METHOD AND DEVICE FOR MEASURING PARAMETERS OF CARDIAC FUNCTION

• US 20090326352A1
• Filed: 02/13/2008
• Published: 12/31/2009
• Est. Priority Date: 02/16/2007
• Status: Active Grant

• Current Assignee: Mespere LifeSciences Inc.
• Original Assignee: Mespere LifeSciences Inc.
• Inventors: Cheng, Xuefeng
• Granted Patent: US 8,417,306 B2
• Time in Patent Office: Days
• US Class Current: 600/324
• CPC Class Codes: A61B 2562/0233 Special features of optical sensors or probes classified in A61B5/00
• CPC Class Codes: A61B 2562/043 in a linear array
• CPC Class Codes: A61B 2562/046 in a matrix array
• 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 5/021 Measuring pressure in heart or blood vessels A61B5/0205 takes precedence
• CPC Class Codes: A61B 5/02116 of pulse wave amplitude A61B5/02225 takes precedence
• 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 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/14552 Details of sensors specially adapted therefor
• CPC Class Codes: A61B 5/4884 inducing physiological or psychological stress, e.g. applications for stress testing
• CPC Class Codes: A61B 5/6833 Adhesive patches

Abstract

A device for non-invasively measuring at least one parameter of a cardiac blood vessel in a patient is provided. The device comprises at least one light source that emits light in the 400 nm to 1000 nm wavelength range; at least one photodetector adapted to receive light emitted by the light source and generate an output based on the received light, wherein said light is reflected from or transmitted through tissue of the patient, the output of said photodetector being correlated with a parameter of the blood vessel; and at least one probe for facilitating delivery of light from the light source to an external tissue site on the patient in the proximity of the cardiac blood vessel and receipt of light by the photodetector. A system and methods of monitoring/measuring cardiac parameters utilizing the device and/or system are also provided.

Claims

1. A device for non-invasively measuring at least one parameter of a cardiac blood vessel in a patient comprising:

at least one light source that emits light in the 400 nm to 1000 nm wavelength range;

at least one photodetector adapted to receive light emitted by the light source and generate an output based on the received light, wherein said light is reflected from or transmitted through tissue of the patient, the output of said photodetector being correlated with a parameter of the blood vessel; and

at least one probe for facilitating delivery of light from the light source to an external tissue site on the patient in the proximity of the cardiac blood vessel and receipt of light by the photodetector.

2. A device as defined in claim 1, additionally comprising a signal-processing device in communication with the photodetector, said signal-processing device adapted to translate light received from the photodetector into a visual output.

3. A device as defined in claim 2, wherein said visual output is a time-varying waveform.

4. A device as defined in claim 1, adapted to emit and receive light of at least two different wavelengths in the 400 nm to 1000 nm wavelength range.

5. A device as defined in claim 1, comprising at least two photodetectors, each of said photodetectors adapted to receive light at a distinct wavelength.

6. A device as defined in claim 1, wherein said light source and said photodetector are embedded in said probe.

7. A device as defined in claim 1, wherein transmitting optical fibres transmit light from said light source to said probe.

8. A device as defined in claim 1, wherein receiving optical fibres receive reflected light from said probe.

9. A device as defined in claim 1, comprising a plurality of light sources and a plurality of-photodetectors, wherein each light source emits light that is received by a corresponding photodetector.

10. A device as defined in claim 4, wherein said light source is adapted to emit light at more than one wavelength.

11. A device as defined in claim 4, comprising at least a first and second light source each of which emit light at a different wavelength, and at least a first and second photodetector, wherein said first photodetector is adapted to receive light from said first light source and said second photodetector is adapted to receive light from said second light source.

12. A device as defined in claim 1, comprising a plurality of probes, wherein each probe comprises at least one light source and at least one photodetector.

13. A device useful to monitor a parameter of a cardiac blood vessel in a patient comprising:

at least one light-emitting component adapted to emit light in the 400 nm to 1000 nm wavelength range;

at least one light-receiving component adapted to receive light emitted by the light-emitting component and translate said light into a recordable output, wherein said light is reflected from or transmitted through tissue of the patient; and

at least one probe which facilitates delivery of light from the light-emitting component to an external tissue site on the patient in the proximity of a cardiac blood vessel and receipt of light reflected from or transmitted through said patient site by the light-receiving component.

