Claims
- 1. A method for use in a pulse oximetry system which provides a detector output indicative of light absorption by a tissue-under-test at each of a plurality of different light wavelengths and which employs the detector output to compute blood analyte indicator values for each of a plurality of measurements, said method comprising the steps of:
utilizing said detector output to obtain a corresponding relative motion estimate value for each of said plurality of measurements; and, determining:
(i) whether the corresponding relative motion estimate value for each of said plurality of measurements is within a first predetermined range, wherein for each measurement having a corresponding relative motion estimate value within the first predetermined range the corresponding blood analyte indicator value is adjusted in a first adjustment manner, and wherein said adjusted blood analyte indicator value is employable to obtain at least one blood analyte concentration value; (ii) whether the relative motion estimate value corresponding with each of said plurality of measurements is within a second predetermined range, non-overlapping with said first predetermined range, wherein for each measurement having a corresponding relative motion estimate value within said second predetermined range the corresponding blood analyte indicator value is employable to obtain at least one blood analyte concentration value without adjustment to the corresponding blood analyte indicator value; and (iii) whether the relative motion estimate value corresponding with each of said plurality of measurements is within a third predetermined range, non-overlapping with said first and second predetermined ranges, wherein for each measurement having a corresponding relative motion estimate value within the third predetermined range a previously determined blood analyte indicator value corresponding to a measurement within said first or second predetermined ranges is adjusted in a second adjustment manner different from said first adjustment manner, and
wherein said adjusted previously determined blood analyte indicator value is employable to obtain at least one blood analyte concentration value.
- 2. The method of claim 2 wherein, for each measurement having a corresponding relative motion estimate value within the third predetermined range, said second adjustment manner includes:
adjusting the previously determined blood analyte indicator value utilizing an adjustment factor.
- 3. The method of claim 2 further comprising:
utilizing said detector output signal to obtain moving average values of total tissue absorption of AC and DC signal components corresponding with each of said plurality of different light wavelengths, wherein said moving average values are determined for each of said plurality of measurements; computing a first ratio of the moving average values obtained for the measurement corresponding to the previously determined blood analyte indicator value; computing a second ratio of the moving average values obtained for the measurement having a corresponding relative motion estimate value within the third predetermined range; and computing the adjustment factor by dividing the first ratio by the second ratio to obtain a result and multiplying the result by a constant.
- 4. The method of claim 3 wherein said adjusting step includes:
multiplying the previously determined blood analyte indicator value by the adjustment factor.
- 5. The method of claim 3 wherein in said step of utilizing said detector output signal to obtain moving average values, a predetermined number of the measurements are utilized.
- 6. The method of claim 1 wherein, for each measurement having a corresponding relative motion estimate value within the first predetermined range, said first adjustment manner includes:
adjusting the corresponding blood analyte indicator value utilizing a predetermined adjustment factor.
- 7. The method of claim 6 wherein said adjusting step includes:
multiplying the corresponding blood analyte indicator value by said predetermined adjustment factor.
- 8. The method of claim 7, wherein said adjusting step further includes:
comparing the corresponding blood analyte indicator value to a predetermined threshold value, wherein said predetermined adjustment factor is scaled when said blood analyte indicator value exceeds said predetermined threshold value.
- 9. The method of claim 7, wherein said predetermined adjustment factor is set to a value between about 0.5 and 0.85.
- 10. A method for use in a pulse oximetry system which provides a detector output indicative of light absorption by a tissue-under-test at each of a plurality of different light wavelengths and which employs the detector output to compute blood analyte indicator values for each of a plurality of measurements, said method comprising the steps of:
utilizing said detector output to obtain a corresponding relative motion estimate value for each of said plurality of measurements; and, determining whether the relative motion estimate value corresponding with each of said plurality of measurements is within a predetermined range; and adjusting, for each measurement having a corresponding relative motion estimate value within the third predetermined range, a previously determined blood analyte indicator value corresponding to a measurement outside said predetermined range, wherein said adjusted previously determined blood analyte indicator value is employable to obtain at least one blood analyte concentration value.
- 11. The method of claim 10 wherein said adjusting step includes:
multiplying the previously determined blood analyte indicator value by an adjustment factor.
- 12. The method of claim 11 further comprising:
utilizing said detector output signal to obtain moving average values of total tissue absorption of AC and DC signal components corresponding with each of said plurality of different light wavelengths, wherein said moving average values are determined for each of said plurality of measurements; computing a first ratio of the moving average values obtained for the measurement corresponding to the previously determined blood analyte indicator value; computing a second ratio of the moving average values obtained for the measurement having a corresponding relative motion estimate value within the third predetermined range; and computing the adjustment factor by dividing the first ratio by the second ratio to obtain a result and multiplying the result by a constant.
- 13. The method of claim 12 wherein in said step of utilizing said detector output signal to obtain moving average values, a predetermined number of the measurements are utilized.
RELATED APPLICATION INFORMATION
[0001] This application is a continuation of U.S. patent application Ser. No. 09/675,596 entitled “PULSE OXIMETRY METHOD AND SYSTEM WITH IMPROVED MOTION CORRECTION” filed on Sep. 29, 2000, the entirety of which is hereby incorporated herein.
Continuations (1)
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Number |
Date |
Country |
Parent |
09675596 |
Sep 2000 |
US |
Child |
10217058 |
Aug 2002 |
US |