PORTABLE METABOLIC ANALYZER SYSTEM

• US 20150369795A1
• Filed: 01/21/2014
• Published: 12/24/2015
• 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
• Granted Patent: US 10,078,074 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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:

an adaptive sampling mechanism for the introduction of exhaled breath into a flow path;

at least one orifice with an appropriate cross sectional area in the flow path;

a pressure sensor with an inlet located on the inlet side of the orifice;

a calibration curve that relates the output signal of the pressure sensor to the exhaled volume flow rate; and

a means to determine the resting energy expenditure.

2. The system of claim 1 wherein the adaptive algorithm comprises:

a means to pre-determine the natural breathing pattern of an individual; and

a means to play audio with a rhythm and volume, or video with motion sequence adjusted to the pre-determined natural breathing pattern.

3. The system of claim 2 wherein the adaptive algorithm further comprises:

a means to detect changes in the breathing pattern over time;

a means to memorize changes in the breathing pattern over time; and

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

4. The system of claim 1 wherein the adaptive algorithm comprises:

a means to detect breathing patterns;

a means to memorize breathing patterns; and

a means to play audio with rhythm and volume or video with motion sequence in a measurement according to the breathing pattern detected in previous measurements.

5. The system of claim 1 wherein the adaptive algorithm comprises:

a means to detect breathing patterns;

a means to memorize breathing patterns;

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

a means to determine volume flow rate based on the data acquired during the time intervals; and

a means to play audio with rhythm and volume or video motion sequence in a measurement according to the regular breathing pattern detected in previous measurements.

6. The system of claim 1 wherein the orifice has a cross sectional area between 4 mm² and 40 mm².

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

8. The system of claim 1 wherein the cross sectional area of the flow path at the position of the inlet of the pressure sensor is at least 50% larger than the cross sectional area of the orifice.

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

10. The system of claim 1 comprising means to determine the resting energy expenditure with the Weir equation using at least measured exhaled volume flow rate.

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

13. 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.

14. The system of claim 13 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.

15. The system of claim 14 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.

16. The system of claim 15 wherein the patterned structure comprises at least 81 vertices, and a depth between 20 um and 200 um.

17. The system of claim 14 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.

18. The system of claim 13 wherein a fan is attached to the detection chamber via a one-way valve.

19. The system of claim 1 further comprising a filter positioned between the 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.

20. The system of claim 1 further comprising a means to determine physical activity-related energy expenditure from the physical activities and the measured resting energy expenditure of the user.

21. The system of claim 20 wherein at least a portion of the physical activities are provided into the apparatus via a speech recognition algorithm.

22. The system of claim 1 further comprising a means to track a change in the food and beverage intake over the previous day, and a means to provide calorie change associated with the food and beverage intake change.

23. The system of claim 22 wherein the means to track the change in the food intake includes speech recognition.

24. The system of claim 20 further comprising a means to provide time durations and intensities of physical activities.

25. The system of claim 22 further comprising a means to provide recommendations to the user to reach a target weight at a target date based, at least, on the measured resting energy expenditure.

26. The system of claim 20 further comprising a means to provide recommendations of time duration of physical activities based at least on the measured resting energy expenditure.

27. The system of claim 1 further comprising a means to determine normalized resting energy expenditure based on the resting energy expenditure and physical parameters of the user, including weight and height.

28. The system of claim 27 further comprising a means 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.

12. The system of claim 12 wherein the fan is connected to the flow path via a one way valve.