SYSTEM AND METHOD FOR MONITORING ARTERIAL AND VENOUS BLOOD OXYGEN, BLOOD GLUCOSE, AND BLOOD CONSTITUENT CONCENTRATION

• US 20150031969A1
• Filed: 07/24/2013
• Published: 01/29/2015
• Est. Priority Date: 09/14/2012
• Status: Active Grant

• Current Assignee: Mohammad Khair
• Original Assignee: Mohammad Khair
• Inventors: Khair, Mohammad
• Granted Patent: US 9,451,920 B2
• Time in Patent Office: Days
• US Class Current: 600/316
• CPC Class Codes: A61B 5/02028 Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction
• CPC Class Codes: A61B 5/0205 Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
• CPC Class Codes: A61B 5/02055 Simultaneously evaluating both cardiovascular condition and temperature
• CPC Class Codes: A61B 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/02108 from analysis of pulse wave characteristics
• CPC Class Codes: A61B 5/0215 by means inserted into the body catheters A61M25/00
• CPC Class Codes: A61B 5/02433 for infrared radiation
• CPC Class Codes: A61B 5/026 Measuring blood flow A61B3/1233, A61B3/1241 take precedence
• CPC Class Codes: A61B 5/0261 using optical means, e.g. infrared light
• CPC Class Codes: A61B 5/029 Measuring or recording blood output from the heart, e.g. minute volume A61B8/065 takes precedence
• CPC Class Codes: A61B 5/0295 using plethysmography, i.e. measuring the variations in the volume of a body part as modified by the circulation of blood therethrough, e.g. impedance plethysmography
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 takes precedence
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/7225 Details of analog processing, e.g. isolation amplifier, gain or sensitivity adjustment, filtering, baseline or drift compensation A61B5/30, A61B5/316 take precedence; transformers for specific applications H01F38/00; amplifiers H03F
• CPC Class Codes: A61B 5/7239 using differentiation including higher order derivatives
• CPC Class Codes: A61B 5/7257 using Fourier transforms
• CPC Class Codes: A61B 5/726 : using Wavelet transforms
• CPC Class Codes: A61B 5/742 : using visual displays A61B5/339 takes precedence
• CPC Class Codes: A61B 5/7475 : User input or interface means, e.g. keyboard, pointing device, joystick
• CPC Class Codes: A61M 1/14 : Dialysis systems; Artificial kidneys; Blood oxygenators semi-permeable membranes characterised by the material, manufacturing processes therefor B01D71/00 ; Reciprocating systems for treatment of body fluids, e.g. single needle systems for hemofiltration or pheresis
• CPC Class Codes: A61M 16/01 : specially adapted for anaesthetising A61M16/104, A61M16/18 take precedence
• CPC Class Codes: A61M 2205/33 : Controlling, regulating or measuring
• CPC Class Codes: A61M 2205/3303 : Using a biosensor
• CPC Class Codes: A61M 2205/3334 : Measuring or controlling the flow rate
• CPC Class Codes: A61M 2230/005 : Parameter used as control input for the apparatus
• CPC Class Codes: A61M 2230/42 : Rate
• CPC Class Codes: A61M 5/1723 : using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00
• CPC Class Codes: A61M 60/113 : in other functional devices, e.g. dialysers or heart-lung machines
• CPC Class Codes: A61M 60/126 : implantable via, into, inside, in line, branching on, or around a blood vessel
• CPC Class Codes: A61M 60/148 : in line with a blood vessel using resection or like techniques, e.g. permanent endovascular heart assist devices
• CPC Class Codes: A61M 60/178 : drawing blood from a ventricle and returning the blood to the arterial system via a cannula external to the ventricle, e.g. left or right ventricular assist devices
• CPC Class Codes: A61M 60/37 : Haemodialysis, haemofiltration or diafiltration
• CPC Class Codes: A61M 60/515 : Regulation using real-time patient data
• CPC Class Codes: A61M 60/523 : using blood flow data, e.g. from blood flow transducers
• CPC Class Codes: A61M 60/531 : using blood pressure data, e.g. from blood pressure sensors
• CPC Class Codes: A61M 60/585 : User interfaces
• CPC Class Codes: A61N 1/36585 : controlled by two or more physical parameters
• CPC Class Codes: A61N 1/3987 : characterised by the timing or triggering of the shock

Abstract

A system for measuring of arterial and venous blood constituent concentration based first on measuring cardiac blood flow balance parameter between the right chamber of the heart and the left chamber of the heart, which includes a sensor device for measuring one of blood pressure and blood flow rate and blood constituent concentration of a patient so as to generate an arterial pulse signal. A processing unit is responsive to the arterial pulse signal for generating full arterial pulse plethysmography waveforms, arterio-venous pulse plethysmography waveforms, and balance parameters. A computational device that is responsive to plethysmography waveforms generating a plurality of state space linear transfer functions by applying system identification between plethysmography waveforms at various wavelengths representing a plurality of models of the blood constituent concentration, including oxygen, carbon dioxide, hemoglobin, and glucose, and displaying related useful information.

