METHOD OF DETECTING ERRORS IN THE CONNECTIONS IN A HUMIDIFICATION SYSTEM

• US 20190307978A1
• Filed: 10/11/2017
• Published: 10/10/2019
• Est. Priority Date: 10/11/2016
• Status: Active Grant

• Current Assignee: Fisher & Paykel Healthcare Limited
• Original Assignee: Fisher & Paykel Healthcare Limited
• Inventors: Liu, Po-Yen, Teng, Ivan Chih-Fan, Seekup, Peter Alan, Smith, Daniel John, Lo, Ho Shing
• Granted Patent: US 11,684,736 B2
• Time in Patent Office: Days
• CPC Class Codes: A61M 16/0051 with alarm devices
• CPC Class Codes: A61M 16/022 Control means therefor
• CPC Class Codes: A61M 16/026 specially adapted for predicting, e.g. for determining an information representative of a flow limitation during a ventilation cycle by using a root square technique or a regression analysis
• CPC Class Codes: A61M 16/109 the humidifying liquid or the beneficial agent
• CPC Class Codes: A61M 16/16 Devices to humidify the respiration air A61M16/1045 takes precedence
• CPC Class Codes: A61M 2205/14 Detection of the presence or absence of a tube, a connector or a container in an apparatus
• CPC Class Codes: A61M 2205/18 with alarm
• CPC Class Codes: A61M 2205/3368 Temperature
• CPC Class Codes: A61M 2205/502 User interfaces, e.g. screens or keyboards
• CPC Class Codes: A61M 2205/581 by audible feedback
• CPC Class Codes: A61M 2205/583 by visual feedback
• CPC Class Codes: A61M 2205/70 with testing or calibration facilities

Abstract

Various control methods can indirectly determine incorrect connections between components in a respiratory therapy system. For example, errors in the connections can occur between a patient interface, a humidifier and/or a gases source. The methods can indirectly detect if a reverse flow condition exists or other error conditions. A reverse flow condition can occur when gases flows in a direction different from an intended direction of flow. The detection of the reverse flow condition can be indicative of likely errors in connections between the humidifier, patient interface and/or gases source.

Claims

1. A method of detecting incorrect connections in a respiratory humidification system comprising a gases source, a humidifier including an inlet and an outlet, and an inspiratory conduit, the method comprising:

performing one or more reverse flow detection tests by comparing an inlet temperature measured by a sensor at the inlet of the humidifier with one or more of an outlet set point or an outlet temperature measurement measured by a sensor positioned at the outlet of the humidifier; and

outputting an indication of reverse flow conditions indicative of the incorrect connections when the inlet temperature is higher than one or more of the outlet set point or the outlet temperature measurement.

29. The method of any of claim 1, 3-5, 9, 11, 13, 15, 17, 19, 21-22, or 27, further comprising alerting a user of the indication of reverse flow conditions.

30. The method of claim 29, wherein alerting comprises providing one or more audible alarms, text message, images, or a combination thereof.

31. The method of claim 29 or 30, wherein alerting comprises providing instructions for resolving the reverse flow conditions.

32. The method of any of claim 1, 3-5, 9, 11, 13, 15, 17, 19, 21-22, 27, or 29-31, wherein the humidification system comprises an expiratory conduit.

34. The humidification system of claim 32, wherein the alert comprises one or more audible alarms, text message, images, or a combination thereof.

35. The humidification system of claim 32 or 33, wherein the alert comprises instructions for resolving the reverse flow conditions.

2. A respiratory humidification system with incorrect connection detection, the system comprising:

a gases source configured to provide a source of gases;

a humidifier including an inlet and an outlet, the humidifier configured to humidify air and further including a humidifier heat source to heat a liquid to humidify the gases provided by the gases source;

an inspiratory conduit configured to provide the humidified gases to a user, the gases source, humidifier and inspiratory conduit forming at least a part of a breathing circuit;

sensors at the humidifier inlet and outlet configured to measure an inlet temperature and an outlet temperature, respectively; and

a hardware and/or software controller, the hardware and/or software controller in electrical communication with the sensors, the hardware and/or software controller configured to output an indication of reverse flow conditions indicative of the incorrect connections when the inlet temperature is higher than one or more of an outlet set point or the outlet temperature.

