Abstract: A spectrophotometric method and apparatus for determining the degree of oxygen saturation of the hemoglobin in the blood within a body part utilizes differences in light absorption based on differences in extinction coefficients at different wavelengths. Oxygen saturation is determined by utilizing absorption at three or more wavelengths of radiation preferably in the near red and infrared region (NIR) of the spectrum, specifically tailored to two or more components to be detected by the radiation. The first (reference) wavelength is preferably chosen to be at an isosbestic point for the two components, commonly the oxygenated and deoxygenated forms of hemoglobin. The absorption at the isosbestic point is subtracted from the absorption at the other wavelengths. Using these differences in absorption, the amount of each of the components encountered by the light may be determined without determination of pathlength, which would be required to determine the concentration.

Abstract: A spectrophotometric method is described of quantitatively determining the concentration of a dilute component in either a clear or a strongly light-scattering environment containing same in unknown concentration together with a reference component of known concentration, by a series of contemporaneous radiation-directing and measurement steps of radiation of selected varying wavelengths. Specific applications are disclosed involving the in situ, in vivo, non-invasive spectrophotometric determination of blood-borne as well as tissue species, e.g., hemoglobin, and oxyhemoglobin, and intra-cellular enzyme cytochrome c oxidase, in human body parts such as fingers, hands, toes, feet, earlobes, etc., as well as organs such as the brain, skeletal muscle, liver, etc.

Abstract: Means are provided for securing to the human body a light source housing and a light detector housing used for monitoring metabolism, said means comprising sockets adapted to fit over the housings and having tab members adapted to be adhesively secured to the body to maintain the respective light source and light detector housings in spaced relation on the body and further comprising a light-shielded pad fitted over said sockets and adhered to the body to provide light shielding for the light source and light detector confined in said housings.

Abstract: A mounting structure secures to a selected portion of the human body, e.g., the head, a limb, or the torso, and incorporates light source and light detecting means adapted for association with spectrophotometric circuitry for in situ, in vivo monitoring of local metabolism in the area of the body where the structure is secured.

Abstract: A mounting structure secures to a selected portion of the human body, e.g., the head, a limb, or the torso, and incorporates light source and light detecting means adapted for association with spectrophotometric circuitry for in situ, in vivo monitoring of local metabolism in the area of the body where the structure is secured.

Abstract: A spectrophotometric transillumination method and apparatus are directed to non-invasive, continuous, atraumatic, in vivo, in situ monitoring of metabolism in a body organ. In the described applications, measuring and reference wavelengths within the near infrared region, i.e., 700-1300 nm, are utilized for non-invasive, continuous, atraumatic, in situ, in vivo monitoring of oxidative metabolism by monitoring oxygen sufficiency in an internal organ, e.g., the brain or heart, of a human or animal body. Advantage is taken of the critical characteristic of cellular enzyme cytochrome a, a.sub.3 within the optical path and within the radiated portion of the selected organ for absorbing the selected measuring wavelength and for light of this measuring wavelength, as well as at least one reference wavelength within the same defined infrared region and at a low, non-hazardous level of intensity to travel through and be detectable at the end of a relatively long path, e.g.

Abstract: A spectrophotometric method, apparatus and reflectance technique is directed to non-invasive, harmless, continuous, atraumatic, in vivo, in situ monitoring of metabolism in a body organ utilizing measuring and reference wavelengths within the near infrared region, i.e., 700-1300 nm. Monitoring of oxidative metabolism is accomplished by monitoring oxygen sufficiency in an organ, normally an internal vital organ, e.g., the brain or heart, of a living human or animal body. Advantage is taken of the critical characteristic of cellular enzyme cytochrome a, a.sub.