LACTATE CONCENTRATION MEASUREMENT DEVICE

• US 20090047177A1
• Filed: 08/17/2007
• Published: 02/19/2009
• Est. Priority Date: 08/17/2007
• Status: Abandoned Application

• Current Assignee: Nostix, LLC (Teleflex Incorporated)
• Original Assignee: Nostix, LLC (Teleflex Incorporated)
• Inventors: Repine, John E., Henry, Charles W., Nelson, Peter E., Dallmann, Devon J., Zellers, R. Dale, Walker, Stephen D.
• Application Number:
  US11/840,528
• Publication Number:
  US 20090047177A1
• Time in Patent Office: Days
• US Class Current: 422/55
• CPC Class Codes: G01N 2021/3166 using separate detectors and filters
• CPC Class Codes: G01N 21/314 with comparison of measurements at specific and non-specific wavelengths dual wavelength spectrometry G01J3/427
• CPC Class Codes: G01N 21/35 using infrared light G01N21/39 takes precedence

Abstract

A lactate concentration measurement apparatus comprising a housing enclosing a sample chamber configured for holding a body fluid sample and measurement photo-optics that generate light and monitor light intensity along a plurality of optical paths in the sample chamber. The apparatus further comprises a plurality of optical filters aligned in respective optical paths of the optical path plurality comprising at least a first optical filter with light absorption by lactate and water and a second optical filter with light absorption to water alone. A logic determines lactate concentration based on a ratio of intensities detected at a first detector in an optical path intersected by the first optical filter and detected at a second detector in an optical path intersected by the second optical filter.

Claims

1. A lactate concentration measurement apparatus comprising:

a housing enclosing a sample chamber configured for holding a body fluid sample;

measurement photo-optics that generate light and monitor light intensity along a plurality of optical paths in the sample chamber;

a plurality of optical filters aligned in respective optical paths of the optical path plurality comprising at least a first optical filter with light absorption by lactate and water and a second optical filter with light absorption to water alone; and

a logic that determines the lactate concentration based on a ratio of intensities detected at a first detector in an optical path intersected by the first optical filter and detected at a second detector in an optical path intersected by the second optical filter.

2. The apparatus according to claim 1 further comprising:

the measurement photo-optics comprise;

an emitter that emits light into the sample chamber; and

a plurality of detectors positioned along respective optical paths across the sample chamber from the emitter that detect emitted light intensity.

3. The apparatus according to claim 1 further comprising:

the first optical filter comprising a filter λ

1 with light absorption by lactate and water;

the second optical filter comprising a filter λ

2 with light absorption by water alone; and

the logic determines lactate concentration in the body fluid sample according to an equation as follows;

4. The apparatus according to claim 3 further comprising:

the first optical filter comprising a filter with a light absorption wavelength λ

1 of approximately 8.9 micrometers; and

the second optical filter comprising a filter with a light absorption wavelength λ

2 of approximately 8.4 micrometers.

5. The apparatus according to claim 3 further comprising:

the first optical filter comprising a filter with a light absorption wavelength λ

1 of approximately 8.3 micrometers; and

the second optical filter comprising a filter with a light absorption wavelength λ

2 of approximately 8.4 micrometers.

6. The apparatus according to claim 1 further comprising:

the housing enclosing a sample chamber configured for holding a body fluid sample comprising plasma, serum, saliva, cerebrospinal fluid, tears, urine, extracellular fluids, or other fluid from a body that does not contain red blood cells or hemoglobin.

7. The apparatus according to claim 1 further comprising:

the measurement photo-optics comprising;

the emitter configured to radiate broadband infrared light;

a parabolic reflector separated by an air gap from the emitter that collimates the radiated broadband infrared light; and

a plurality of detectors positioned along respective optical paths across the sample chamber from the emitter that detect emitted light intensity, wherein

the housing emitter, and detector plurality are arranged whereby optical path lengths are in an approximate range of 10-50 micrometers.

8. The apparatus according to claim 1 further comprising:

the first and second optical filters comprising narrowband filters with a center wavelength variability of ±

2%, a half power bandwidth of 0.12 micrometers, and peak transmission of 85%.

9. The apparatus according to claim 1 further comprising:

the housing enclosing the sample chamber is formed of a material that is nonabsorbent to 8-10 micrometer light and is sufficiently rigid to maintain 10-50 micrometer spacing, and remains solid when contacted by body fluid.

10. The apparatus according to claim 1 further comprising:

the housing enclosing the sample chamber is formed of high density polyethylene (HDPE) that has a transmission of approximately 53% at approximately 8.3, 8.4 and 8.9 micrometers.