3. A method of detecting reverse flow in a respiratory humidification system comprising a gases source, a humidifier including an inlet and an outlet, and an inspiratory conduit, the method comprising:

performing one or more reverse flow detection tests by comparing an inlet parameter measured by a first sensor at the inlet of the humidifier with an outlet parameter measured by a second sensor at the outlet of the humidifier; and

outputting an indication of reverse flow conditions when the inlet parameter is higher than the outlet parameter.

4. The method of claim 3, wherein the parameter comprises a flow rate.

5. The method of claim 3, wherein the parameter comprises a power dissipation value.

6. A respiratory humidification system with reverse flow detection, the system comprising:

a gases source configured to provide a source of gases;

a humidifier including an inlet and an outlet, the humidifier configured to humidify air and further including a humidifier heat source to heat a liquid to humidify the gases provided by the gases source;

an inspiratory conduit configured to provide the humidified gases to a user, the gases source, humidifier and inspiratory conduit forming at least a part of a breathing circuit;

sensors at the humidifier inlet and outlet and configured to measure an inlet parameter and an outlet parameter, respectively; and

a hardware and/or software controller, the hardware and/or software controller in electrical communication with the sensors, the hardware and/or software controller configured to output an indication of reverse flow conditions when the inlet parameter is higher than the outlet parameter.

7. The respiratory humidification system of claim 6, wherein the parameter comprises a flow rate.

8. The respiratory humidification system of claim 6, wherein the parameter comprises a power dissipation value.

9. A method of detecting incorrect connections in a respiratory humidification system comprising a gases source, a humidifier including an inlet and an outlet, and an inspiratory conduit, the method comprising:

performing one or more reverse flow detection tests by a hardware and/or software controller of the humidification system, the one or more reverse flow detection tests including the steps of;

comparing a patient end temperature measured by a first sensor at a patient end of the inspiratory conduit of the humidification system with a patient end set point;

when the patient end temperature is higher than the patient end set point, comparing an inlet temperature measured by a second sensor at the inlet of the humidifier of the humidification system with an outlet set point or an outlet temperature measured by a third sensor at the outlet of the humidifier; and

outputting an indication of reverse flow conditions indicative of the incorrect connections when the inlet temperature is higher than the outlet set point or the outlet temperature.

11. The method of claim 9, further comprising comparing the inlet temperature with an ambient temperature when the inlet temperature is higher than the outlet set point or the outlet temperature, and outputting the indication of reverse flow conditions when the inlet temperature is higher than the ambient temperature.

10. A respiratory humidification system with incorrect connection detection, the system comprising:

a gases source configured to provide a source of gases;

a humidifier including an inlet and an outlet, the humidifier configured to humidify air and further including a humidifier heat source to heat a liquid to humidify the gases provided by the gases source;

an inspiratory conduit configured to provide the humidified gases to a user, the gases source, humidifier and inspiratory conduit forming at least a part of a breathing circuit;

a first sensor at a patient end of the inspiratory conduit and configured to measure a patient end temperature;

a second sensor at the humidifier inlet and configured to measure an inlet temperature;

a third sensor at the humidifier outlet and configured to measure an outlet temperature; and

a hardware and/or software controller, the hardware and/or software controller in electrical communication with the first, second and third sensors, the hardware and/or software controller configured to detect an indication of reverse flow conditions indicative of the incorrect connections in the humidification system by;

comparing the inlet temperature with an outlet set point or the outlet temperature when the patient end temperature is higher than the patient end set point, and

outputting an indication of reverse flow conditions when the inlet temperature is higher than the outlet set point or the outlet temperature.

12. The respiratory humidification system of claim 10, wherein the hardware and/or software controller is further configured to compare the inlet temperature with an ambient temperature when the inlet temperature is higher than the outlet set point or the outlet temperature, and to output the indication of reverse flow conditions when the inlet temperature is higher than the ambient temperature.

33. The humidification system of any of claim 2, 6-8, 10, 12, 14, 16, 18, 20, 23-26, or 28, wherein the hardware and/or software controller is configured to alert the user of the indication of reverse flow conditions.

