METHOD OF USING A TEMPERATURE-BASED AEROSOL DETECTOR

• US 20120285236A1
• Filed: 12/14/2010
• Published: 11/15/2012
• Est. Priority Date: 01/20/2010
• Status: Abandoned Application

• Current Assignee: Koninklijke Philips N.V.
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Denyer, Jonathan Stanley Harold, Leppard, Michael James Robbert, Dyche, Anthony, Dekker, Ronald, Marcelis, Bout, Haartsen, Jacob Roger
• Application Number:
  US13/574,117
• Publication Number:
  US 20120285236A1
• Time in Patent Office: Days
• US Class Current: 73/204.11
• CPC Class Codes: A61M 11/005 using ultrasonics spraying or atomising liquids using ultrasonic vibrations in general B05B17/06
• CPC Class Codes: A61M 11/06 of the injector type
• CPC Class Codes: A61M 15/0065 Inhalators with dosage or measuring devices A61M15/0028 takes precedence; dosage devices incorporated in aerosol cans B65D83/52
• CPC Class Codes: A61M 15/008 Electronic counters
• CPC Class Codes: A61M 15/0086 Inhalation chambers
• CPC Class Codes: A61M 15/009 using medicine packages with incorporated spraying means, e.g. aerosol cans pocket atomiser of the injector type A61M11/08
• CPC Class Codes: A61M 2205/3368 Temperature
• CPC Class Codes: A61M 2205/502 User interfaces, e.g. screens or keyboards
• CPC Class Codes: A61M 2205/52 with memories providing a history of measured variating parameters of apparatus or patient
• CPC Class Codes: A61M 2205/581 by audible feedback
• CPC Class Codes: A61M 2205/582 by tactile feedback
• CPC Class Codes: A61M 2205/583 by visual feedback
• CPC Class Codes: G01F 1/684 Structural arrangements; Mounting of elements, e.g. in relation to fluid flow
• CPC Class Codes: G01F 1/6888 Thermoelectric elements, e.g. thermocouples, thermopiles

Abstract

An aerosol delivery system (e.g., MDI or nebulizer for delivering aerosolized medication to a patient) includes a temperature sensor in an aerosol output pathway of the system. A controller determines that an aerosol generator of the system has released aerosol when the sensor senses a predetermined temperature change in the pathway. The temperature sensor may also comprise a thermal flow sensor that includes a heater and upstream and downstream temperature sensors. The controller compares the upstream and downstream temperatures to determine the presence, direction, and/or magnitude of fluid flow in the pathway. The controller may use the aerosol detection and/or flow detection to monitor compliance with desired use of the system and/or provide real-time instructions to a user for proper use of the system. The controller may record the aerosolization and flow data for later analysis.

Claims

1. A method of detecting the presence of aerosol in a pathway, the method comprising:

sensing a temperature of the fluid pathway; and

determining from the sensed temperature whether aerosol is present in the pathway.

2. The method of claim 1, wherein:

the pathway comprises a pathway of an aerosol delivery system that further includes an aerosol generator and an aerosol output opening, wherein the fluid pathway extends between and fluidly connects the aerosol generator and the aerosol output opening, and

the method further comprises aerosolizing a fluid using the aerosol generator.

3. The method of claim 2, wherein the output opening comprises a patient interface that is constructed and arranged to direct aerosol generated by the aerosol generator into a patient'"'"'s airway.

4. The method of claim 2, wherein:

the system comprises a metered-dose inhaler, and

said aerosolizing of the fluid comprises releasing a bolus of aerosol from a pressurized canister.

5. The method of claim 4, further comprising using the temperature signal to detect a release of a bolus of aerosol from the metered-dose inhaler.

6. The method of claim 5, further comprising indicating, via a bolus release indicator, the release of a bolus of aerosol based on said detection of a release of a bolus of aerosol.

7. The method of claim 5, further comprising using the temperature signal to count the number of boluses released from the metered-dose inhaler, and recording the counted number in a memory.

8. The method of claim 7, further comprising displaying on a display the counted number of boluses released from the metered-dose inhaler.

9. The method of claim 2, further comprising providing an indication to a user of the system in response to the detection of aerosol in the pathway.

10. The method of claim 9, wherein providing the indication comprises one of providing a visual indication, providing an audible indication, or providing a haptic indication.

11. The method of claim 2, wherein:

the system comprises a nebulizer that includes a container for storing liquid to be aerosolized,

aerosolizing a fluid using the aerosol generator comprises aerosolizing liquid from the container, and

the method further comprises using the temperature signal to detect when the aerosol generator is aerosolizing liquid from the container.

12. The method of claim 11, further comprising:

using the temperature signal to determine a duration during which the aerosol generator aerosolizes liquid from the container, and

recording the determined length of time in a memory.

13. The method of claim 12, further comprising detecting when, based on the absence of aerosol in the fluid pathway, the aerosol generator has stopped aerosolizing liquid from the container.

14. The method of claim 13, further comprising using the temperature signal to detect when liquid in the container has run dry.

15. The method of claim 14, further comprising providing an indication that the container has run dry in response to the detection that the container has run dry.

16. The method of claim 1, wherein sensing the temperature of the fluid pathway comprises sensing the temperature using a thermocouple having a reference junction and a sensing junction, wherein the sensing junction is disposed at a location whose temperature tracks a temperature of the pathway more quickly than a location of the reference junction.

17. The method of claim 16, further comprising determining that aerosol is present when a temperature signal of the thermocouple indicates that a temperature at the sensing junction is colder than a temperature at the reference junction by a predetermined threshold difference.

18. The method of claim 1, further comprising determining that aerosol is present in the pathway when the temperature signal varies by more than a predetermined temperature differential within a predetermined amount of time.

19. The method of claim 18, wherein:

the thermocouple is part of a temperature sensor,

the temperature sensor comprises a silicon frame and a membrane connected to the silicon frame,

the silicon frame and membrane are disposed in the pathway,

the silicon frame has a higher thermal capacitance than the membrane,

the first junction is disposed in a location that senses the temperature of the membrane, and

the second junction is disposed in a location that senses the temperature of the silicon frame.

20. The method of claim 1, wherein determining from the sensed temperature whether aerosol is present in the pathway comprises:

determining a baseline temperature when the controller is turned on, and

determining that aerosol is present when the sensed temperature deviates from the baseline temperature by more than a predetermined threshold.

21. The method of claim 1, wherein sensing the temperature of the fluid pathway comprises sensing the temperature using a temperature sensor that includes:

a frame,

a membrane connected to the frame, and

a temperature-sensitive resistor disposed on the membrane to sense a temperature of the membrane,

wherein the membrane is disposed in the pathway,

wherein the frame has a higher thermal capacitance than the membrane, and

wherein sensing the temperature comprises sensing a resistance of the resistor.

22. The method of claim 1, wherein the pathway includes:

an air space extending from the aerosol generator to the aerosol output opening, and

walls defining the air space.

23. The method of claim 1, wherein the temperature is sensed in terms of a unit of measurement that is correlated to temperature.