Method for spectrophotometric blood oxygenation monitoring

An apparatus for non-invasively determining a blood oxygen parameter value of a subject's tissue, comprising:

• at least one transducer having at least one light source and at least one light detector, wherein the transducer is configured to be applied to a tissue surface of the subject with the at least one light source positioned to transmit light into the subject's tissue and the at least one light detector positioned to sense the transmitted light after passage through the subject's tissue;
• and
• a processor portion having at least one processor in communication with a memory device storing algorithmic instructions, which instructions cause the at least one processor to selectively:
• control the at least one light source to transmit light at one or more wavelengths of red light into the subject's tissue;
• control the at least one light detector to sense the transmitted red light after passage through the subject's tissue and produce initial signals representative of the sensed red light;
• receive and process the initial signals from the at least one light detector and produce first signal data from the initial signals;
• alter the algorithmic instructions using the first signal data to account for the specific physical characteristics of the particular subject's tissue being sensed;
• and
• determine the blood oxygen parameter value within the subject's tissue using the selectively altered algorithmic instructions.