Reliable noninvasive measurement of blood gases
AssigneeSandia Corporation
InventorsEdward V. Thomas, Mark R. Robinson, David M. Haaland, Mary K. Alam
Life of this patent
Estimating the term…
Abstract
This invention relates to methods and apparatus for, preferably, determining non-invasively and in vivo at least two of the five blood gas parameters (i.e., pH, [HCO.sub.3.sup.- ], PCO.sub.2, PO.sub.2, and O.sub.2 sat.) in a human.
Claims36
A quantitative analysis instrument for noninvasive measurement of two or more blood gas parameters present in blood containing tissue of a human, said instrument comprising:
- a. a source of at least three different wavelengths of light, said wavelengths being in the range of 500 to 2500 nm;
- b. optics for directing said wavelengths of light into said tissue;
- c. at least one detector for measuring the intensities of at least a portion of said wavelengths of said light emerging from said tissue at, at least, three wavelengths of said light during the systolic and diastolic portions of the cardiac cycle;
- d. electronics for processing said measured intensities to estimate the values at least two of pH, PCO.sub.2, and [HCO.sub.3.sup.- ] and a measure of oxygen saturation in said blood based on the intensity variations of said wavelengths of light due to blood pulsations;
- and
- e. means for indicating said estimated values of said blood gas parameters.
A quantitative analysis instrument for noninvasive spectroscopic measurement of tissue pH in humans, said instrument comprising:
- a. a source of at least three different wavelengths of light, said wavelengths being in the range of 500 to 2500 nm;
- b. optics for directing said wavelengths of light into human tissue;
- c. at least one detector for measuring the intensities of at least a portion of said wavelengths of said light emerging from said tissue at, at least, three wavelengths of said light;
- d. electronics for processing said measured intensities to estimate tissue pH values;
- and
- e. means for indicating said estimated values of tissue pH.
A quantitative analysis instrument for noninvasive spectroscopic measurement of blood pH in human tissue, said instrument comprising:
- a. a source of at least three different wavelengths of light, said wavelengths being in the range of 500 to 2500 mm;
- b. optics for directing said wavelengths of light into said human tissue;
- c. at least one detector for measuring the intensity of at least a portion of said wavelengths of said light emerging from said human tissue at, at least, three wavelengths of said light;
- d. electronics for processing said measured intensities to estimate blood pH values in said blood;
- and
- e. means for indicating said estimated values of blood pH.
A quantitative analysis instrument for noninvasive spectroscopic measurement of arterial blood pH in tissue in a human, said instrument comprising:
- a. a source of at least three different wavelengths of light, said wavelengths being in the range of 500 to 2500 nm;
- b. optics for directing said wavelengths of light into tissue containing arterial blood;
- c. at least one detector for measuring the intensities of at least a portion of said wavelengths of said light emerging from said tissue at, at least, three wavelengths of said light during the systolic and diastolic portions of the cardiac cycle of said human;
- d. electronics for processing said measured intensities to estimate arterial blood pH values based on the intensity variations of said wavelengths of light due to blood pulsations;
- and
- e. means for indicating said estimated values of arterial blood pH.
A quantitative analysis instrument for noninvasive spectroscopic measurement of tissue [HCO.sub.3.sup.- ] in humans, said instrument comprising:
- a. a source of at least three different wavelengths of light, said wavelengths being in the range of 500 to 2500 nm;
- b. optics for directing said wavelengths of light into human tissue;
- c. at least one detector for measuring the intensities of at least a portion of said wavelengths of said light emerging from said tissue at, at least, three wavelengths of said light;
- d. electronics for processing said measured intensities to estimate tissue [HCO.sub.3.sup.- ] values;
- and
- e. means for indicating said estimated values of tissue [HCO.sub.3.sup.- ].