36. The humidification system of any of claim 2, 6-8, 10, 12, 14, 16, 18, 23-26, 20, 28, or 33-35, further comprising an expiratory conduit.

13. A method of detecting reverse flow in a respiratory humidification system comprising a gases source, a humidifier including an inlet and an outlet, and an inspiratory conduit, the method comprising:

performing one or more reverse flow detection tests by a hardware and/or software controller of the humidification system, the one or more reverse flow detection tests including the steps of;

comparing a patient end temperature measured by a first sensor at a patient end of the inspiratory conduit of the humidification system with a patient end set point;

when the patient end temperature is lower than the patient end set point, comparing an outlet temperature measured by a second sensor at the outlet of the humidifier of the humidification system with the patient end temperature; and

outputting an indication of reverse flow conditions when the outlet temperature is higher than the patient end temperature.

14. A respiratory humidification system with reverse flow detection, the system comprising:

a gases source configured to provide a source of gases;

a humidifier including an inlet and an outlet, the humidifier configured to humidify air and further including a humidifier heat source to heat a liquid to humidify the gases provided by the gases source;

an inspiratory conduit configured to provide the humidified gases to a user, the gases source, humidifier and inspiratory conduit forming at least a part of a breathing circuit;

a first sensor at a patient end of the inspiratory conduit and configured to measure a patient end temperature;

a second sensor at the humidifier outlet and configured to measure an outlet temperature; and

a hardware and/or software controller, the hardware and/or software controller in electrical communication with the first and second sensors, the hardware and/or software controller configured to detect an indication of reverse flow conditions in the humidification system by;

comparing the outlet temperature with the patient end temperature when the patient end temperature is lower than the patient end set point; and

outputting an indication of reverse flow conditions when the outlet temperature is higher than the patient end temperature.

15. A method of detecting incorrect connections in a respiratory humidification system comprising a gases source, a humidifier including an inlet and an outlet, and an inspiratory conduit, the method comprising:

providing a first electrical power to a humidifier heat source in the humidifier of the humidification system;

comparing an inlet temperature measured by a first sensor at the inlet of the humidifier of the humidification system with an outlet temperature measured by a second sensor at the outlet of the humidifier, or a change in the inlet temperature with a change in the outlet temperature; and

outputting an indication of reverse flow conditions indicative of the incorrect connections when the inlet temperature is higher than the outlet temperature or when the change in the inlet temperature is greater than the change in the outlet temperature.

19. The method of any of claim 15 or 17, wherein the first electrical power is a maximum electrical power.

27. The method of any of claim 15, 17, 19, or 21-22, further comprising interrupting a therapy that is run on the humidification system, the therapy being a respiratory or ventilation therapy and/or a humidification therapy.

16. A respiratory humidification system with incorrect connection detection, the system comprising:

a gases source configured to provide a source of gases;

a humidifier including an inlet and an outlet, the humidifier configured to humidify air and further including a humidifier heat source to heat a liquid to humidify the gases provided by the gases source;

an inspiratory conduit configured to provide the humidified gases to a user, the gases source, humidifier and inspiratory conduit forming at least a part of a breathing circuit;

a first sensor at the humidifier inlet and configured to measure an inlet temperature;

a second sensor at the humidifier outlet and configured to measure an outlet temperature; and

a hardware and/or software controller, the hardware and/or software controller in electrical communication with the first and second sensors, the hardware and/or software controller configured to detect an indication of reverse flow conditions indicative of the incorrect connections in the humidification system by;

provide a first electrical power to the humidifier heat source, and

outputting an indication of reverse flow conditions when the inlet temperature is higher than the outlet temperature or when the change in the inlet temperature is greater than the change in the outlet temperature.

20. The humidification system of any of claim 16 or 18, wherein the first electrical power is a maximum electrical power.

28. The humidification system of any of claim 16, 18, 20, or 23-26, wherein the hardware and/or software controller is configured to interrupt a therapy that is run on the humidification system when indicating reverse flow conditions in the humidification system, the therapy being a respiratory or ventilation therapy or a humidification therapy.

