Respiratory humidification system

• US 7,263,994 B2
• Filed: 09/17/2003
• Issued: 09/04/2007
• Est. Priority Date: 06/17/1997
• Status: Expired due to Fees

• Current Assignee: Fisher & Paykel Healthcare Limited
• Original Assignee: Fisher & Paykel Healthcare Limited
• Inventors: Gradon, Lewis George, McPhee, Stephen William, Leonard, Peter John, Seakins, Paul John
• Primary Examiner(s): Douglas; Steven O.
• Application Number:
  US10/664,385
• Publication Number:
  US 20040060558A1
• Time in Patent Office: 1,448 Days
• Field of Search: 128/203.12, 128/203.16, 128/203.17, 128/203.26, 128/204.17, 128/204.22, 732/041.9, 732/042.2, 732/042.3, 738/614.7, 738/615.2, 738/615.3
• US Class Current: 128/204.22
• CPC Class Codes: A61M 16/0051 with alarm devices
• CPC Class Codes: A61M 16/0066 Blowers or centrifugal pumps
• CPC Class Codes: A61M 16/024 including calculation means, e.g. using a processor
• CPC Class Codes: A61M 16/0841 for sampling
• CPC Class Codes: A61M 16/1075 by influencing the temperature A61M16/1045 takes precedence
• CPC Class Codes: A61M 16/109 the humidifying liquid or the beneficial agent
• CPC Class Codes: A61M 16/1095 in the connecting tubes
• CPC Class Codes: A61M 16/16 Devices to humidify the respiration air A61M16/1045 takes precedence
• CPC Class Codes: A61M 16/161 with means for measuring the humidity
• CPC Class Codes: A61M 16/162 Water-reservoir filling system, e.g. automatic
• CPC Class Codes: A61M 2016/0039 in the inspiratory circuit
• CPC Class Codes: A61M 2205/18 with alarm
• CPC Class Codes: A61M 2205/3331 Pressure; Flow
• CPC Class Codes: A61M 2205/3368 Temperature
• CPC Class Codes: G01F 1/684 Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
• CPC Class Codes: G01F 1/6842 with means for influencing the fluid flow
• CPC Class Codes: G01F 1/6888 Thermoelectric elements, e.g. thermocouples, thermopiles
• CPC Class Codes: G08B 21/16 Combustible gas alarms
• CPC Class Codes: Y10S 261/65 Vaporizers

Abstract

A flow probe for use in a humidification system is positioned in a humidified gases flow such as that which is provided to a patient in a hospital environment. The flow probe is designed to provide both temperature and flow rate sensing of the gases flow by incorporating two sensors into the gases flow. The flow probes are shaved and aligned within the gases flow to enable accurate gas flow readings to be taken whilst reducing the occurrence of condensation on the sensors. The flow probe can also be included in a humidification control systems to provide a patient with a desired humidity level or simplify the amount of user input required to set humidity levels. Furthermore, the flow probe can provide a controller with flow information which may then be used to determine certain conditions that could prove to be dangerous to a patient.

Claims

1. A breathing circuit component or connector for interconnection with a breathing assistance apparatus and having an interior defining a longitudinal axis for conveying respiratory gas, said breathing circuit component or connector capable of receiving an associated sensor, said breathing circuit component or connector comprising:

a sensor entry port extending perpendicularly from said component or connector and configured to receive the sensor, said sensor entry port being defined by a wall, and

a locating notch extending from said wall, said locating notch configured to receive a complementary locating tooth from the sensor, the interconnection of said notch and a tooth providing a predetermined orientation of the sensor which is fixed relative to the longitudinal axis.

2. A breathing circuit component or connector as claimed in claim 1 further comprising a sensor for locating within said sensor entry port, said sensor including

sensor housing adapted for positioning in said gas flow, said sensor housing having a longitudinal axis substantially perpendicular to said gas flow and a sensing end,

a locating tooth configured to mate with said notch, and

at least one projecting tab, extending laterally from said sensor housing, said at least one projecting tab providing surfaces which enable liquid condensate to disperse away from said sensing end of said sensor housing.

3. A breathing circuit component or connector as claimed in claim 2 wherein said sensor comprises two projecting tabs.

4. A breathing circuit component or connector as claimed in claim 2 or claim 3 wherein said two projecting tabs are oppositely positioned around said sensor housing.

5. A breathing circuit component or connector as claimed in claim 2 or claim 3 wherein each said projecting tab is aligned parallel to said gas flow.

6. A breathing circuit component or connector as claimed in claim 2 or claim 3 wherein liquid condensate is dispersed along lines of intersection between said sensor housing and each said tab, there existing a localised area of low surface tension along said lines of intersection.

