Monitoring of tissue hemoglobin concentration
First Claim
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1. A method for monitoring tissue hemoglobin concentration using a medical device having an optical sensor, the method comprising;
- measuring light attenuation using the optical sensor positioned adjacent to a volume of tissue;
determining a value of a tissue scattering coefficient corresponding to the tissue volume in response to the attenuation measurement;
determining a second derivative of the light attenuation measurement;
computing an artifact correction term in response to the determined tissue scattering coefficient; and
computing a tissue hemoglobin concentration in response to the artifact correction term and the second derivative.
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Abstract
A medical device system and associated method monitor tissue hemoglobin concentration. Light attenuation is measured in a volume of tissue in a patient. A value of a tissue scattering coefficient corresponding to the tissue volume in the patient is established in response to the attenuation measurement. A second derivative of the light attenuation measurement is determined. An artifact correction term is computed in response to the established tissue scattering coefficient, and a tissue hemoglobin concentration is computed using the artifact correction term and the second derivative.
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Citations
21 Claims
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1. A method for monitoring tissue hemoglobin concentration using a medical device having an optical sensor, the method comprising;
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measuring light attenuation using the optical sensor positioned adjacent to a volume of tissue; determining a value of a tissue scattering coefficient corresponding to the tissue volume in response to the attenuation measurement; determining a second derivative of the light attenuation measurement; computing an artifact correction term in response to the determined tissue scattering coefficient; and computing a tissue hemoglobin concentration in response to the artifact correction term and the second derivative. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A medical device system for monitoring tissue hemoglobin concentration, comprising:
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an optical sensor to sense light attenuation in a volume of tissue; and a processor coupled to the optical sensor configured to measure light attenuation for at least four wavelengths, determine a value of a tissue scattering coefficient corresponding to the tissue volume in response to the measured light attenuation, determine a second derivative of the measured light attenuation, compute an artifact correction term in response to the determined tissue scattering coefficient, and compute a tissue hemoglobin concentration in response to the artifact correction term and the second derivative. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A computer-readable medium storing a set of instructions which cause a processor of an implantable medical device system including an optical sensor to:
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measure light attenuation in a volume of tissue, the light attenuation measurement comprising light attenuation measured for at least four wavelengths; determine a value of a tissue scattering coefficient corresponding to the tissue volume in response to the attenuation measurement; determine a second derivative of the light attenuation measurement; determine an artifact correction term in response to the established tissue scattering coefficient; and determine a tissue hemoglobin concentration using the artifact correction term and the second derivative.
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Specification