11. The apparatus according to claim 1 further comprising:

a display coupled to the housing whereby a lactate measurement is locally determined and displayed within the housing and the body fluid sample is continuously contained within a closed loop including the lactate concentration measurement apparatus and a patient'"'"'s body.

12. The apparatus according to claim 1 further comprising:

a display coupled to the housing; and

the logic that determines a lactate measurement in real-time for real-time presentation on the display.

13. The apparatus according to claim 1 further comprising:

a fluid loop that couples the sample chamber to a patient'"'"'s body fluid system;

a controllable infusion pump coupled to the fluid loop; and

the logic that controls, with logic automation, the infusion pump for administration of therapeutic fluids into the fluid loop based on the lactate concentration.

14. A method for measuring concentration of lactate in body fluid comprising:

acquiring a body fluid sample;

emitting light into the body fluid sample;

detecting emitted light intensity on a plurality of optical paths through the body fluid sample;

arranging a plurality of optical filters in respective optical paths of the optical path plurality comprising at least a first optical filter with light absorption by lactate and water and a second optical filter with light absorption to water alone;

measuring the detected light intensity passed through the first optical filter;

measuring the detected light intensity passed through the second optical filter;

determining lactate concentration based on a ratio of intensities detected at a detector in an optical path intersected by the first optical filter and detected at a detector in an optical path intersected by the second optical filter.

15. The method according to claim 14 further comprising:

measuring lactate concentration in body fluid;

arranging the optical filters including the first optical filter comprising a filter λ

1 with light absorption by lactate and water, and the second optical filter comprising a filter λ

2 with light absorption by water alone; and

determining lactate concentration in the body fluid sample according to an equation as follows;

16. The method according to claim 15 further wherein:

the first optical filter comprises a filter with a light absorption wavelength λ

1 of approximately 8.9 micrometers; and

the second optical filter comprises a filter with a light absorption wavelength λ

2 of approximately 8.4 micrometers.

17. The method according to claim 15 wherein:

the first optical filter comprises a filter with a light absorption wavelength λ

1 of approximately 8.3 micrometers; and

the second optical filter comprises a filter with a light absorption wavelength λ

2 of approximately 8.4 micrometers.

18. The method according to claim 14 further comprising:

acquiring the body fluid sample comprising plasma, serum, saliva, cerebrospinal fluid, tears, urine, extracellular fluids, or other fluid from a body that does not contain red blood cells or hemoglobin.

19. The method according to claim 14 further comprising:

acquiring the body fluid sample in a closed body loop;

locally determining a lactate measurement in the closed body loop; and

displaying the lactate measurement local to the closed body loop.

20. The method according to claim 14 further comprising:

determining a lactate measurement in real-time; and

displaying the lactate measurement in real-time.

21. The method according to claim 14 further comprising:

acquiring the body fluid sample in a closed body loop;

pumping a therapeutic fluid into the closed body loop; and

controlling, with logic automation, pumping for administration of therapeutic fluids into the fluid loop based on the lactate concentration.

22. A lactate concentration measurement apparatus comprising:

a housing enclosing a sample chamber configured for holding a body fluid sample;

measurement photo-optics that generate light and monitor light intensity along an optical path in the sample chamber;

a first optical filter with light absorption by a lactate and water;

a second optical filter with light absorption to water alone;

a switch that alternately interposes the first optical filter and the second optical filter into the optical path; and

a logic that determines lactate concentration based on a ratio of intensities detected with the first optical filter and the second optical filter interposed into the optical path.

23. The apparatus according to claim 22 further comprising:

the measurement photo-optics comprising;

an emitter that emits light along an optical path into the sample chamber; and

a detector positioned along the optical path across the sample chamber from the emitter that detects emitted light intensity.

24. The apparatus according to claim 22 further comprising:

the first optical filter comprising a filter λ

1 with light absorption by lactate and water;

the second optical filter comprising a filter λ

2 with light absorption by water alone; and

the logic determines lactate concentration in the body fluid sample according to an equation as follows;

25. The apparatus according to claim 24 further comprising:

the first optical filter comprising a filter with a light absorption wavelength λ

1 of approximately 8.9 micrometers; and

the second optical filter comprising a filter with a light absorption wavelength λ

2 of approximately 8.4 micrometers.

26. The apparatus according to claim 24 further comprising:

the first optical filter comprising a filter with a light absorption wavelength λ

1 of approximately 8.3 micrometers; and

the second optical filter comprising a filter with a light absorption wavelength λ

2 of approximately 8.4 micrometers.

