Adaptive calibration pulsed oximetry method and device
First Claim
1. A method of calibrating an oximeter and determining an arterial blood oxygen saturation level in tissue, comprising:
- using a plurality of measurements to determine properties of a light transmission passing through or reflected from a tissue; and
using the properties of the light transmission or reflection to select a calibration curve, said calibration curve representing a level of arterial blood oxygen saturation in relation to a pulsatile factor;
wherein the plurality of measurements is obtained by varying a position of a light source or a light detector relative to the tissue to detect light passed through or reflected from different portions of the tissue.
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Abstract
A method for determining an arterial blood oxygen saturation level according to this invention includes measuring the light transmittance through tissue of light of a first wavelength and a second wavelength. A steady-state component of the measured light transmission is used to select an appropriate calibration curve. A pulsatile component of the measured light transmission is used to determine the arterial blood oxygen saturation level using the selected calibration curve. An oximetry system is also provided. An improved oximetry system is further provided wherein a plurality of light transmission measurements are used to determine a blood oxygen saturation level.
177 Citations
12 Claims
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1. A method of calibrating an oximeter and determining an arterial blood oxygen saturation level in tissue, comprising:
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using a plurality of measurements to determine properties of a light transmission passing through or reflected from a tissue; and
using the properties of the light transmission or reflection to select a calibration curve, said calibration curve representing a level of arterial blood oxygen saturation in relation to a pulsatile factor;
wherein the plurality of measurements is obtained by varying a position of a light source or a light detector relative to the tissue to detect light passed through or reflected from different portions of the tissue. - View Dependent Claims (2, 3)
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4. A method of calibrating an oximeter and determining an arterial blood oxygen saturation level in tissue, comprising:
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using a plurality of measurements to determine properties of a light transmission passing through or reflected from a tissue; and
using the properties of the light transmission or reflection to select a calibration curve, said calibration curve representing a level of arterial blood oxygen saturation in relation to a pulsatile factor;
wherein the plurality of measurements is obtained by modulating a light source being supplied to the tissue. - View Dependent Claims (5, 6, 7, 8, 9, 10)
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11. A method of calibrating an oximeter and determining an arterial blood oxygen saturation level in tissue, comprising:
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using a plurality of measurements to determine properties of a light transmission passing through or reflected from a tissue; and
using the properties of the light transmission or reflection to select a calibration curve, said calibration curve representing a level of arterial blood oxygen saturation in relation to a pulsatile factor;
wherein the properties of the light transmission comprise values for a plurality of variables, said variables comprising a vessel wall thickness, an average path length of photons, and optical properties of the tissue.
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12. A method of calibrating an oximeter and determining an arterial blood oxygen saturation level in tissue, comprising:
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using a plurality of measurements to determine properties of a light transmission passing through or reflected from a tissue;
using the properties of the light transmission or reflection to select a calibration curve, said calibration curve representing a level of arterial blood oxygen saturation in relation to a pulsatile factor; and
normalizing a steady-state component of the light transmission or reflection to remove the effects of variation of a strength of a light source and a sensitivity of a transducer from the steady-state component.
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Specification