EXHALED BREATH SAMPLING WITH DELIVERY OF GAS

• US 20110009763A1
• Filed: 01/04/2010
• Published: 01/13/2011
• Est. Priority Date: 01/05/2009
• Status: Active Grant

• Current Assignee: Oridion Medical 1987 Limited (Medtronic Plc)
• Original Assignee: Oridion Medical 1987 Limited (Medtronic Plc)
• Inventors: Lain, David, Levitsky, Gershon, Colman, Joshua Lewis
• Granted Patent: US 9,055,888 B2
• Time in Patent Office: Days
• US Class Current: 600/532
• CPC Class Codes: A61B 5/0836 Measuring rate of CO2 production
• CPC Class Codes: A61B 5/087 Measuring breath flow
• CPC Class Codes: A61B 5/097 Devices for facilitating collection of breath or for directing breath into or through measuring devices
• CPC Class Codes: A61M 16/0003 Accessories therefor, e.g. sensors, vibrators, negative pressure
• CPC Class Codes: A61M 16/0057 Pumps therefor
• CPC Class Codes: A61M 16/0666 Nasal cannulas or tubing devices for improving normal breathing through the nose A61F5/08; nose filters A62B23/06; outside holding devices A61M25/02
• CPC Class Codes: A61M 16/0833 T- or Y-type connectors, e.g. Y-piece
• CPC Class Codes: A61M 16/085 Gas sampling
• CPC Class Codes: A61M 16/1005 with O2 features or with parameter measurement
• CPC Class Codes: A61M 2016/003 with a flowmeter
• CPC Class Codes: A61M 2205/3334 Measuring or controlling the flow rate
• CPC Class Codes: A61M 2230/42 Rate
• CPC Class Codes: A61M 2230/43 Composition of exhalation
• CPC Class Codes: A61M 2230/432 partial CO2 pressure (P-CO2)
• CPC Class Codes: A61M 2230/435 partial O2 pressure (P-O2)

Abstract

A system for sampling exhaled breath and for supply of a gas, the system comprising: a gas delivery cannula comprising at least one nasal prong for insertion into a nostril, the nasal prong comprising a distal end; an exhaled breath sampling cannula for insertion into the nostril, the exhaled breath sampling cannula comprising a distal end; and a connector for coupling the gas delivery cannula to the exhaled breath sampling cannula, such that the distal end of the exhaled breath sampling cannula is disposed deeper in the nostril than the distal end of the nasal prong, to reduce dilution of sampled exhaled breath by delivered gas. The connected is configured to facilitate adjustability of an insertion depth of the exhaled breath sampling cannula into said nostril.

Claims

1. A system for sampling exhaled breath and for supply of a gas, the system comprising:

a gas delivery cannula comprising at least one nasal prong for insertion into a nostril, said nasal prong comprising a distal end;

an exhaled breath sampling cannula for insertion into said nostril, said exhaled breath sampling cannula comprising a distal end; and

a connector for coupling said gas delivery cannula to said exhaled breath sampling cannula, such that the distal end of said exhaled breath sampling cannula is disposed deeper in said nostril than the distal end of said nasal prong, to reduce dilution of sampled exhaled breath by delivered gas,

wherein said connected is configured to facilitate adjustability of an insertion depth of said exhaled breath sampling cannula into said nostril.

2. The system according to claim 1, wherein said exhaled breath sampling cannula further comprises multiple scale marks indicating gas flow rates, so that said adjustability of the insertion depth can be correlated with a flow rate of delivered gas.

3. The system according to claim 1, wherein said exhaled breath sampling cannula further comprises multiple apertures adjacent to the distal end of said exhaled breath sampling cannula.

4. The system according to claim 1, wherein said nasal prong of said gas delivery cannula further comprises multiple apertures adjacent to the distal end of said nasal prong.

5. The system according to claim 1, further comprising a capnograph connected to a proximal end of said exhaled breath sampling cannula, for measuring a carbon dioxide (CO₂) level in exhaled breath.

6. The system according to claim 1, further comprising a gas flow generator connected to said gas delivery cannula, for delivering gas through said gas delivery cannula.

7. The system according to claim 1, wherein said gas comprises oxygen.

8. The system according to claim 1, wherein said exhaled breath sampling cannula is adapted to sample the exhaled breath for measuring a CO₂ level.

9. An apparatus for sampling exhaled breath and for supply of a gas, the apparatus comprising:

a gas delivery cannula comprising at least one nasal prong, said nasal prong comprising a distal end; and

an exhaled breath sampling cannula comprising a distal end,

wherein said nasal prong and said exhaled breath sampling cannula are attached together along a portion of their length, such that the distal end of said exhaled breath sampling cannula protrudes beyond the distal end of said nasal prong, to reduce dilution of sampled exhaled breath by delivered gas.

