Portable Alveolar Gas Meter

• US 20070232950A1
• Filed: 05/25/2005
• Published: 10/04/2007
• Est. Priority Date: 05/26/2004
• Status: Active Grant

• Current Assignee: Regents of the University of California (University of California)
• Original Assignee: Regents of the University of California (University of California)
• Inventors: West, John
• Granted Patent: US 8,545,415 B2
• Time in Patent Office: Days
• US Class Current: 600/532
• CPC Class Codes: A61B 2560/0462 Apparatus with built-in sensors
• 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 5/097 Devices for facilitating collection of breath or for directing breath into or through measuring devices

Abstract

A portable alveolar gas measurement device and method of determining at least one alveolar gas level are disclosed. The device includes a structure that receives a sample portion of breath, and a gas sensor in communication with the structure that detects a gas level of a gas within the sample portion and provides a first signal indicative of the level. The device further includes circuitry coupled at least indirectly to the gas sensor, where the circuitry receives at least one of the first signal and a second signal related to the first signal, and where the circuitry provides at least some assistance in determining whether a portion of information provided by the at least one signal is used as an indication of an alveolar gas level. Additionally, the device includes an output device coupled to the circuitry that provides an output indicative of the first alveolar gas level.

Claims

1. A portable alveolar gas measurement device comprising:

a structure that receives a sample portion of breath;

a first gas sensor in communication with the structure that detects a first gas level of a first gas within the sample portion and provides a first signal indicative of the first gas level;

circuitry coupled at least indirectly to the first gas sensor, wherein the circuitry receives at least one of the first signal and a second signal that is related to the first signal, and wherein the circuitry provides at least some assistance in determining whether a portion of information provided by the at least one signal is used as an indication of a first alveolar gas level; and

an output device coupled to the circuitry that provides an output indicative of the first alveolar gas level as determined at least in part with the assistance of the circuitry.

2. The portable alveolar gas measurement device of claim 1, wherein the circuitry is found on a handheld computer device that includes a display that is the output device.

3. The portable alveolar gas measurement device of claim 2, wherein the circuitry on the handheld computer device provides the assistance in determining whether the portion of the information is used as an indication of the first alveolar gas level by causing the display to provide a visual indication of variation of the first gas level over time based upon the at least one signal, whereby it is possible for a user to determine when a steady state breath pattern has occurred and as a result determine that the portion of information within the at least one signal is indicative of the first alveolar gas level.

4. The portable alveolar gas measurement device of claim 2, wherein the circuitry on the handheld computer device provides assistance in determining whether the portion of the information is used as an indication of the first alveolar gas level by monitoring variation of the first gas level over time based upon the at least one signal, determining when a steady state breath pattern has occurred, and subsequently determining that the portion of information within the at least one signal is indicative of the first alveolar gas level.

5. The portable alveolar gas measurement device of claim 4, wherein the portion of information concerns at least one of a relative minimum and a relative maximum of the second signal, and wherein the display of the output device is capable of providing at least one of graphical and alphanumeric information substantially in real-time.

6. The portable alveolar gas measurement device of claim 1, wherein the first gas sensor at least one of continuously detects the first gas level and detects the first gas level at a particular determined time.

7. The portable alveolar gas measurement device of claim 6, wherein the first gas sensor continuously detects the first gas level and provides the first signal in response thereto, and wherein the circuitry determines the portion of the information to be at least one value of the first signal obtained during a first time period.

8. The portable alveolar gas measurement device of claim 7, wherein the circuitry includes an operator-actuatable switch and determines the time period based upon a triggering of the switch.

9. The portable alveolar gas measurement device of claim 8, wherein the switch is actuated by at least one of a human subject and an additional human being when the human subject has substantially fully expired a breath into the structure.

10. The portable alveolar gas measurement device of claim 9, wherein the switch causes a sample and hold circuit portion of the circuitry to at least one of store a current value of the first signal, process the current value of the first signal to obtain a related value, and output at least one of the current value and the related value as the second signal.

11. The portable alveolar gas measurement device of claim 9, wherein the circuitry is at least partly formed on a circuit board located within a housing that also supports the first gas sensor and the structure.

12. The portable alveolar gas measurement device of claim 11, wherein the output device is a voltmeter supported along an exterior surface of the housing, and wherein the voltmeter displays an output based upon the second signal, which is provided to the voltmeter by the circuitry.

13. The portable alveolar gas measurement device of claim 1, wherein at least one of the output device and another indicator associated with the output device serves as a warning indicator that provides a warning indication when the first alveolar gas level is in an abnormal range.

