chamber; and

first and second lens bodies, which include the viewing areas, comprising a clear polycarbonate material and the remainder of the molded chamber body comprising a blue-tinted polycarbonate material;

wherein each of the viewing areas has a substantially flat exterior surface that is parallel to and aligned with the other viewing area.

37. The blood chamber as recited in claim 36, wherein each of the first and second lens bodies is attached to the chamber body during a manufacturing process.

38. The blood chamber as recited in claim 36 including one or more anti-rotation tabs formed on at least one of the first and second exterior sides, said one or more anti-rotation tabs being adapted to inter-engage with one or more slots on the shroud of a sensor clip assembly.

39. The blood chamber as recited in claim 38 wherein the one or more anti-rotation tabs is raised above the viewing area.

40. The blood chamber as recited in claim 36 including an upstanding wall on the second exterior side outside of the viewing area and separating the viewing area from the shroud mating surface on the second exterior side of the blood chamber such that a well is formed around the viewing area, a floor of the well being the shroud mating surface on the second exterior side of the blood chamber.

41. The blood chamber as recited in claim 40 wherein the exterior surface of the viewing area and the shroud mating surface of the second exterior side of the blood chamber are located at substantially the same depth relative to the upstanding wall.