27. The apparatus according to claim 22 further comprising:

the housing enclosing a sample chamber configured for holding a body fluid sample comprising plasma, serum, saliva, cerebrospinal fluid, tears, urine, extracellular fluids, or other fluid from a body that does not contain red blood cells or hemoglobin.

28. The apparatus according to claim 22 further comprising:

the measurement photo-optics comprising;

an emitter configured to radiate broadband infrared light;

a parabolic reflector separated by an air gap from the emitter that collimates the radiated broadband infrared light; and

a detector;

wherein

the housing, emitter, and detector are arranged whereby optical path length is in an approximate range of 10-50 micrometers.

29. The apparatus according to claim 22 further comprising:

the switch comprising a sliding filter holder whereby light passes through a selected filters held by the sliding filter holder over the detector.

30. The apparatus according to claim 22 further comprising:

the first and second optical filters comprising narrowband filters with a center wavelength variability of ±

2%, a half power bandwidth of 0.12 micrometers, and peak transmission of 85%.

31. The apparatus according to claim 22 further comprising:

the housing enclosing the sample chamber is formed of a material that is nonabsorbent to 8-10 micrometer light and is sufficiently rigid to maintain 10-50 micrometer spacing, and remains solid when contacted by body fluid.

32. The apparatus according to claim 22 further comprising:

the housing enclosing the sample chamber is formed of high density polyethylene (HDPE) that has a transmission of approximately 53% at approximately 8.3, 8.4 and 8.9 micrometers.

33. The apparatus according to claim 22 further comprising:

a display coupled to the housing whereby a lactate measurement is locally determined and displayed within the housing and the body fluid sample is continuously contained within a closed loop including the lactate concentration measurement apparatus and a patient'"'"'s body.

34. The apparatus according to claim 22 further comprising:

a display coupled to the housing; and

the logic that determines a lactate measurement in real-time for real-time presentation on the display.

35. The apparatus according to claim 22 further comprising:

a fluid loop that couples the sample chamber to a patient'"'"'s body fluid system;

a controllable infusion pump coupled to the fluid loop; and

the logic that controls, with logic automation, the infusion pump for administration of therapeutic fluids into the fluid loop based on the lactate concentration.

36. A method for measuring concentration of lactate concentration in body fluid comprising:

acquiring a body fluid sample;

emitting light along an optical path into the body fluid sample;

detecting emitted light intensity on the optical path through the body fluid sample;

positioning a first optical filter with light absorption by lactate and water in the optical path;

measuring the detected light intensity passed through the first optical filter;

replacing the first optical filter with a second optical filter with light absorption to water alone;

measuring the detected light intensity passed through the second optical filter; and

determining lactate concentration based on a ratio of intensities detected with the first optical filter and the second optical filter interposed into the optical path.

37. The method according to claim 36 further comprising:

measuring lactate concentration in body fluid;

positioning the first optical filter comprising a filter λ

1 with light absorption by lactate and water;

replacing the first optical filter with the second optical filter comprising a filter λ

2 with light absorption by water alone; and

determining lactate concentration in the body fluid sample according to an equation as follows;

38. The method according to claim 37 further wherein:

the first optical filter comprises a filter with a light absorption wavelength λ

1 of approximately 8.9 micrometers; and

the second optical filter comprises a filter with a light absorption wavelength λ

2 of approximately 8.4 micrometers.

39. The method according to claim 37 wherein:

the first optical filter comprises a filter with a light absorption wavelength λ

1 of approximately 8.3 micrometers; and

the second optical filter comprises a filter with a light absorption wavelength λ

2 of approximately 8.4 micrometers.

40. The method according to claim 36 further comprising:

acquiring the body fluid sample comprising plasma, serum, saliva, cerebrospinal fluid, tears, urine, extracellular fluids, or other fluid from a body that does not contain red blood cells or hemoglobin.

41. The method according to claim 36 further comprising:

acquiring the body fluid sample in a closed body loop;

locally determining a lactate measurement in the closed body loop; and

displaying the lactate measurement local to the closed body loop.

42. The method according to claim 36 further comprising:

determining a lactate measurement in real-time; and

displaying the lactate measurement in real-time.

43. The method according to claim 36 further comprising:

acquiring the body fluid sample in a closed body loop;

pumping a therapeutic fluid into the closed body loop; and

controlling, with logic automation, pumping for administration of therapeutic fluids into the fluid loop based on the lactate concentration.