A breathing assistance apparatus for providing respiratory therapy

A breathing assistance apparatus configured to deliver respiratory therapy to a patient, the breathing assistance apparatus comprising:

• a flow generator, and a humidifier in fluid communication with the flow generator,
• a controller configured to control the breathing assistance apparatus,
• wherein the controller is configured to be in communication with at least one gases property sensor, wherein the controller is configured to calculate a determined flow rate and/or a determined pressure of the gases in a gases flow pathway based on an least an output of the at least one gases property sensor,
• wherein the controller is configured to generate one or more alarms based on the determined flow rate and/or determined pressure, wherein the one or more alarms comprise one or more of:
• an over pressure alarm,
• an elevated pressure alarm,
• a low pressure alarm,
• an excessive leak alarm,
• a blockage alarm, or
• an apnea alarm.