7. A breathing circuit component or connector as claimed in claim 2 or claim 3 wherein said sensor comprises a temperature sensor housing and a flow rate sensor housing.

8. A breathing circuit component or connector as claimed in claim 7 wherein said temperature sensor housing and said flow rate sensor housing each comprise a temperature dependent resistance.

9. A breathing circuit component or connector as claimed in claim 8 wherein temperature dependent resistance is occasionally heated to a predetermined difference temperature above the temperature of said gas flow, and the power required to maintain said predetermined difference temperature providing an indication of the flow rate of said gas.

10. A breathing circuit component or connector as claimed in claim 7 wherein said flow rate sensor housing is exposed at or near the sensing end while said temperature sensor housing is encapsulated at or near the sensing end of the temperature sensor housing.

11. A breathing circuit component or connector as claimed in claim 9 wherein said temperature and flow rate sensor housing are spaced across said gas flow in order that heat produced from said flow rate sensor housing has substantially minimal effect on said temperature sensor housing.

12. A breathing circuit component or connector as claimed in claim 11 wherein said flow rate sensor housing is positioned downstream of said temperature sensor housing in order that heat produced by said flow rate sensor housing does not affect said temperature sensor housing.

13. A breathing circuit component or connector as claimed in claim 2 or claim 3 wherein said gas flow is channeled within a conduit of known cross-sectional area, at least in the region adjacent said sensor, and is provided with said sensor entry port adapted to receive said sensor, the positioning of said temperature and flow rate sensor housing relative to said gas flow being controlled by the interconnection of said locating notch and tooth.

26. A breathing circuit component or connector as claimed in claim 1, further comprising a sensor mounted within said sensor entry port.

14. A breathing circuit component or connector capable of receiving an associated sensor and having an interior defining a longitudinal axis for conveying respiratory gas, said breathing circuit component or connector, comprising:

a gas inlet communicating with said interior and configured to connect to an outlet of humidifier or other breathing assistance apparatus,

a gas outlet communicating with said interior and configured to connect to a conduit,

a sensor entry port configured to receive the sensor, said sensor entry port being defined by a wall, and

a locating notch extending from said wall, said locating notch configured to receive a complementary locating tooth from the sensor, the interconnection of said notch and a tooth providing a predetermined orientation of the sensor which is fixed relative to the longitudinal axis.

15. A breathing circuit component or connector as claimed in claim 14 wherein said sensor entry port comprises an annular cylinder extending perpendicularly from said component or connector and having a passage communicating with and extending from said interior, said passage being substantially perpendicular to said interior.

16. A breathing circuit component or connector as claimed in claim 15 wherein said locating notch is at an end of said cylinder distant said interior.

17. A breathing circuit component or connector as claimed in claim 16 wherein said notch is substantially “

V”

shaped.

18. A breathing circuit component or connector as claimed in claim 17 wherein a base of said “

V”

shaped notch is rounded.

19. A breathing circuit component or connector as claimed in claim 18 wherein a diameter of said passage ensures a substantially airtight seal against the sensor located therein.

20. A breathing circuit component or connector as claimed in claim 19 wherein said inlet includes an exterior surface comprising a tapered male portion configured to connect to a tapered female portion of an inner surface of an outlet of humidifier, or other breathing assistance apparatus.

21. A breathing circuit component or connector as claimed in claim 20 wherein said gas outlet includes an inner surface configured to form a substantially airtight seal against an exterior surface of a conduit.

22. A breathing circuit component or connector as claimed in claim 21 wherein said inner surface of said gas outlet and the exterior surface of the conduit are permanently bonded.

23. A breathing circuit component or connector as claimed in claim 22 further comprising a flow sensor having a substantially cylindrical exterior configured to form an airtight seal against said passage, a sensing end and a locating tooth configured to mate with said locating notch and locate said sensing end within said interior.

24. A breathing circuit component or connector as claimed in claim 23 wherein said tooth is substantially “

V”

shaped.

25. A breathing circuit component or connector as claimed in claim 24 wherein a base of said “

V”

shaped tooth is rounded.

27. A breathing circuit component or connector as claimed in claim 14, further comprising a sensor mounted within said sensor entry port.

28. A breathing circuit component or connector for interconnection with a breathing assistance apparatus and having an interior for conveying respiratory gas, said breathing circuit component or connector capable of receiving an associated sensor, said breathing circuit component or connector comprising:

a sensor entry port extending perpendicularly from said component or connector and configured to receive the sensor, said sensor entry port being defined by a wall, and

a locating notch extending from said wall, said locating notch configured to receive a complementary locating tooth from the sensor, the interconnection of said notch and a tooth preventing rotational movement of the sensor within said sensor entry port.

29. A breathing circuit component or connector as claimed in claim 28, further comprising a sensor mounted within said sensor entry port.