US 5,216,598 A · System for correction of trends associated with pulse wave forms in oximeters

Abstract

A noninvasive optical oximeter measures oxygen saturation of arterial blood. A patient's arterial blood is illuminated with light at two different wavelengths and the intensity of the reflected light is sensed by a photodetector and an output signal is created in response thereto. The output signal is processed to form a ratio representing the AC component of the reflected light at each wavelength over the DC component. The oxygen saturation of the blood is calculated by correlating the quotient of these ratios with an oxygen reference curve uniquely representative of the blood oxygen characteristics of a particular patient. The pulse amplitude signals for the AC component at each wavelength are compensated for the effects of upward or downward trends and, therefore, the accuracy of the blood oxygen saturation calculation is significantly increased.

Claims16

Dependent claims

An oximeter for measuring the oxygen saturation of blood comprising:

first and second sources of electromagnetic radiation having first and second wavelengths of radiation, respectively, for illuminating a sample of said blood;
a sensor for detecting electromagnetic radiation generated by said first and second sources which has illuminated said blood sample and for producing electrical signals corresponding to the intensity of the detected electromagnetic radiation at each of said first and second wavelengths, each of radiation at each of said first and second wavelengths, each of said electrical signals having an AC pulsatile component and a DC component;
a signal correction circuit for modifying said AC pulsatile component of each of said electrical signals to remove upward and downward trend effects therefrom;
a signal processor for combining said modified AC pulsatile components and said DC components of said electrical signals for producing a measurement signal related to the oxygen saturation of said blood sample.

1 more element

Signal generating and conditioning apparatus for use in measurement of the oxygen saturation of arterial blood in tissue, said apparatus comprising:

first and second sources of electromagnetic radiation having first and second wavelengths of radiation, respectively, for illuminating a sample of said blood;
a sensor for detecting electromagnetic radiation generated by said first and second sources which has illuminated said blood sample and for producing electrical signals corresponding to the intensity of the detected electromagnetic radiation at each of said first and second wavelengths, each of said electrical signals having an AC pulsatile component and a DC component;
and
a signal correction circuit for modifying said AC pulsatile component of each of said electrical signals to remove upward and downward trend effects therefrom.

1 more element

Dependencies are inferred from the claim text.

System for correction of trends associated with pulse wave forms in oximeters

Life of this patent

System for correction of trends associated with pulse wave forms in oximeters

Life of this patent

Abstract

Claims16