Control for pressure of a patient interface

• Main Authors: Holley, Liam, Austin, Benjamin Matthew
• Format: Patent
• Language: English
• Published: 25.06.2021
• Subjects: DEVICES FOR INTRODUCING MEDIA INTO, OR ONTO, THE BODY; DEVICES FOR PRODUCING OR ENDING SLEEP OR STUPOR; DEVICES FOR TRANSDUCING BODY MEDIA OR FOR TAKING MEDIA FROMTHE BODY; HUMAN NECESSITIES; HYGIENE; MEDICAL OR VETERINARY SCIENCE

A method and/or apparatus to supply breathable gas at positive pressure to a patient through a patient interface. It can be undesirable for exhaled gas from a patient to be continuously vented to the ambient atmosphere and a vent valve may be used with a respiratory device, where the vent valve may selectively block fluid communication between components, such as the flow generator, the patient interface, and/or the vent. In such circumstances known methods of determining the gas pressure in the patient interface may not be accurate. In one form of the technology a controller uses one process for determining gas pressure in the interface when a conduit to a pressure sensor is blocked, and a second process when the conduit to the sensor is unblocked. An expiratory flow model may be used to determine an expiratory characteristic such as an expiratory flow rate or pressure in the patient interface where an indicative measure may not be available. The expiratory flow model may receive inputs based on a measure of the patient's respiration, such as the tidal volume, peak inspiratory flow rate or length of inspiration. The expiratory characteristic may be used by a controller to control a pressure in the patient interface to provide respiratory therapy to a patient at or close to a target pressure.