17. A method of detecting reverse flow in a respiratory humidification system comprising a gases source, a humidifier including an inlet and an outlet, and an inspiratory conduit, the method comprising:

providing a first electrical power to an inspiratory conduit heat source in the inspiratory conduit of the humidification system;

comparing a patient end temperature measured by a first sensor at a patient end of the inspiratory conduit with an outlet temperature measured by a second sensor at the outlet of the humidifier of the humidification system, or a change in the patient end temperature with a change in the outlet temperature; and

outputting an indication of reverse flow conditions when the patient end temperature is lower than the outlet temperature or when the change in the patient end temperature is less than the change in the outlet temperature.

18. A respiratory humidification system with reverse flow detection, the system comprising:

a gases source configured to provide a source of gases;

a humidifier including an inlet and an outlet, the humidifier configured to humidify air and further including a humidifier heat source to heat a liquid to humidify the gases provided by the gases source;

an inspiratory conduit configured to provide the humidified gases to a user and including an inspiratory conduit heat source, the gases source, humidifier and inspiratory conduit forming at least a part of a breathing circuit;

a first sensor at a patient end of the inspiratory conduit and configured to measure a patient end temperature;

a second sensor at the humidifier outlet and configured to measure an outlet temperature; and

a hardware and/or software controller, the hardware and/or software controller in electrical communication with the first and second sensors, the hardware and/or software controller configured to detect an indication of reverse flow conditions in the humidification system by;

provide a first electrical power to the inspiratory conduit heat source, and

output an indication of reverse flow conditions when the patient end temperature is lower than the outlet temperature or when the change in the patient end temperature is less than the change in the outlet temperature.

21. A method of detecting reverse flow in a respiratory humidification system, the method comprising:

using one or more hardware processors of the humidification system to control circuitry configured to power a heating element, providing electrical power to the heating element of the humidification system, the humidification system further comprising a gases source, a humidifier including an inlet and an outlet, and an inspiratory conduit including an inspiratory conduit heat source, the humidifier further including a humidifier heat source;

comparing a first temperature gradient measured by a first sensor downstream of the heating element with a second temperature gradient measured by a second sensor upstream of the heating element, the first and second sensors in electrical communication with the one or more hardware processors; and

outputting to a display of the humidification system an indication of reverse flow conditions when the second temperature gradient is higher than the first temperature gradient.

22. The method of claim 21, further comprising:

providing another electrical power to the humidifier heat source of the humidifier of the humidification system;

receiving sensor data from a humidifier heat source temperature sensor at or near the humidifier heat source, the humidifier heat source temperature sensor in electrical communication with the one or more hardware processors;

comparing a temperature gradient at the humidifier heat source with a threshold temperature gradient; and

outputting to the display of the humidification system an indication of humidifier water-out condition when the temperature gradient at the humidifier heat source is higher than the threshold temperature gradient.

23. A respiratory humidification system with reverse flow detection, the system comprising:

a gases source configured to provide a source of gases;

a humidifier including an inlet and an outlet, the humidifier configured to humidify air and further including a humidifier heat source to heat a liquid to humidify the gases provided by the gases source;

an inspiratory conduit configured to provide the humidified gases to a user and including an inspiratory conduit heat source, the gases source, humidifier and inspiratory conduit forming at least a part of a breathing circuit;

a first sensor downstream of the humidifier heat source and/or the inspiratory conduit heat source and configured to measure a first temperature;

a second sensor upstream of the humidifier heat source and/or the inspiratory conduit heat source and configured to measure a second temperature; and

a hardware and/or software controller, the hardware and/or software controller in electrical communication with the first and second sensors, the hardware and/or software controller configured to detect an indication of reverse flow conditions in the humidification system by;

providing an electrical power to the humidifier heat source and/or the inspiratory conduit heat source;

comparing a first temperature gradient at the first sensor with a second temperature gradient at the second sensor; and

outputting an indication of reverse flow conditions when the second temperature gradient is higher than the first temperature gradient.

