A nasal cannula interface is provided for a respiratory support system configured to receive a breathable gases flow, the nasal cannula interface comprising: a. an inlet to receive the gases flow; b. at least one nasal prong configured to receive the gases flow from the inlet, and to be received in, and to deliver the gases flow to, a nare of the patient. The nasal cannula interface may comprise one or more structural features that are configured to help manage, avoid and/or reduce generation of aerosols by the patient during breathing and/or whilst breathing gases from a respiratory support apparatus.

A breathable gas inlet control device permits flow regulation at the inlet of a flow generator for a respiratory treatment apparatus such as a ventilator or continuous positive airway pressure device. The device may implement a variable inlet aperture size based on flow conditions. In one embodiment, an inlet flow seal opens or closes the inlet to a blower in accordance with changes in pressure within a seal activation chamber near the seal. The seal may be formed by a flexible membrane. A controller selectively changes the pressure of the seal activation chamber by controlling a set of one or more flow control valves to selectively stop forward flow, prevent back flow or lock open the seal to permit either back flow or forward flow. The controller may set the flow control valves as a function of detected respiratory conditions based on data from pressure and/or flow sensors.

A respiratory flow therapy apparatus including a sensing chamber which measures a flow of gases provided to a patient. The sensing chamber can be located after a blower and/or mixer. The sensing chamber can include an ultrasonic transducer, a temperature sensor, a heated temperature sensing element, and/or a gas concentration sensor. A flow path of gases used in conjunction with the sensor system prevents unwanted vorticity in the flow of gases that can create anomalies in measuring flow.

In an example, a ventilator includes a first container and a second container in fluidic communication with each other via a liquid. The second container includes a second container space surrounded by the second container and a second liquid surface. A hydrostatic pressure in the second container space results from a pressure differential defined by a difference between the first liquid surface elevation in the first container and the second liquid surface elevation. The second container space increases in size with an increase in the breathing gas supplied from a gas supply line to the second container space. An inhalation line is configured to open to permit a flow of the breathing gas from an inhalation inlet in the second container space to an inhalation outlet outside of the liquid and outside of the second container and coupled to a patient, causing the second container space to decrease in size.

Systems and methods for generating nitric oxide are disclosed. A nitric oxide (NO) generation system includes at least one pair of electrodes configured to generate a product gas containing NO from a flow of a reactant gas; and a controller configured to regulate the amount of nitric oxide in the product gas produced by the at least one pair of electrodes by utilizing duty cycle values of plasma pulses selected from a plurality of discrete duty cycles to produce a target rate of NO production based on an average of discrete production rates associated with each of the plurality of discrete duty cycles.

A device (102) provides respiratory treatment for SDB (including mild OSA) and other respiratory conditions. A flow generator warms and humidifies gas at controlled flow levels. For example, the device (102) delivers breathable gas to the upper airway at flow rates of about 10-35 Liters/minute. Levels of flow rate, temperature and/or humidification of the device may be automatically adjusted in response to the detection of SDB events. The device may also automatically deliver adjustments of any of the levels in accordance with detected phases of respiratory cycles. In some embodiments, the device automatically delivers distinct levels to either of the nares based on independent control of flow to each nare. A warm-up procedure controls temperature and humidity at a desired target during a ramp-up of flow in the set therapy level. A cool-down procedure controls temperature above the dewpoint to avoid condensation internal to the device and patient interface.

Embodiments disclosed herein are directed to ventilation devices, systems, and methods for applying positive end expiratory pressure (PEEP) to the lungs of a patient. For example, applying above atmospheric pressure to the lungs of the patient may mitigate alveolar collapse in the lungs and/or may have other health benefits for the patient.

The device of the invention is equipped with a pressure sensor and a control unit, and the control unit judges a point at which a pressure gradient calculated from a signal of the pressure sensor becomes larger in the absolute value than a pressure gradient threshold as an inspiration sensing point and starts respiratory gas supply. In addition, the device judges from a frequency of the inspiration sensing point during predetermined time whether a pressure gradient threshold used as a criterion for the inspiration sensing point corresponds to an activity state of the user, and when the pressure gradient threshold does not correspond to the activity state, switches the pressure gradient threshold to another threshold and thus fits the pressure gradient threshold to the activity state.

A respiratory assistance system can include a humidifier used for delivery of heated and humidified gases to a patient includes a humidification chamber with an inlet and associated sensor, an associated heater and sensor, an inspiratory conduit with an associated heater and sensor, and an unheated patient interface, such as a face mask. A humidifier can include a control system configured to change a humidification chamber outlet temperature set point or an amount of generated humidity, including for example, a maximum outlet temperature set point, as a function of inlet gas temperature. The control system can reduce and/or minimize rainout (i.e. condensate) while maintaining a substantially consistent humidity in the gases delivered to a patient.

A method for determining the functional residual capacity of a patient's lung, includes supplying a first inspiratory breathing gas having a first proportion of a metabolically inert gas, supplying a second inspiratory breathing gas having a second proportion of the metabolically inert gas, determining any arising volume difference, which represents a difference in volume between a volume of inspiratory and of expiratory metabolically inert gas for a determination period, determining the functional residual capacity taking into account the volume difference and a proportion difference between a first proportion quantity and a second proportion quantity, which represent the first proportion and the second proportion of the metabolically inert gas, respectively, and determining a base difference, which represents a difference between a tidal volume of inspiratory metabolically inert gas and of expiratory metabolically inert gas.