Nasal high flow therapy device and method

A gas delivery assembly comprising a nasal sub-system (21) to be connected to a nose of a patient for delivering a respiratory gas to the patient, and a measurement module (44), wherein the nasal sub-system (21), comprises:

• a hollow body (22) with an inner chamber (22a) and an inlet (22b) for receiving a respiratory gas, and
• a pair of nasal prongs (23, 24), in fluid communication with the inner chamber 22a of the hollow body 22, each nasal prong (23, 24) comprising a pair of inner channels (23b, 23c;
• 24b, 24c), each inner channels (23b, 23c;
• 24b, 24c) comprising a first channel (23b;
• 24b) and a second channel (23c;
• 24c) arranged in parallel, each first passage (23b;
• 24b) fluidly connecting the internal chamber (22a) of the hollow body (22) with a nostril (13, 14) of the patient (1), and each second passage (23c, 24c) fluidly connecting a nostril (13, 14) with a vent conduit (25) arranged in the hollow body (22) and in fluid communication with the atmosphere via at least one venting port (25a), and
• wherein the measurement module (44) comprises a main module body (144) in fluid communication with the nasal sub-system (21), said main module body (144) comprising:
• a first inner gas conduct in fluid communication with an outlet port (225) of the nasal sub-system (21), and
• a hollow expansion portion (44d) comprising an inner volume in fluid communication with the vent conduit (25) of the nasal sub-system (21).