Systems, apparatus, and methods related to modeling, monitoring, and/or managing metabolism

• US 10,638,956 B2
• Filed: 12/07/2017
• Issued: 05/05/2020
• Est. Priority Date: 07/27/2015
• Status: Active Grant

• Current Assignee: Massachusetts Institute of Technology
• Original Assignee: Massachusetts Institute of Technology
• Inventors: Candell, Lawrence M., Ferraiolo, Christopher, Shaw, Gary A., Siegel, Andrew M., Zogbi, George, McClung, Holly Lehmann, Hoyt, Reed Wasson, Thompson, Kyle
• Primary Examiner(s): Cheng, Jacqueline
• Assistant Examiner(s): Portillo, Jairo H
• Application Number:
  US15/835,049
• Publication Number:
  US 20180125391A1
• Time in Patent Office: 880 Days
• Field of Search: None
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 2560/0247 for compensation or correction of the measured physiological value
• CPC Class Codes: A61B 5/0816 Measuring devices for examining respiratory frequency measuring frequency of electric signals G01R23/00
• CPC Class Codes: A61B 5/082 Evaluation by breath analysis, e.g. determination of the chemical composition of exhaled breath A61B5/083, A61B5/091 take precedence
• 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 5/0833 Measuring rate of oxygen consumption
• CPC Class Codes: A61B 5/0836 Measuring rate of CO2 production
• CPC Class Codes: A61B 5/0871 Peak expiratory flowmeters
• CPC Class Codes: A61B 5/097 Devices for facilitating collection of breath or for directing breath into or through measuring devices
• CPC Class Codes: A61B 5/4866 Evaluating metabolism A61B5/083 takes precedence
• CPC Class Codes: A61B 5/7275 Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: G09B 19/00 Teaching not covered by other main groups of this subclass teaching or practice apparatus for gun-aiming or gun-laying F41G3/26
• CPC Class Codes: G09B 19/0092 Nutrition

Abstract

Systems, apparatus, and methods related to modeling, monitoring, and/or managing metabolism of a subject include measuring a respiratory quotient (RQ) level in a subject and/or optimizing and executing a nonlinear feedback model to model energy substrate utilization in the subject based on at least one of a macronutrient composition and caloric value of food consumed by the subject, an intensity and duration of activity by the subject, a rate and maximum capacity of glycogen storage in the subject, a rate and maximum capacity of de novo lipogenesis in the subject, a quality and duration of sleep by the subject, and/or an RQ level in the subject.

Claims

1. A passive side-stream sampling system comprising:

a sample tube having an input port to receive an exhalation from a subject and a sidestream sampling port to discharge a fraction of the exhalation;

a flow restrictor, disposed in the sample tube, to cause the fraction of the exhalation to exit the sample tube via the sidestream sampling port proportional to a flow rate of the exhalation over an entire duration of the exhalation; and

a mixing chamber, in fluid communication with the sidestream sampling port, with a first sensor to measure a carbon dioxide level and a second sensor to measure an oxygen level of the fraction of the exhalation, the mixing chamber having an exhaust valve with a cracking pressure of less than 1 mm H₂O to sustain breath sampling toward an end of the exhalation.

2. The passive side-stream sampling system of claim 1, wherein the flow restrictor comprises a venturi.

3. The passive side-stream sampling system of claim 1, wherein the flow restrictor is configured to cause the fraction of the exhalation to exit the sample tube via the sidestream port by creating a back pressure which forces the fraction of the exhalation into the sidestream port.

4. The passive side-stream sampling system of claim 3, wherein the flow restrictor is configured such that the fraction of the exhalation forced into the sidestream port remains stable over the exhalation.

5. The passive side-stream sampling system of claim 3, wherein the flow restrictor is configured such that the fraction of the exhalation forced into the sidestream port increases with increasing exhalation flow rate.

6. The passive side-stream sampling system of claim 1, wherein the mixing chamber is configured to accumulate fractions of successive exhalations.

7. The passive side-stream sampling system of claim 1, further comprising:

a membrane, disposed in the sample tube, to reduce and/or equilibrate a temperature and humidity of the exhalation with ambient conditions.

8. The passive side-stream sampling system of claim 1, further comprising:

a differential pressure flow sensor, in fluid communication with the sample tube, to measure a volumetric flow of the exhalation.

9. The passive side-stream sampling system of claim 1, wherein the mixing chamber has a longest edge less than about 2 inches long.

10. A method of sampling an exhalation from a subject, the method comprising:

receiving, via an input of a sample tube, the exhalation from the subject;

restricting, with a flow restrictor disposed in the sample tube, a flow of the exhalation through the sample tube, the flow restrictor causing a fraction of the exhalation proportional to a flow rate of the exhalation to exit the sample tube via a sidestream sampling port over an entire duration of the exhalation;

receiving, with a mixing chamber in fluid communication with the sidestream sampling port, the fraction of the exhalation;

measuring, in the mixing chamber, a carbon dioxide level and an oxygen level of the fraction of the exhalation; and

sustaining, with an exhaust valve having a cracking pressure of less than 1 mm H₂O disposed at an end of the mixing chamber, breath sampling toward an end of the exhalation.

11. The method of claim 10, wherein restricting the flow of the exhalation comprises creating a back pressure that forces the fraction of the exhalation into the sidestream port.

12. The method of claim 11, wherein the fraction of the exhalation forced into the sidestream port remains stable over the exhalation.

13. The method of claim 10, wherein restricting the flow of the exhalation causes the fraction of the exhalation to exit the sample tube via the sidestream sampling port at a flow rate proportional to a flow rate of the exhalation.

14. The method of claim 10, wherein the exhalation is a first exhalation and further comprising:

accumulating a fraction of a second exhalation in the mixing chamber via the sample tube and the sidestream sampling port.

15. The method of claim 14, wherein measuring the carbon dioxide level and the oxygen level of the fraction of the first exhalation comprises measuring the carbon dioxide level and the oxygen level of a mixture of the fraction of the first exhalation and the fraction of the second exhalation.

16. The method of claim 10, further comprising:

reducing and/or equilibrating a temperature and humidity of the exhalation with ambient conditions.

17. The method of claim 10, further comprising:

measuring a volumetric flow of the exhalation.