24. The system of claim 23, wherein the hardware and/or software controller is further configured to detect a humidifier water-out condition by:

providing another electrical power to the humidifier heat source;

receiving sensor data from a humidifier heat source temperature sensor at or near the humidifier heat source, the humidifier heat source temperature sensor in electrical communication with the one or more hardware processors;

comparing a temperature gradient at the humidifier heat source with a threshold temperature gradient; and

outputting an indication of humidifier water-out condition when the temperature gradient at the humidifier heat source is higher than the threshold temperature gradient.

25. The system of claim 23 or 24, wherein the first sensor is located at the humidifier outlet or the humidifier inlet.

26. The system of any of claims 23-25, wherein the second sensor is located at a patient end of the inspiratory conduit or the humidifier outlet.

37. A method of detecting disconnection of an expiratory conduit heat source in a dual-limb respiratory humidification system, the system comprising an expiratory conduit having the expiratory conduit heat source, an inspiratory conduit having a segmented inspiratory conduit heat source, a first heat source driver configured to energize the expiratory conduit heat source and at least a segment of the inspiratory conduit heat source, and a second heat source driver configured to energize the expiratory conduit heat source and at least another segment of the inspiratory conduit heat source, the method comprising:

using one of the first and second heat source drivers, providing a voltage across the expiratory and inspiratory conduit heat sources;

monitoring a current detected by the one of the first and second heat source drivers; and

outputting an indication of inspiratory conduit heat source disconnection when the current deviates from an expected value by a predetermined tolerance, or shows a change above or below a threshold.

38. The method of claim 37, further comprising:

exiting an ongoing therapy mode;

reconnecting the first and second heat source drivers so that one of the first and second drivers is configured to energize the expiratory conduit heat source and another one of the first and second drivers is configured to energize the inspiratory conduit heat source;

using the one of the first and second heat source drivers, providing a second voltage across the expiratory conduit heat source;

monitoring a current detected by the one of the first and second heat source drivers; and

outputting an indication of expiratory conduit heat source disconnection when the current is at or near zero.

40. The method of any of claims 37-39, wherein activation of the method is configured to be adjustable.

39. The method of 38, wherein the second voltage comprises a low duty cycle or a minimum power.

41. A dual-limb respiratory humidification system with expiratory conduit heat source disconnection detection, the system comprising:

a breathing circuit having a gases source configured to provide a source of gases, a humidifier configured to heat a liquid to humidify the gases provided by the gases source, an inspiratory conduit configured to provide the humidified gases to a user from the humidifier and including a segmented inspiratory conduit heat source, and an expiratory conduit configured to provide exhaled gases from the user to the gases source and including an expiratory conduit heat source;

a first heat source driver configured to energize the expiratory conduit heat source and at least a segment of the inspiratory conduit heat source; and

a second heat source driver configured to energize the expiratory conduit heat source and at least another segment of the inspiratory conduit heat source,

wherein at least one of the first and second heat source drivers is configured to detect an indication of expiratory conduit heat source disconnection by;

providing a voltage across the expiratory and inspiratory conduit heat sources;

detecting a current; and

outputting an indication of inspiratory conduit heat source disconnection when the current deviates from an expected value by a predetermined tolerance, or shows a sudden change above or below a threshold.

42. The system of claim 41, wherein the system is configured to switch configurations of the first and second heat source drivers so that one of the first and second drivers is configured to energize the expiratory conduit heat source and another one of the first and second drivers is configured to energize the inspiratory conduit heat source, the one of the first and second drivers configured to:

provide a second voltage across the expiratory conduit heat source;

detected a current; and

outputting an indication of expiratory conduit heat source disconnection when the current is at or near zero.

43. The system of claim 42, wherein the second voltage comprises a low duty cycle or a minimum power.

44. The system of any of claims 41-43, wherein the system is configured to detect an indication of expiratory conduit heat source disconnection at adjustable intervals.

45. A method of detecting disconnection of an expiratory conduit heat source in a dual-limb respiratory humidification system, the system comprising an expiratory conduit having the expiratory conduit heat source, an inspiratory conduit having an inspiratory conduit heat source, a first heat source driver configured to energize the expiratory conduit heat source, and a second heat source driver configured to energize the inspiratory conduit heat source, the method comprising:

using the first heat source driver, providing a voltage across the expiratory conduit heat source;

monitoring a current detected by the first heat source driver; and

outputting an indication of expiratory conduit heat source disconnection when the current is at or near zero.