14. A device as defined in claim 13, wherein the output from said light-receiving component is current.

15. A device as defined in claim 13, wherein said light-emitting component is a light source that is set in the probe.

16. A device as defined in claim 13, wherein said light-receiving component is a photodetector that is set in the probe.

17. A device as defined in claim 13, wherein said light-emitting component comprises a light source and light-transmitting optical fibres, wherein said fibres are set in the probe.

18. A device as defined in claim 13, wherein said light-receiving component comprises a photodetector and light-receiving optical fibres, wherein said fibres are set in the probe.

19. A system useful to monitor a parameter of a cardiac blood vessel in a patient comprising:

at least one light-emitting component adapted to emit light in the 400 nm to 1000 nm wavelength range;

at least one light-receiving component adapted to receive light emitted by the light-emitting component and translate said light into a recordable output, wherein said light is reflected from or transmitted through tissue of the patient; and

at least one probe which facilitates delivery of light from the light-emitting component to an external tissue site on the patient in the proximity of a cardiac blood vessel and receipt of light reflected from or transmitted through said patient site by the light-receiving component; and

a signal-processing device adapted to translate the output from said light-receiving component to a visual form.

20. A system as define in claim 19, wherein said signal-processing device comprises a microprocessor and a display unit.

21. A method for determining a parameter of a cardiac blood vessel in a patient comprising the steps of:

directing a beam of light having a wavelength in the range of 400 nm to 1000 nm to an external tissue site on the patient that is in the proximity of the blood vessel;

detecting light reflected from the tissue site or transmitted through the tissue site;

translating the detected light into an output signal against time; and

calculating the parameter of the blood vessel using the output signal.

22. A method as defined in claim 21, wherein the parameter is selected from the group consisting of blood vessel pulse, blood vessel volume, blood vessel oxygenation, blood vessel flow, blood vessel pressure and blood vessel content.

23. A method as defined in claim 21, wherein the cardiac blood vessel is selected from the group consisting of the internal jugular vein, the external jugular vein and the carotid artery.

24. A method as defined in claim 21, wherein the output signal is current or voltage.

25. A method as defined in claim 21, wherein the output signal is translated into a time-varying visual output.

26. A method as defined in claim 25, wherein the time-varying visual output is a waveform.

27. A method as defined in claim 21, comprising directing more than one beam of light at the same or different tissue site on a patient, each beam having a different wavelength in the range of 400 nm to 1000 nm.

28. A method as defined in claim 27, wherein the parameter is blood content calculated according to modified Beer Lambert'"'"'s law.

29. A method as define in claim 27, wherein the parameter is blood oxygenation calculated according to modified Beer Lambert'"'"'s law.

30. A method as defined in claim 27, wherein the light of each wavelength is detected to generate an output signal for two different blood vessels.

31. A method for measuring the blood content of a chromophore in a patient comprising:

directing a light beam having at least first and second selected wavelengths at an external tissue site on the patient that is in the proximity of a cardiac blood vessel, wherein said selected wavelengths are based on the absorption characteristics of the chromophore;

detecting light reflected from the tissue or transmitted through the tissue at the selected wavelengths; and

translating the detected light into an output current in order to determine the blood content of said chromophore according to modified Beer Lambert'"'"'s law.

32. A method of determining blood oxygenation of a cardiac vessel in a patient comprising:

directing a first light beam having a first wavelength of 780 nm and a second light beam having a second wavelength of 850 nm at an external tissue site on the patient that is in the proximity of a cardiac blood vessel;

detecting light reflected from the tissue or transmitted through the tissue at the first and second wavelengths; and

translating the detected light into an output current for the first and second wavelengths in order to calculate the blood oxygenation of the cardiac vessel according to modified Beer Lambert'"'"'s law.

33. A method of determining cardiac output in a patient comprising;

calculating the blood oxygenation of the internal jugular vein as defined in claim 32;

calculating the blood oxygenation of the carotid artery as defined in claim 32; and

calculating the cardiac output according to Fick'"'"'s law using the calculated blood oxygenation of the internal jugular vein blood and the carotid artery.

34. A method of determining central venous pressure in a patient comprising:

directing a beam of light having a wavelength in the range of 400 nm to 1000 nm at a series of external tissue sites on the patient along the jugular vein starting from the sternal angle;

detecting light reflected from the tissue site or transmitted through each tissue site;

translating the detected light into an output signal against time to determine the highest position along the vein to yield a signal (d); and

calculating the central venous pressure (P) according to the equation P=(d+5)sin 9, wherein 9 is the inclined body angle from horizontal of the patient.