A quantitative analysis instrument for noninvasive spectroscopic measurement of blood [HCO.sub.3.sup.- ] in human tissue, said instrument comprising:
- a. a source of at least three different wavelengths of light, said wavelengths being in the range of 500 to 2500 nm;
- b. optics for directing said wavelengths of light into said tissue;
- c. at least one detector for measuring the intensities of at least a portion of said wavelengths of said light emerging from said tissue at, at least, three wavelengths of said light;
- d. electronics for processing said measured intensities to estimate blood [HCO.sub.3.sup.- ] values;
- and
- e. means for indicating said estimated values of blood [HCO.sub.3.sup.- ].
A quantitative analysis instrument for noninvasive spectroscopic measurement of arterial blood [HCO.sub.3.sup.- ] in tissue in a human, said instrument comprising:
- a. a source of at least three different wavelengths of light, said wavelengths being in the range of 500 to 2500 nm;
- b. optics for directing said wavelengths of light into tissue containing arterial blood;
- c. at least one detector for measuring the intensities of at least a portion of said wavelengths of said light emerging from said tissue at, at least, three wavelengths of said light during the systolic and diastolic portions of the cardiac cycle of said human;
- d. electronics for processing said measured intensities to estimate arterial blood [HCO.sub.3.sup.- ] values based on the intensity variations of said wavelengths of light due to blood pulsations;
- and
- e. means for indicating said estimated values of arterial blood [HCO.sub.3.sup.- ].
A quantitative analysis instrument for noninvasive spectroscopic measurement of tissue PCO.sub.2 in humans, said instrument comprising:
- a. a source of at least three different wavelengths of light, said wavelengths being in the range of 500 to 2500 nm;
- b. optics for directing said wavelengths of light into said human;
- c. at least one detector for measuring the intensities of at least a portion of said wavelengths of said light emerging from said tissue at, at least, three wavelengths of said light;
- d. electronics for processing said measured intensities to estimate tissue PCO.sub.2 values;
- and
- e. means for indicating said estimated values of tissue PCO.sub.2.
A quantitative analysis instrument for noninvasive spectroscopic measurement of blood PCO.sub.2 in human tissue, said instrument comprising:
- a. a source of at least three different wavelengths of light, said wavelengths being in the range of 500 to 2500 nm;
- b. optics for directing said wavelengths of light into said tissue;
- c. at least one detector for measuring the intensities of at least a portion of said wavelengths of said light emerging from said tissue at, at least, three wavelengths of said light;
- d. electronics for processing said measured intensities to estimate blood PCO.sub.2 values;
- and
- e. means for indicating said estimated values of blood PCO.sub.2.
A quantitative analysis instrument for noninvasive spectroscopic measurement of arterial blood PCO.sub.2 in tissue in a human, said instrument comprising:
- a. a source of at least three different wavelengths of light, said wavelengths being in the range of 500 to 2500 nm;
- b. optics for directing said wavelengths of light into tissue containing arterial blood;
- c. at least one detector for measuring the intensities of at least a portion of said wavelengths of said light emerging from said tissue at, at least, three wavelengths of said light during the systolic and diastolic portions of the cardiac cycle of said human;
- d. electronics for processing said measured intensities to estimate arterial blood PCO.sub.2 values based on the intensity variations of said wavelengths of light due to blood pulsations;
- and
- e. means for indicating said estimated values of arterial blood PCO.sub.2.
A method of determining noninvasively at least one of pH, [HCO.sub.3.sup.- ], PCO.sub.2 in a human, said method comprising steps of:
- a. generating light at three or more different wavelengths, said wavelengths being in the range of 500 nm to 2500 nm;
- b. noninvasively irradiating blood containing tissue with said wavelengths so that there is differential attenuation of at least some intensities of said wavelengths, said wavelength dependent differential attenuation being a function of said blood containing tissue and the unknown value of at least one of pH, [HCO.sub.3.sup.- ], and PCO.sub.2 in said blood containing tissue;
- c. measuring said intensities of said wavelengths emerging from said blood containing tissue to obtain a set of at least three spectral intensities v. wavelengths;
- and
- d. estimating said value of said at least one of pH, [HCO.sub.3.sup.- ], and PCO.sub.2, from said intensities emerging from said blood containing tissue, said value being within the physiological ranges observed in blood containing tissue.
Dependencies are inferred from the claim text.