Nippon Colin Co., Ltd.

Colin Electronics Co., Ltd.

Reuben W Edgar

Ronald L Branstetter

Dennis W Gilstad

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.

System for correction of trends associated with pulse wave forms in

A noninvasive optical oximeter for measuring oxygen saturation of arterial blood. A sample of blood is illuminated with light at four different wavelengths. Light reflected by the blood is sensed by a photodetector and a plurality of output signals are created in response thereto. The reflected light at each of the four wavelengths is detected after contact with the blood and is correlated with the oxygen saturation of the patient's blood using mathematical relationships for arterial and venous oxygen saturation. The present invention provides a noninvasive backscatter oximeter which is capable of providing accurate indications of a patient's blood oxygen saturation without the need for obtaining prior information relating to the oxygen content of the patient's blood.

Backscatter oximeter

A noninvasive optical oximeter for measuring oxygen saturation of arterial blood. A sample of blood is illuminated with light at two different wavelengths. Light reflected by the blood is sensed by a photodetector and an output signal is created in response thereto. The output signal is processed to form a quotient representing the AC components of the reflected light at each wavelength. The oxygen saturation of the blood is calculated by correlating this quotient with an oxygen saturation reference curve uniquely representative of the blood oxygen saturation characteristics of a particular individual. The reference curve used in the preferred embodiment of the invention is calibrated in a two-step process which minimizes the effects of calibration errors. A first oxygen saturation reference curve is calculated which is based on a linear relationship between the ratio of the AC components of the reflected light. This curve is then used to calibrate a second reference curve based on a linear ratio of the squared values of the AC components of the reflected light. Once the second reference curve has been properly calibrated, it is used for all subsequent measurements of oxygen saturation.

Noninvasive reflectance oximeter

A noninvasive optical oximeter for measuring oxygen saturation of arterial blood. A sample of blood is illuminated with light at two different wavelengths. Light reflected by the blood is sensed by a photodetector and an output signal is created in response thereto. The output signal is processed to form a quotient representing the AC components of the reflected light at each wavelength. The oxygen saturation of the blood is calculated by correlating this quotient with an oxygen saturation reference curve uniquely representative of the blood oxygen saturation characteristics of a particular individual.

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San Antonio, TX, United States of America

Reuben W Edgar