Calorimetry systems and methods

• US 6,475,158 B1
• Filed: 10/24/2000
• Issued: 11/05/2002
• Est. Priority Date: 10/24/2000
• Status: Expired due to Term

• Current Assignee: Korr Medical Technologies, Inc.
• Original Assignee: Korr Medical Technologies, Inc.
• Inventors: Orr, Joseph A., Kofoed, Scott A., Durst, Kevin
• Primary Examiner(s): Shaver, Kevin
• Assistant Examiner(s): Natnithithadha, Navin
• Application Number:
  US09/694,954
• Time in Patent Office: 742 Days
• Field of Search: 600/529-538
• US Class Current: 600/531
• CPC Class Codes: A61B 5/0002 Remote monitoring of patients using telemetry, e.g. transmission of vital signals via a communication network A61B5/07 takes precedence; transmission systems for measured values G08C; transmission H04B; transmission of digital information H04L; wireless communication networks H04W
• CPC Class Codes: A61B 5/024 Detecting, measuring or recording pulse rate or heart rate A61B5/0205, A61B5/021 take precedence
• CPC Class Codes: A61B 5/0833 Measuring rate of oxygen consumption
• CPC Class Codes: A61B 5/087 Measuring breath flow

Abstract

A calorimeter configured to determine a metabolic rate of an individual based on measurements of the individual'"'"'s respiration. The calorimeter includes an inlet, a flow sensor, a mixing chamber, a gas sensor, and a calibrator. Each of these elements is located along a flow path through the calorimeter. The calibrator of the calorimeter includes a fan that is configured to force calibration gases, such as room air, through or past the gas sensor. A cardiac rate monitor is associated with a processor of the calorimeter. The processor is configured to substantially simultaneously determine and establish a relationship between the cardiac rate of the individual and the measured respiratory parameters or the metabolic rate of the individual. Data representative of this relationship may be communicated to a processor or memory of a portable calorimeter to be subsequently used by the individual. The portable calorimeter, which can be worn by the individual, includes a cardiac rate monitor that measures the cardiac rate of the individual and communicates data representative of the individual'"'"'s cardiac rate to the processor, which then determines the metabolic rate of the individual based on relationship data obtained from the respiratory-based calorimeter. Methods of calibrating and using the calorimeters are also disclosed.

Claims

1. A calorimeter, comprising:

an inlet configured to communicate with an airway of an individual to receive expiratory gases from the individual;

a respiratory flow detection component in communication with said inlet;

a mixing chamber in communication with said inlet to receive at least one expiratory breath from the individual and average the respiratory gases of said at least one expiratory breath;

a respiratory gas measurement component in communication with said mixing chamber and downstream therefrom to receive expiratory respiration from the individual under pressure of the individual'"'"'s expiratory breaths;

an outlet located so as to receive gas from said respiratory gas measurement component and to expel the gas from the calorimeter; and

a calibrator in communication with at least said respiratory gas measurement component and said outlet and positioned so as to draw calibration gas into the calorimeter through said outlet to a location for detection by at least said respiratory gas measurement component.

2. The calorimeter of claim 1, wherein said respiratory gas measurement component comprises an oxygen sensor.

3. The calorimeter of claim 1, further comprising:

a flow meter in communication with said respiratory flow detection component; and

a gas meter in communication with said respiratory gas measurement component.

4. The calorimeter of claim 3, wherein said gas meter comprises an oxygen meter.

5. The calorimeter of claim 3, further comprising a processor in communication with said flow sensor and said gas sensor.

6. The calorimeter of claim 5, wherein said processor also communicates with a cardiac rate monitor.

7. The calorimeter of claim 1, wherein said inlet includes a 1-way valve positioned so as to control the movement of gas through said inlet.

8. The calorimeter of claim 1, wherein said mixing chamber comprises a valve positioned so as to control pressure within said mixing chamber.

9. The calorimeter of claim 8, wherein said mixing chamber comprises a mixing element, said mixing element and a fan of said calibrator oriented so as to control positioning of said valve.

10. The calorimeter of claim 1, further comprising a valve configured to control the flow of calibration gas into said location for detection by at least said respiratory gas measurement component.

11. The calorimeter of claim 10, wherein said valve is positionable to prevent exposure of said respiratory gas measurement component to room air as the individual breathes into said inlet.

12. A system for measuring a metabolic rate of an individual, comprising:

a calorimeter including;

an inlet configured to receive expiratory respiration from the individual;

a respiratory flow sensor in communication with said inlet;

a mixing chamber in communication with said inlet to receive at least one expiratory breath from the individual; and

a gas sensor in communication with said mixing chamber;

a flow meter in communication with said respiratory flow sensor;

a gas meter in communication with said gas sensor;

a cardiac rate monitor;

a processor in communication with said flow meter, said gas meter, and said cardiac rate monitor; and

a portable calorimeter configured to communicate with said processor so as to receive data therefrom.

13. The system of claim 12, wherein said calorimeter further includes a calibrator configured to introduce room air into the presence of said gas sensor.

14. The system of claim 12, wherein said processor is configured to determine the metabolic rate based on flow data generated by said flow meter and respiratory gas data generated by said gas meter.

15. The system of claim 14, wherein said portable calorimeter is configured to store data representative of the metabolic rate of the individual and to employ such stored data along with measured cardiac rate data to determine a metabolic rate of the individual without again requiring use of said calorimeter.

16. The system of claim 12, wherein:

said gas sensor comprises at least one of an oxygen sensor and a carbon dioxide sensor; and

said gas meter comprises at least one of an oxygen meter and a carbon dioxide meter.

17. A method for measuring a metabolic rate of an individual, comprising:

evaluating expiratory respiration of the individual to determine an oxygen consumption of the individual;

measuring a cardiac rate of the individual substantially concurrently with said evaluating;

transmitting data representative of said oxygen consumption and said cardiac rate to a portable calorimeter;

measuring a cardiac rate of the individual following said transmitting; and

calculating the metabolic rate of the individual based on said transmitted data and said cardiac rate measured by said portable calorimeter.

18. The method of claim 17, further comprising disassociating said portable calorimeter from said processor.

19. A portable calorimeter configured to be worn by an individual, comprising:

a processor;

a cardiac rate monitor in communication with said processor, said cardiac rate monitor being configured to communicate signals representative of a cardiac rate of the individual to said processor, said processor being configured to determine a metabolic rate of the individual based on previously obtained respiratory or metabolic rate data of the individual; and

an output element in communication with said processor and being configured to communicate information representative of at least the metabolic rate of the individual.

20. The portable calorimeter of claim 19, wherein said output element is configured to communicate at least one of an amount of energy expended by the individual over a period of time and a rate at which the individual is expending energy.

21. A calorimeter, comprising:

a flow path in communication with an airway of an individual;

a respiratory gas measurement component positioned along said flow path so as to receive gases exhaled by the individual without use of a valve or pump; and

a calibrator in communication with said flow path and configured to cause at least one calibration gas to flow through said flow path in an opposite direction from that in which gases exhaled by the individual flow so as to expose said respiratory gas measurement component to said at least one calibration gas.

22. The calorimeter of claim 21, wherein said calibrator comprises a fan.