System and method for monitoring arterial and venous blood oxygen, blood glucose, and blood constituent concentration

A method for determining oximetry relationship based upon red-light and infra-red light plethysmography waveforms, which are representative of arterial pulse signals, measured by any of optical absorption or transmission, comprising the steps of:

• utilizing system identification to produce a state-space linear model to define a transfer function relationship between a full arterial pulse waveform, defined as the arterial pulse signal without the effect of atrial diastolic blood flow demand, as an input or output in the red-light plethysmography waveform and a full arterial pulse waveform as an output or input, respectively, measured in the infra-red light plethysmography waveform for creating an arterial pulse oxygen saturation model;
• using the arterial pulse oxygen saturation model to determine arterial oxygen saturation as a function of the model's characteristic parameters or coefficients;
• utilizing system identification to produce a state-space linear model to define a transfer function relationship between an arterio-venous pulse waveform, defined by subtraction of the arterial pulse waveform from the full arterial pulse waveform, as an input or output in the red-light plethysmography waveform and an arterio-venous pulse waveform as an output or input, respectively, measured in the infra-red light plethysmography waveform for creating a venous pulse oxygen saturation model;
• and
• using the venous pulse oxygen saturation model to determine venous oxygen saturation as a function of the model's characteristic parameters or coefficients;

A method for determining transfer function relationships based upon at least two light plethysmography waveforms, between infrared to ultra-violet light wavelength range, which are representative of arterial pulse signals, measured by any of optical absorption or transmission methods, comprising the steps of:

• utilizing system identification to produce a state-space linear model to define at least one transfer function relationship between a full arterial pulse waveform, defined as the arterial pulse signal without the effect of atrial diastolic blood flow demand, as an input or output plethysmography waveform, measured at a first light wavelength, and a full arterial pulse waveform, as an output or input plethysmography waveform, respectively, measured at a second light wavelength for creating an arterial pulse blood constituent concentration model;
• using said arterial pulse blood constituent concentration model to determine arterial blood constituent concentration as a function of model's characteristic parameters or coefficients;
• utilizing system identification to produce a state-space linear model to define a transfer function relationship between an arterio-venous pulse waveform, defined by subtraction of the arterial pulse waveform from the full arterial pulse waveform, as an input or output at a first wavelength light plethysmography waveform and an arterio-venous pulse waveform as an output or input, respectively, measured at a second wavelength light plethysmography waveform for creating a venous pulse blood constituent concentration model;
• and
• using said venous pulse blood constituent concentration model to determine venous blood constituent concentration as a function of model's characteristic parameters or coefficients;