46. A dual-limb respiratory humidification system with expiratory conduit heat source disconnection detection, the system comprising:

a breathing circuit having a gases source configured to provide a source of gases, a humidifier configured to heat a liquid to humidify the gases provided by the gases source, an inspiratory conduit configured to provide the humidified gases to a user from the humidifier and including an inspiratory conduit heat source, and an expiratory conduit configured to provide exhaled gases from the user to the gases source and including an expiratory conduit heat source;

a first heat source driver configured to energize the expiratory conduit heat source; and

a second heat source driver configured to energize the inspiratory conduit heat source,

wherein the first heat source driver is configured to detect an indication of expiratory conduit heat source disconnection by;

provide a voltage across the expiratory conduit heat source;

detected a current; and

outputting an indication of expiratory conduit heat source disconnection when the current is at or near zero.

47. A method of detecting reverse flow in a respiratory humidification system using transient system parameters, the respiratory humidification system comprising a gases source, a humidifier including an inlet and an outlet, an inspiratory conduit, and a plurality of sensors, the method comprising:

receiving inputs from one or more of the plurality of sensors and/or system parameters of the respiratory humidification system;

determining a reverse flow prediction indicator based at least in part on the inputs and/or system parameters;

outputting an indication of reverse flow conditions when the reverse flow prediction indicator exceeds zero.

49. The method of claim 47 or the humidification system of claim 48, wherein the plurality of sensors comprise more than one of a humidifier inlet temperature and/or flow rate sensor, a humidifier outlet temperature and/or flow rate sensor, a patient end temperature sensor, and/or a humidifier heat source temperature sensor.

50. The method of claim 47 or 49, or the humidification system of claim 48 or 49, wherein the system parameters comprise more than one of a humidifier heat source power, a humidifier outlet set point temperature, a patient end set point temperature, and/or power of at least a segment of an inspiratory conduit heat source.

51. The method of claim 47 or 49-50, or the humidification system of claim 48 or 49-50, wherein the reverse flow prediction indicator is determined based at least in part on more than one parameter.

52. The method of claim 47 or 50, or the humidification system of claim 48 or 50, wherein the reverse flow prediction indicator is determined at least in part on a humidifier inlet temperature, an absolute value of a difference between a humidifier outlet temperature and a humidifier outlet set point, a ratio of a flow rate to a humidifier heat source power, a ratio of the humidifier inlet temperature to the humidifier outlet set point, and a ratio of the humidifier inlet temperature to a tube temperature.

53. The method of claim 47 or 50, or the humidification system of claim 48 or 50, wherein the reverse flow prediction indicator is determined at least in part on a filtered or unfiltered flow rate, an absolute value of a difference between a humidifier outlet temperature and a humidifier outlet set point, a ratio of a humidifier inlet temperature to a tube temperature, and a ratio of a filtered or unfiltered power of a segment of an inspiratory conduit heat source to a humidifier heat source temperature.

54. The method of any of claim 47 or 49-53, or the humidification system of any of claim 48 or 48-53, wherein the received inputs are from a transient state or steady state.

48. A respiratory humidification system with reverse flow detection, the system comprising:

a gases source configured to provide a source of gases;

a humidifier including an inlet and an outlet, the humidifier configured to humidify air and further including a humidifier heat source to heat a liquid to humidify the gases provided by the gases source;

an inspiratory conduit configured to provide the humidified gases to a user, the gases source, humidifier and inspiratory conduit forming at least a part of a breathing circuit;

a plurality of sensors; and

a hardware and/or software controller, the hardware and/or software controller in electrical communication with the plurality of sensors, the hardware and/or software controller configured to detect an indication of reverse flow conditions in the humidification system by;

receiving inputs from one or more of the plurality of sensors and/or system parameters of the respiratory humidification system;

determining a reverse flow prediction indicator based at least in part on the inputs and/or system parameters;

outputting an indication of reverse flow conditions when the reverse flow prediction indicator exceeds zero.