Portable metabolic analyzer system

• US 10,078,074 B2
• Filed: 01/21/2014
• Issued: 09/18/2018
• Est. Priority Date: 01/22/2013
• Status: Active Grant

• Current Assignee: Arizona Board of Regents (University of Arizona)
• Original Assignee: Arizona Board of Regents (University of Arizona)
• Inventors: Tsow, Francis, Xian, Xiaojun, Forzani, Erica, Tao, Nongjian
• Primary Examiner(s): Natnithithadha, Navin
• Application Number:
  US14/761,732
• Publication Number:
  US 20150369795A1
• Time in Patent Office: 1,701 Days
• Field of Search: 600529-543
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/083 Measuring rate of metabolism by using breath test, e.g. measuring rate of oxygen consumption
• CPC Class Codes: A61B 5/087 Measuring breath flow
• CPC Class Codes: A61B 5/375 using biofeedback
• CPC Class Codes: A61B 5/7405 using sound
• CPC Class Codes: G01N 33/497 of gaseous biological material, e.g. breath

Abstract

A system for measuring and tracking metabolic rate, physical activity and calorie intake. The metabolic rate is measured with a design that features an adaptive sampling mechanism for accurate breath sample collection, optimized flow rate measurement for minimizing backpressure while maximizing accuracy, humidity regulation and water condensation reduction mechanism for reliable performance, as well as breath temperature measurement for volume and humidity corrections. The system further comprises an improved algorithm for determining physical activity such as related energy expenditure, and a mechanism for tracking changes in food intake over time.

Claims

1. A system for measuring and tracking metabolic rate comprising:

a mouthpiece having an inlet for the introduction of exhaled breath into a flow path;

wherein the mouthpiece includes at least one orifice with a cross sectional area in the range of 4 mm² to 40 mm² in the flow path, and where the orifice is at least 50% smaller than the inlet cross sectional area;

a colorimetric sensor providing a first output signal representing chemical measurements;

a differential pressure sensor with a sensor inlet located on the inlet side of the orifice, where the differential pressure sensor provides a second output signal representing pressure measurements; and

an adaptive sampling mechanism to detect and learn the user'"'"'s natural breathing pattern to assist the user to perform consistent measurement, and to determine resting energy expenditure from pressure and chemical measurements, with pre-determined calibration curves that relate the first output signal representing chemical measurements to the chemical concentrations and the second output signal representing pressure measurements.

2. The system of claim 1 wherein the adaptive sampling mechanism

resides in a processor, where the processor is adapted to play audio with a rhythm and volume, or video with motion sequence, where the rhythm and volume or motion sequence is adjusted to the pre-determined natural breathing pattern.

3. The system of claim 2 wherein the adaptive sampling mechanism further operates

to detect changes in the breathing pattern over time;

to memorize changes in the breathing pattern over time; and

to adjust the audio rhythm and volume or video motion sequence according to the changes in the breathing.

4. The system of claim 2 wherein the adaptive sampling mechanism further operates

to detect breathing patterns;

and

to memorize breathing patterns.

5. The system of claim 2 wherein the adaptive sampling mechanism further operates

to detect breathing patterns;

to memorize breathing patterns;

to detect time intervals in which the breathing pattern is regular; and

to determine volume flow rate based on the data acquired during the time intervals.

6. The system of claim 1 wherein the sensor inlet is located at least 1 mm away from the orifice.

7. The system of claim 1 wherein the differential pressure sensor is mounted with an orientation at which the pressure reading is least dependent on earth gravity.

8. The system of claim 1 wherein the adaptive sampling mechanism operates to determine the resting energy expenditure curve with the Weir equation using at least measured exhaled volume flow rate.

9. The system of claim 1 further comprising a fan connected to the flow path to dry out water from condensation in the apparatus.

10. The system of claim 9 wherein the fan is connected to the flow path via a one way valve.

11. The system of claim 1 wherein the flow path comprises a detection chamber where at least one gas component in the exhaled breath is detected.

12. The system of claim 11 wherein the detection chamber comprises:

at least one light emitting diode;

at least one photodiode detector;

a colorimetric sensor cartridge holder; and

a colorimetric sensor cartridge inserted into the sensor cartridge holder.

13. The system of claim 12 wherein the colorimetric sensor cartridge comprises:

a solid surface;

a patterned structure in at least one area of the solid surface;

sensing chemicals coated onto the area;

a reference area for signal correction; and

a notch design for positioning.

14. The system of claim 13 wherein the patterned structure comprises at least 81 vertices, and a depth between 20 μ

m and 200 μ

m.

15. The system of claim 12 wherein the distance between the top surface of the sensor cartridge and the top surface of the photo diode detector is less than 5 mm.

16. The system of claim 11 wherein a fan is attached to the detection chamber via a one-way valve.

17. The system of claim 1 further comprising a filter positioned between a user'"'"'s mouth and the inlet of the flow path to prevent saliva of from entering the flow path while allowing breath to pass through.

18. The system of claim 1 further comprising a physical activity monitor residing in a processor that operates to determine activity-related energy expenditure from the physical activities and a measured resting energy expenditure of the user.

19. The system of claim 18 wherein at least a portion of the physical activities are provided into the processor via a speech recognition algorithm.

20. The system of claim 18 wherein the processor further operates to track a change in the food and beverage intake over the previous day, and provides calorie change associated with the food and beverage intake change.

21. The system of claim 20 wherein the processor includes speech recognition.

22. The system of claim 18 wherein the physical activity monitor further operates to provide time durations and intensities of physical activities.

23. The system of claim 20 wherein the adaptive sampling mechanism operates to provide recommendations to the user to reach a target weight at a target date based, at least, on the measured resting energy expenditure.

24. The system of claim 18 further comprising a means to provide recommendations of time duration of physical activities based at least on the measured resting energy expenditure.

25. The system of claim 20 wherein the adaptive sampling mechanism operates to determine normalized resting energy expenditure based on the resting energy expenditure and physical parameters of the user, including weight and height.

26. The system of claim 25 wherein the adaptive sampling mechanism operates to determine a physiological index that indicates the user'"'"'s health or fitness status by comparing the measured normalized resting energy expenditure of the user with that of the populations.

27. A system for measuring and tracking metabolic rate comprising:

a mouthpiece having an inlet for the introduction of exhaled breath into a flow path;

wherein the mouthpiece includes at least one orifice with a cross sectional area in the range of 4 mm² to 40 mm² in the flow path, wherein the flow path comprises a detection chamber where at least one gas component in the exhaled breath is detected and where the orifice is at least 50% smaller than the inlet cross sectional area;

wherein the detection chamber comprises;

at least one light emitting diode,

at least one photodiode detector providing a first output signal representing chemical measurements,

a colorimetric sensor cartridge holder, and

a colorimetric sensor cartridge inserted into the sensor cartridge holder;

wherein the colorimetric sensor cartridge comprises;

a solid surface,

a patterned structure in at least one area of the solid surface,

sensing chemicals coated onto the area,

a reference area for signal correction, and

a notch design for positioning;

a differential pressure sensor with a sensor inlet located on the inlet side of the orifice, where the differential pressure sensor provides a second output signal representing pressure measurements; and

an adaptive sampling mechanism that operates to accurately determine resting energy expenditure from pressure and chemical measurements with pre-determined calibration curves that relate the first output signal representing chemical measurements to the chemical concentrations and the second output signal representing pressure measurements.

28. The system of claim 27 wherein the patterned structure comprises at least 81 vertices, and a depth between 20 μ

m and 200 μ

m.