10. A cannula for sampling exhaled breath and for supply of a gas, the cannula comprising:

a gas delivery channel extending internally inside the cannula and terminating at a distal end; and

an exhaled breath sampling channel extending internally inside the cannula and terminating at a distal end positioned beyond the distal end of said gas delivery channel, to reduce dilution of sampled exhaled breath by delivered gas.

11. A system for sampling exhaled breath and for supply of a gas, the system comprising:

an exhaled breath sampling cannula for insertion into a first nostril of a patient; and

a gas delivery cannula comprising at least one nasal prong adapted for insertion into a second nostril of the patient, said nasal prong having a plurality of apertures for dispersing delivered gas so as to reduce dilution of sampled exhaled breath by delivered gas in a nasal cavity of the patient.

12. A system for sampling of exhaled breath and for supply of a gas, the system comprising:

a gas delivery cannula comprising at least one nasal prong for insertion into a nostril, said nasal prong comprising multiple outlet apertures for dispersing delivered gas so as to reduce dilution of sampled exhaled breath by delivered gas; and

an exhaled breath sampling cannula for insertion into said nostril, said exhaled breath sampling cannula comprising a distal end configured to be disposed at approximately the same depth in the nostril as the outlet apertures of said nasal prong.

13. The system according to claim 12, further comprising a capnograph connected to said exhaled breath sampling cannula, for measuring a CO₂ level.

14. The system according to claim 12, further comprising a gas flow generator connected to said gas delivery cannula, for delivering gas.

15. The system according to claim 12, wherein said gas comprises oxygen.

16. A method for measuring exhaled breath of a patient being supplied with a gas, the method comprising:

providing the patient with a flow of a gas;

reducing the flow of the gas for a predetermined period;

sampling an exhaled breath of the patient while the flow of the gas is reduced, to reduce dilution of the exhaled breath by the flow of the gas.

17. The method according to claim 16, wherein the reducing of the flow of the gas comprises stopping the flow of the gas.

18. The method according to claim 16, wherein the sampling of the exhaled breath comprises:

performing a first sampling during a first exhalation of the patient, wherein previously provided gas is substantially discarded by the patient during the first exhalation; and

performing a second sampling during a second exhalation of the patient, wherein a concentration of previously provided gas in the second exhalation is lower than a concentration of previously provided gas in the first exhalation.

19. The method according to claim 16, further comprising:

calculating a respiration rate of the patient, based on a measured interval between the first sampling and the second sampling; and

adjusting the predetermined period based on the respiration rate, so that the predetermined period extends over essentially two consecutive exhaled breaths.

20. The method according to claim 16, further comprising:

identifying an exhalation timing using a flow sensor; and

synchronizing the predetermined period to extend over essentially two identified exhaled breaths.

21. The method according to claim 16, further comprising estimating an end-tidal CO₂ (EtCO₂) level based on a highest CO₂ peak detected in at least one of a plurality of samplings.

22. A system for sampling exhaled breath and for supply of a gas, the system comprising:

a nose continuer for nasally providing gas to a patient, and comprising a gas inlet for connection to a gas source; and

an exhaled breath sampling cannula for insertion into a nostril, said exhaled breath sampling cannula comprising a distal end,

wherein a distance between said distal end and the gas inlet of said nose continuer is such that dilution of sampled exhaled breath by provided gas is reduced.

23. A system for sampling exhaled breath and for supply of a gas, the system comprising:

an oral-nasal mask for providing gas to a patient, said mask comprising a gas inlet for connection to a gas source; and

an exhaled breath sampling cannula for insertion into a nostril, said exhaled breath sampling cannula comprising a distal end,

wherein a distance between said distal end and the gas inlet of said oral-nasal mask is such that dilution of sampled exhaled breath by provided gas is reduced.

24. A system for sampling exhaled breath and for supply of a gas, the system comprising:

a gas delivery cannula;

a flow sensor configured to identify a timing and an intensity of an exhaled breath;

an exhaled breath sampling cannula; and

a controller configured to synchronize sampling of exhaled breath with said timing and intensity, such that exhaled breath is sampled when at a peak of said intensity.

25. The system according to claim 24, wherein said controller is further configured to reduce gas delivery at essentially said peak of intensity.

26. A system for sampling exhaled breath and for supply of a gas, the system comprising:

an exhaled breath sampling cannula comprising a nasal prong; and

an aerodynamic gas regulator comprising a diffuser and a nasal prong, said regulator being configured to supply gas through both of said diffuser and said nasal prong during inhalation, and to supply gas primarily through said diffuser during exhalation, so that dilution of sampled exhaled breath by supplied gas is reduced during exhalation.