An air delivery system includes an air flow generator to provide a pressurized flow of air, a patient interface to provide a seal with the patient's face in use, an air delivery conduit to interconnect the air flow generator and the patient interface, and a controllable vent valve to control venting from the patient interface. The vent valve is controlled to maintain a substantially constant air flow in the air delivery conduit and the air flow generator.

A respiratory assistance apparatus includes a conduit connecting a flow generator and an outlet. The conduit includes a venture formation. The apparatus further includes an oxygen inlet in fluid communication or selective fluid communication with an oxygen outlet. The oxygen outlet is directed into the conduit and toward a mouth of the venture formation. The flow generator provides a flow path for air to enter the conduit when the flow generator is not operating.

A respiratory assistance device (1) for a patient, includes a tubular element forming a main channel (5) (207) which is to be connected via the distal end (7) thereof to an airway of the patient, the main channel connecting to the exterior of the respiratory system of the patient via the proximal end (6) thereof, the device further including at least one auxiliary channel (8) (209) allowing the injection of jets of breathable gas for ventilation of the patient via the distal outlet openings (17) of the auxiliary channel(s), the outlet openings opening out into the main channel in the vicinity of the distal end thereof, deflection elements (14b) (14a) allowing the deflection of gas jets to the interior of the main channel, and an internal jet separator, coaxial and central to the main channel, which further ensures diversion of the flow for expired gases.

Provided is the OFF-VENT breathing system. The system uses novel combinations of the venturi effect, PEEP adapters, HMEs, and the adaptation of a novel oxygen delivery system for the creation of high flow therapy to maintain open airways while maintaining access to the patient's airways for medical instruments, other accessories, or to assist breathing in general. The system is designed to create high flow oxygen therapy in a manner that does not require the use of ventilators, active heating humidifiers and other expensive equipment. Embodiments described include a novel integration of the venturi system into a nasal cannula apparatus, and the novel combination of the venturi effect and a PEEP adapter into breathing systems that might include hyperinflation and Mapleson circuits.

A respiratory assistance apparatus includes a conduit connecting a flow generator and an outlet. The conduit includes a venture formation. The apparatus further includes an oxygen inlet in fluid communication or selective fluid communication with an oxygen outlet. The oxygen outlet is directed into the conduit and toward a mouth of the venture formation. The flow generator provides a flow path for air to enter the conduit when the flow generator is not operating.

A breathing assistance system for delivering a stream of heated, humidified gases to a user, comprising a humidifier unit which holds and heats a volume of water, and which in use receives a flow of gases from a gases source via an inlet port, the flow of gases passing through the humidifier and exiting via an exit port, the system further having a temperature sensor which measures the temperature of the gases exiting the humidifier unit, an ambient temperature sensor which measures the temperature of gases before they enter the humidifier unit, and a flow sensor which measures the flow rate of the gases stream, the system also having a controller which receives data from the temperature and flow sensors, and which determines a control output in response, the control output adjusting the power to the humidifier unit to achieve a desired output at the humidifier unit exit port.

Ventilation masks that have breathing regions and inner and outer wearer-engaging seals and interseal regions between the inner and outer seals that are purged with either a vacuum or a positive pressure so as to prevent contaminated breathing gases from leaking into the environments surrounding the masks. In vacuum-purged embodiments, the pressure in the interseal region is lower than the pressures in both the breathing region and the surrounding environment. In some vacuum-purged embodiments, the vacuum is created using a vacuum ejector integrated into the mask. In pressure-purged embodiments, the pressure in the interseal region is greater than the pressures in both the breathing region and the surrounding environment. In some pressure-purged embodiments, the positive pressure is provided directly from a gas source, with a mask-integrated pressure reducer located between the gas source and the breathing region to reduce the pressure in the breathing region. Corresponding methods are also disclosed.

A system for ventilating a user includes a port for supplying a mixture of gases to the user for inspiration and for receiving a mixture of gases from the user after expiration a first tube having an inlet for receiving at least one gas to ventilate the user and an outlet in fluid communication with said port for supplying said at least one gas to the port for inspiration by the user, a second tube having a first end proximate to and in fluid communication with said port and a second end distal to said port, a venturi jet proximate to and in fluid communication with the second end of the second tube, wherein at least one gas can be supplied through said venturi jet to said port via the second tube, wherein the venturi jet includes a jet having an outlet and a venturi tube, the jet being in fluid communication with a venturi tube and the venturi tube being disposed between the jet and the second end of the second tube, whereby in use the user inspires said at least one gas to ventilate the user and gas expired by the user flows from the port through the second tube and the venturi tube to exit the system.

A patient ventilation interface has a throat body defining a venturi throat that is open to ambient air, a nasal pillow disposed around the venturi throat to define a plenum between the venturi throat and the nasal pillow, a jet nozzle arranged to output ventilation gas into the venturi throat, and a pressure sensing tube having a pressure sensing port positioned to be in fluid communication with the plenum. The nasal pillow may be an integral part of the throat body. An expected error in the sensed patient airway pressure P.sub.sense may be corrected by applying a correction factor P.sub.delta indexed by the sensed patient airway pressure P.sub.sense and a jet nozzle flow V.sub.n of the jet nozzle. Delivery of the ventilation gas output by the jet nozzle may be controlled in response to the corrected patient airway pressure.