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

Patent metadata

Field	Value
Publication number	US-10638956-B2
Application number	US-201715835049-A
Country	US
Kind code	B2
Filing date	Dec 7, 2017
Priority date	Jul 27, 2015
Publication date	May 5, 2020
Grant date	May 5, 2020

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.

First claim

The invention claimed is:

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 H 2 O 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 H 2 O 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.

Assignees

• Massachusetts Inst Technology

Inventors

• Candell Lawrence M
• Ferraiolo Christopher
• Shaw Gary A
• Siegel Andrew M
• Zogbi George
• Mcclung Holly Lehmann
• Hoyt Reed Wasson
• Thompson Kyle

Classifications

• A61B5/0833

  Measuring rate of oxygen consumption · CPC title

• A61B5/0836

  Measuring rate of CO2 production · CPC title

• A61B5/7275

  Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor · CPC title

• A61B5/083 Primary

  Measuring rate of metabolism by using breath test, e.g. measuring rate of oxygen consumption · CPC title

• A61B5/097

  Devices for facilitating collection of breath or for directing breath into or through measuring devices · CPC title