A method, system and apparatus for assessing the coupling between lung perfusion and ventilation in a patient who is mechanically ventilated or who is breathing spontaneously through a conventional artificial airway is provided. Embodiments of the apparatus comprise an adaptor configured to fit between the artificial airway and mechanical ventilator, a measuring chamber in constant fluid communication with the adaptor via one or more measuring chamber sampling ports, and a monitoring unit where data obtained from temperature and relative humidity sensors located in the measuring is calibrated, sampled, logged and analyzed together with anthropometric patient data to display a coupling index Qi and to enable ongoing diagnostic cardio-pulmonary monitoring of a patient by comparing changes in the patient's index during a monitoring interval.

A respiratory assistance apparatus has a gases inlet configured to receive a supply of gases, a blower unit configured to generate a pressurised gases stream from the supply of gases; a humidification unit configured to heat and humidify the pressurised gases stream; and a gases outlet for the heated and humidified gases stream. A flow path for the gases stream extends through the respiratory device from the gases inlet through the blower unit and humidification unit to the gases outlet. A sensor assembly is provided in the flow path before the humidification unit. The sensor assembly has an ultrasound gas composition sensor system for sensing one or more gas concentrations within the gases stream.

A nasal cannula arrangement for use as part of systems for delivery respiratory gases to a patient is disclosed. The nasal cannula arrangement includes a manifold part adapted to receive gases from a delivery conduit. The manifold includes one but preferably a pair of prongs extending upward and curving towards the rear of the manifold. The prongs are inserted into the nostrils of the patient and deliver gases to a patient. The prongs have a cut out on the rear side of the prongs. The cut out forms a gases outlet in the prongs and are shaped such that the area of the cut out area is greater than the cross sectional area of the prongs at the entry point to the prongs.

A respiratory treatment apparatus provides respiratory treatment with improved power management control to permit more efficient power consumption and power supply units, such as battery powered operation. In one embodiment, power management prioritizes the flow generator (104) over other accessories such as the heating elements (111, 135) of a humidifier (112) and/or a delivery tube. The flow generator may control operations of the heating elements as a function of a detected respiratory cycle. For example, the timing of operation of the heating elements may be interleaved with the portion of an inspiratory phase of the respiratory cycle to permit the flow generator to operate during a peak power operation without a power drain or with a lower power drain from these components. Operations of distinct sets of components of the system (e.g., different heating elements) may also be interleaved to prevent simultaneous peak power operations.

The present invention provides for an improved method of determining a water out condition in a humidified gases supply apparatus. The method includes a two step process including a primary determination of a water out condition and a secondary determination of a water out condition. This primary determination is made during observation of the normal operation of the apparatus. During the secondary determination the method takes temporary control over the humidifying part of the apparatus. The secondary determination confirms or contradicts the primary determination.

Systems and methods for non-invasive ventilation are provided. The systems may include a gas source that provides breathing gases to a patient through one or more of a primary flow path (PFP) and a flushing flow path (FFP). The system may include a control assembly configured to open and restrict gas flow through the PFP. When the PFP is open, a significant portion of the gas flows through the PFP while the remaining gas flows through the FFP. When the PFP is restricted, a significant portion of the gas flows through the FFP. Increased flow through the FFP may have a high velocity (especially relative to the flow through the PFP). Gas delivered through the FFP may be used to flush dead space. One or both flow paths may contribute to inspiratory positive airway pressure (IPAP), expiratory positive airway pressure (EPAP), and/or positive end expiratory pressure (PEEP).

A pressure regulating or pressure relief device comprises an inlet and an outlet chamber with an outlet. The inlet is in fluid communication with the outlet chamber. A valve seat is located between the inlet and the outlet. A valve member is biased to seal against the valve seat, and displaces from the valve seat by an inlet pressure at the inlet increasing above a pressure threshold to allow a flow of gases from the inlet to the outlet via the outlet chamber. The flow of gases through the outlet causes an outlet pressure in the outlet chamber to act on the valve member together with the inlet pressure to displace the valve member from the valve seat.

Systems and method for conducting respiratory therapy in a respiratory system can adjust a flow of respiratory gases to a patient based upon a detected patient breath cycle. The respiratory system can include a non-sealed patient interface. The respiratory system can be configured to deliver a high flow therapy. A patient breath cycle may be determined using one or more measured parameters, such as a flow rate, a blower motor speed, and/or a system pressure. A flow source may be adjusted to have a phase matching that of the patient's breath cycle, such that flow in increased in response to the patient inhaling, and decreased in response to the patient exhaling.

A vent assembly for a respiratory pressure therapy (RPT) system. The vent assembly may include a vent housing having a first orifice configured to receive the flow of pressurized gas from the RPT device and the vent housing having a plurality of holes to discharge pressurized gas to atmosphere; a vent housing connector having a second orifice configured to direct the flow of pressurized gas to the patient interface; and a heat and moisture exchanger (HME) comprising an HME housing and an HME material within the HME housing, wherein the vent housing and the vent housing connector are configured to be connected to, at least in part, form a cavity, and wherein the HME is positioned in the cavity when the vent assembly is assembled.

An apparatus for humidifying a flow of pressurised, breathable air includes varying a first pressure of the flow of breathable gas to vary a level of thermal engagement between the conductive portion of the reservoir and the heater plate, varying a height of the variable portion varies a level of thermal engagement between the conductive portion of the reservoir and the heater plate, use of a humidifier reservoir base component with a maximum water capacity substantially equal to the predetermined maximum volume of water of the humidifier reservoir or the use of intersecting inlet and outlet axes.