Non-invasive measurement of blood oxygen saturation

A method for non-invasive determination of oxygen saturation of blood within a deep vascular structure of a human or animal patient comprising locating within the external auditory canal of the patient in a vicinity of the internal jugular vein and/or sigmoid sinus emitter and receiver elements of a light oximeter device, wherein optimal location of said elements is achieved through matching of a plethysmography trace obtained from the oximeter device to known plethysmography characteristics of the internal jugular vein and/or sigmoid sinus, wherein oxygen saturation is determined from a ratio of light absorbed at different wavelengths by haemoglobin in blood within the internal jugular vein and/or sigmoid sinus.

A method for non-invasive determination of oxygen saturation of blood within a deep vascular structure of a human or animal patient comprising locating within the external auditory canal of the patient in a vicinity of the internal jugular vein emitter and receiver elements of a light oximeter device, wherein optimal location of said elements is achieved through matching of a plethysmography trace obtained from the oximeter device to known plethysmography characteristics of the internal jugular vein, wherein the emitter element emits light at wavelengths of from about 1045 nm to about 1055 nm and from about 1085 nm to about 1095 nm, and wherein oxygen saturation is determined from a ratio of light absorbed at these two wavelengths by haemoglobin in blood within the internal jugular vein.

An oximetry device comprising a central processing unit, a display and emitter and receiver elements adapted for releasable application to human or animal skin, all of which are workably connected in use;

• the emitter element is equipped to emit light of wavelengths of both from about 1045 nm to about 1055 nm and from about 1085 nm to about 1095 nm and the receiver element is adapted to detect said light, with information relating to levels of emitted and received light being transmitted to said central processing unit;
• said central processing unit being capable of matching plethysmography characteristics derived from the information relating to levels of emitted and received light with known plethysmography characteristics of a deep vascular structure of interest, to ensure optimal location in use of the emitter and receiver elements on the skin in a vicinity of the deep vascular structure of interest;
• said central processing unit also being capable of deriving from the information relating to levels of emitted and received light a measurement of blood oxygen saturation within the deep vascular structure of interest, which can be made available on the display.