Methods and apparatus for flow therapy

A flow therapy system comprising:

• a non-sealing patient interface, and
• a flow therapy apparatus comprising:
• a flow generator,
• one or more sensors, and
• a controller configured to:
• control the flow generator to administer gas at a gas flow rate to the patient through both nostrils using the non-sealing patient interface,
• for each nostril, measure from the one or more sensors a nostril parameter associated with that nostril, the nostril parameter being one or more of:
• a respiratory demand of that nostril,
• a parameter indicative of the respiratory demand of that nostril, or
• a parameter from which the respiratory demand of that nostril is configured to be derived,
• wherein the nostril parameter associated with each nostril is a pressure of a nasal passage for that nostril, or a pressure of a conduit leading to the nasal passage of that nostril, or both;
• calculate a respiratory demand of the patient from the nostril parameter associated with each nostril using a relationship between the nostril parameter associated with each nostril and the respiratory demand of the patient, wherein the respiratory demand of the patient is the gas flow rate required by the patient during breathing,
• wherein the respiratory demand is calculated by:
• combining the pressure of the nasal passage for each nostril, and using the relationship to determine an offset flow rate or a respiratory demand flow rate for the patient using the combined pressure of the nasal passage for each nostril, or
• using the relationship, determining an offset flow rate or a respiratory demand flow rate for each nostril using the pressure of the nasal passage for each nostril and combining the offset flow rate or nasal respiratory demand flow rate for each nostril to provide the offset flow rate or respiratory demand flow rate for the patient.

A respiratory support system comprising:

• a non-sealing patient interface, and
• a respiratory support apparatus comprising:
• a flow generator,
• one or more sensors, and
• a controller configured to:
• control the flow generator to administer gas at a gas flow rate to the patient through both nostrils using the non-sealing patient interface,
• for each nostril, measure from the one or more sensors a nostril parameter associated with that nostril, the nostril parameter being one or more of:
• a respiratory demand of that nostril,
• a parameter indicative of the respiratory demand of that nostril, or
• a parameter from which the respiratory demand of that nostril is configured to be derived,
• wherein the nostril parameter associated with each nostril is a pressure of a nasal passage for that nostril, or a pressure of a conduit leading to the nasal passage of that nostril, or both;
• calculate a respiratory demand of the patient from the nostril parameter associated with each nostril using a relationship between the nostril parameter associated with each nostril and the respiratory demand of the patient, wherein the respiratory demand of the patient is the gas flow rate required by the patient during breathing,
• wherein the respiratory demand is calculated by:
• combining the pressure of the nasal passage for each nostril, and using the relationship to determine an offset flow rate or a respiratory demand flow rate for the patient using the combined pressure of the nasal passage for each nostril, the relationship being stored in the controller, or
• using the relationship, determining an offset flow rate or a respiratory demand flow rate for each nostril using the pressure of the nasal passage for each nostril and combining the offset flow rate or nasal respiratory demand flow rate for each nostril to provide the offset flow rate or respiratory demand flow rate for the patient.