Claims

1. A method for determining arterial and venous side oximetry based upon full arterial pressure pulse waveform and arterio-venous pressure pulse waveform, comprising the steps of:

measuring of plethysmography waveforms of red and infra-red lights which are representative of arterial pulses measured by any of optical absorption or transmission;

determining a full arterial pulse waveform, defined as the arterial pulse signal without the effect of atrial diastolic blood flow demand, and an arterio-venous pulse waveform, defined by subtracting the arterial pulse signal from the full arterial pulse waveform, for each of the red and infra-red light plethysmography waveforms;

determining an arterial side and a venous side normalized pulse variable component to pulse constant component for each of the red and infra-red light plethysmography waveforms by using the full arterial pulse waveform for the arterial side and the arterio-venous pulse waveform for the venous side;

determining an arterial side and a venous side normalized ratio of pulse variable component to pulse constant component for each of the red and infra-red light plethysmography waveforms by using the full arterial pulse waveform for the arterial side and the arterio-venous pulse waveform for the venous side;

determining the arterial oxygen saturation as a function of a first ratio of the normalized ratio of the full arterial pulse variable component to the full arterial pulse constant component for the arterial side for the red light plethysmography waveform to the normalized ratio of the full arterial pulse variable component to the full arterial pulse constant component for the arterial side for the infra-red light plethysmography waveform;

determining the venous oxygen saturation as a function of a second ratio of the normalized ratio of the arterio-venous pulse variable component to the arterio-venous pulse constant component for the venous side for the red light plethysmography waveform to the normalized ratio of the arterio-venous pulse variable component to the arterio-venous pulse constant component for the venous side for the infra-red light plethysmography waveform; and

optionally calculating arterial and venous oxygen content using Fick'"'"'s equation.

2. A method for determining arterial and venous side oximetry as claimed in claim 1, further including the step of calculating of one of Left-Right balance parameter, defined by said arterial pulse measured at one of an aorta and one of its arterial branches, and Right-Left balance parameter, defined by said arterial pulse measured at one of a pulmonary artery and one of its arterial branches, for each of the red and infra-red light plethysmography waveforms.

3. A method for determining arterial and venous side oximetry as claimed in claim 2, wherein the Left-Right balance parameter for the red light per cardiac cycle is defined by the equation LRB_red=AV_red/FAP_red, where AV_red is the integral of the arterio-venous pulse waveform and FAP_red is the integral of the full arterial pulse waveform for the red light plethysmography waveform of the aorta or any of its arterial branches.

4. A method for determining arterial and venous side oximetry as claimed in claim 2, wherein the Left-Right balance parameter for the infra-red light per cardiac cycle is defined by the equation LRB_ir=AV_ir/FAP_ir, where AV_ir is the integral of the arterio-venous pulse waveform and FAP_ir is the integral of the full arterial pulse waveform for the infra-red light plethysmography waveform of the aorta or any of its arterial branches.

5. A method for determining arterial and venous side oximetry as claimed in claim 2, wherein the Right-Left balance parameter for the red light per cardiac cycle is defined by the equation RLB_red=AV_red/FAP_red, where AV_red is the integral of the arterio-venous pulse waveform and FAP_red is the integral of the full arterial pulse waveform for the red light plethysmography waveform of the pulmonary artery or any of its arterial branches.

6. A method for determining arterial and venous side oximetry as claimed in claim 2, wherein the Right-Left balance parameter for the red light per cardiac cycle is defined by the equation RLB_ir=AV_ir/FAP_ir, where AV_ir is the integral of the arterio-venous pulse waveform and FAP_ir is the integral of the full arterial pulse waveform for the red light plethysmography waveform of the pulmonary artery or any of its arterial branches.

7. 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;

8. 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;

9. The method for determining transfer function claim in claim 8, wherein the blood constituent concentration is one of oxygen, carbon dioxide, glucose, and hemoglobin.

10. The method for determining transfer function claim in claim 8, wherein the said full arterial pulse at any said wavelength is estimated as an output of a transfer function, defined by system identification, using as input the full arterial pulse of a measured arterial pulse at the same wavelength.

11. The method for determining transfer function claim in claim 8, wherein the said arterio-venous pulse at any said wavelength is estimated as an output of a transfer function, defined by system identification, using as input the arterio-venous pulse of a measured arterial pulse at the same wavelength.

12. The method for determining transfer function claim in claim 8, further comprising the steps of providing a processor unit and configuring the processor unit to perform all said processing steps.

13. The method for determining transfer function claim in claim 12, wherein said processor unit is comprised of microprocessor.

14. 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 an arterial pulse waveform, as an input or output plethysmography waveform, measured at a first light wavelength, and an 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;

15. The method for determining transfer function claim in claim 14, wherein the blood constituent concentration is one of oxygen, carbon dioxide, glucose, and hemoglobin.