Systems and methods of detecting incorrect connections in a humidification system

A method of detecting reverse flow condition in a respiratory humidification system including a gases source, a controller, a humidifier, and a breathing circuit, the method comprising:

• using the controller of the humidification system:
• measuring an outlet temperature using a sensor at or near an outlet of a chamber of the humidifier;
• and
• in response to detecting at least two trigger events, outputting an indication of a reverse flow condition,
• wherein a trigger event comprises the chamber outlet temperature reaching a first threshold temperature.

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

• using the controller of the humidification system:
• determining a first patient end temperature at or near a patient end of the inspiratory conduit and/or a first outlet temperature at or near the outlet of the humidifier;
• providing an electrical power to an inspiratory conduit heat source in the inspiratory conduit;
• determining a second patient end temperature at or near the patient end of the inspiratory conduit and a second outlet temperature at or near the outlet of the humidifier after providing the electrical power to the inspiratory conduit heat source;
• comparing the first patient end temperature with the second patient end temperature and/or comparing the first outlet temperature with the second outlet temperature;
• in response to the second patient end temperature being greater than the first patient end temperature and/or the second outlet temperature being greater than the first outlet temperature, comparing at least one of:
• the second patient end temperature with the second outlet temperature;
• a change in the second patient end temperature with a change in the second outlet temperature over an associated predetermined time period;
• the second patient end temperature with a patient end temperature threshold;
• the second outlet temperature with an outlet temperature threshold;
• a rate of change in the second patient end temperature with a second patient end temperature rate of change threshold
• a rate of change in the second outlet temperature with a second outlet temperature rate of change threshold;
• and/or
• a rate of change in the second patient end temperature with a rate of change in the second outlet temperature over an associated predetermined time period;
• and
• outputting an indication of reverse flow conditions in response to at least one of:
• the second patient end temperature being lower than the second outlet temperature,
• the change in the second patient end temperature being lower than the change in the second outlet temperature over the associated predetermined time period,
• the second patient end temperature being lower than the patient end temperature threshold,
• the second outlet temperature being higher than the outlet temperature threshold,
• the rate of change in the second patient end temperature being higher than the second patient end temperature rate of change threshold,
• the rate of change in the second outlet temperature being higher than the second outlet temperature rate of change threshold, and/or
• the rate of change in the second patient end temperature being lower than the rate of change in the second outlet temperature over the associated predetermined time period.

A reverse flow detector of a respiratory humidification system, the detector comprising:

• a controller configured to be in electrical communication with a first sensor and a second sensor, wherein the first sensor is at or near a patient end of an inspiratory conduit and configured to measure a patient end temperature, and the second sensor is at or near an outlet of a humidifier and configured to measure an outlet temperature, the inspiratory conduit configured to provide humidified gases to a user and including an inspiratory conduit heat source, the humidifier configured to humidify gases and further including a humidifier heat source to heat a liquid to humidify the gases provided by a gases source;
• the controller configured to detect an indication of reverse flow conditions in the humidification system by being configured to:
• determine a first patient end temperature at a patient end of the inspiratory conduit and/or a first outlet temperature at the outlet of the humidifier;
• provide an electrical power to the inspiratory conduit heat source;
• determine a second patient end temperature and a second outlet temperature after providing the electrical power to the inspiratory conduit heat source;
• compare the first patient end temperature with the second patient end temperature and/or compare the first outlet temperature with the second outlet temperature;
• in response to the second patient end temperature being greater than the first patient end temperature and/or the second outlet temperature being greater than the first outlet temperature, compare at least one of:
• the second patient end temperature with the second outlet temperature;
• a change in the second patient end temperature with a change in the second outlet temperature over an associated predetermined time period;
• the second patient end temperature with a patient end temperature threshold;
• the second outlet temperature with an outlet temperature threshold;
• a rate of change in the second patient end temperature with a patient end temperature rate of change threshold;
• a rate of change in the second outlet temperature with a outlet temperature rate of change threshold;
• and/or
• a rate of change in the second patient end temperature with a rate of change in the second outlet temperature over an associated predetermined time period;
• and
• output an indication of reverse flow conditions in response to at least one of:
• the second patient end temperature being lower than the second outlet temperature,
• the change in the second patient end temperature being lower than the change in the second outlet temperature over the associated predetermined time period,
• the second patient end temperature being lower than the patient end temperature threshold,
• the second outlet temperature being higher than the outlet temperature threshold,
• the rate of change in the second patient end temperature is higher than the patient end temperature rate of change threshold,
• the rate of change in the second outlet temperature is higher than the outlet temperature rate of change threshold, and/or
• the rate of change in the second patient end temperature being lower than the rate of change in the second outlet temperature over the associated predetermined time period.

A reverse flow detector of a respiratory humidification system, the detector comprising:

• a controller configured to be in electrical communication with a first sensor and a second sensor, wherein the first sensor is at or near a patient end of an inspiratory conduit and configured to measure a patient end temperature, and the second sensor is at or near an outlet of a humidifier and configured to measure an outlet temperature, the inspiratory conduit configured to provide humidified gases to a user and including an inspiratory conduit heat source, the humidifier configured to humidify gases and further including a humidifier heat source to heat a liquid to humidify the gases provided by a gases source;
• the controller configured to detect an indication of reverse flow conditions in the humidification system by being configured to:
• provide an electrical power to an inspiratory conduit heat source in the inspiratory conduit for a predetermined period of time;
• determine a patient end temperature at or near a patient end of the inspiratory conduit and a chamber outlet temperature at or near the outlet of the humidifier after providing the electrical power to the inspiratory conduit heat source for the predetermined period of time;
• and
• output an indication of reverse flow conditions in response to at least one of:
• a comparison of the patient end temperature to one or more patient end temperature thresholds,
• a comparison of the chamber outlet temperature to one or more chamber outlet temperature thresholds,
• a comparison of the patient end temperature to a chamber outlet temperature.

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

• using a controller of the system:
• receiving inputs from one or more of the plurality of sensors;
• determining that the inputs are at steady state;
• calculating a reverse flow indicator based at least in part on at least some of the inputs;
• and
• outputting an indication of a reverse flow condition in response to the reverse flow indicator exceeding a threshold.

A reverse flow detector of a respiratory humidification system that includes a gases source, a humidifier including an inlet and an outlet, an inspiratory conduit, and a plurality of sensors, the detector comprising:

• a controller in electrical communication with the plurality of sensors, wherein the controller is configured to:
• receive inputs from one or more of the plurality of sensors;
• determine that the inputs are at steady state;
• calculate a reverse flow indicator based at least in part on at least some of the inputs;
• and
• output an indication of reverse flow conditions in response to the reverse flow indicator exceeds a threshold.