14. The portable alveolar gas measurement device of claim 1, wherein the first gas includes at least one of oxygen gas and carbon dioxide gas.

15. The portable alveolar gas measurement device of claim 14, wherein the first gas is one of oxygen gas and carbon dioxide gas, and wherein the first alveolar gas is the other of the oxygen gas and the carbon dioxide gas, wherein the first alveolar gas is calculated by the circuitry based at least indirectly upon the first signal indicative of the first gas.

16. The portable alveolar gas measurement device of claim 1, further comprising a second gas sensor in communication with the structure that detects a second gas level of a second gas within the sample portion and provides a third signal indicative of the second gas level;

17. The portable alveolar gas measurement device of claim 16, wherein the first signal is representative of a first partial pressure of oxygen gas and the third signal is representative of a second partial pressure of carbon dioxide gas.

18. The portable alveolar gas measurement device of claim 1, wherein the circuitry includes at least one of hardwired circuit componentry, a power converter, a microprocessor, a programmable logic device, a computer, an analog-to-digital converter, other means for processing, a sample and hold switch, a power switch, a power source, and a potentiometer, and wherein the gas sensor includes at least one of a gas sensing cell, a gas sensor circuit board, and a gas pump.

19. The portable alveolar gas measurement device of claim 1, wherein the structure is a tubular structure into which it is intended that at least one of a human subject and an animal subject at least one of exhale and inhale.

20. The portable alveolar gas measurement device of claim 19, wherein the structure further includes at least one valve limiting inflow of outside air in order to prevent contamination of the sample portion.

21. The portable alveolar gas measurement device of claim 19, wherein the structure includes a disposable mouthpiece portion.

22. The portable alveolar gas measurement device of claim 1, wherein the first gas sensor is coupled to the structure and at least some of the sample portion is caused to pass in proximity to the first gas sensor due to operation of a pump coupled to at least one of the gas sensor and the circuitry.

23. The portable alveolar gas measurement device of claim 1, wherein the device includes a housing within which is situated at least the first gas sensor, and an exterior case coupled to the housing, wherein the exterior case is configured to support at least one of a personal digital assistant, a handheld computer device, a cellular telephone, and another computerized device.

24. A method of determining at least one alveolar gas level of a human subject, the method comprising:

transporting a portable device for determining the at least one alveolar gas level from a first location to a second location proximate the human subject;

receiving a breath of the human subject within a receiving structure of the device to obtain a sample portion of the breath;

sensing a first gas level associated with the sample portion;

providing a signal representative of the sensed first gas level; and

providing an output based at least indirectly upon the signal, wherein at least a part of the output is indicative of a first alveolar gas level of the human subject.

25. The method of claim 24, further comprising:

determining at least one of;

whether a portion of information contained in the signal is used as an indication of the first alveolar gas level of the human subject; and

whether the part of the output is indicative of the first alveolar gas level.

26. The method of claim 25, wherein the determining includes:

observing the output;

ascertaining when the output is representative of a steady breathing pattern;

causing the human subject to provide an additional expiration into the receiving structure; and

identifying the part of the output corresponding to a time period during the additional expiration as being indicative of the first alveolar gas level.

27. The method of claim 25, wherein the determining includes:

observing that the human subject has substantially completed an expiration into the receiving structure; and

receiving a trigger signal from a sample-and-hold switch when the expiration has been substantially completed, wherein the trigger signal from the switch precipitates recordation of the portion of information within a sample and hold circuit.

28. The method of claim 24, wherein the output is at least one of a graphical output provided by way of a handheld computer and an alphanumeric output provided by way of a voltmeter.

29. The method of claim 24,

wherein at least one of the following is true:

the first alveolar gas level concerns a first gas and the first gas level concerns a second gas; and

an additional output is provided that is indicative of a second alveolar gas level, wherein the first alveolar gas level is an oxygen gas level and the second alveolar gas level is a carbon dioxide gas level.

30. An apparatus for determining at least one alveolar gas level, the apparatus comprising:

a housing;

a gas sensing device supported within the housing;

a receiving structure capable of receiving breath and coupled to the gas sensing device by a sampling passage; and

means for processing and outputting information based upon at least one signal provided by the gas sensing device as a result of exposure of the gas sensing device to at least a portion of the breath;

wherein the means for processing and outputting at least one of identifies and assists in the identification of alveolar gas level information included within at least one of the signal and the output information; and

wherein the apparatus is configured to be portably moved among a plurality of locations.