Nasal high flow therapy assembly comprising: A) a nasal gas-delivery system to be connected to a nose of a patient for delivering a respiratory gas to the patient, comprising: - a hollow body with an inner chamber comprising an inlet for receiving a respiratory gas, and - a pair of nasal prongs (23, 24) in fluid communication with the inner chamber of the hollow body, each nasal prong (23, 24) comprising a first inner passage (123; 124) fluidly connecting the internal chamber of the hollow body with a nostril (13, 14) of the patient, and - the hollow body comprises a pair of second passages (125; 126) for fluidly connecting a nostril (13, 14) with a vent conduit arranged in the hollow body, said vent conduit comprising one venting port, charecterized in that the nasal high flow therapy assembly further comprises: B) a sensing module comprising a hollow body comprising an internal chamber with an inlet orifice, an outlet orifice, a first port and, a second port and an inner wall arranged between the first and second ports (44a, 44b) and radially projecting into the internal chamber thereby forming a restriction of passage for the gas in said internal chamber, said first and second ports (44a, 44b) each comprising an exit orifice (244a, 244b), the inlet orifice of the sensing module being fluidly connected to the venting port of the vent conduit of the nasal gas-delivery system. A) a nasal gas-delivery system to be connected to a nose of a patient for delivering a respiratory gas to the patient, comprising: - a hollow body with an inner chamber comprising an inlet for receiving a respiratory gas, and - a pair of nasal prongs (23, 24) in fluid communication with the inner chamber of the hollow body, each nasal prong (23, 24) comprising a first inner passage (123; 124) fluidly connecting the internal chamber of the hollow body with a nostril (13, 14) of the patient, and - the hollow body comprises a pair of second passages (125; 126) for fluidly connecting a nostril (13, 14) with a vent conduit arranged in the hollow body, said vent conduit comprising one venting port, charecterized in that the nasal high flow therapy assembly further comprises: - a hollow body with an inner chamber comprising an inlet for receiving a respiratory gas, and - a pair of nasal prongs (23, 24) in fluid communication with the inner chamber of the hollow body, each nasal prong (23, 24) comprising a first inner passage (123; 124) fluidly connecting the internal chamber of the hollow body with a nostril (13, 14) of the patient, and - the hollow body comprises a pair of second passages (125; 126) for fluidly connecting a nostril (13, 14) with a vent conduit arranged in the hollow body, said vent conduit comprising one venting port, B) a sensing module comprising a hollow body comprising an internal chamber with an inlet orifice, an outlet orifice, a first port and, a second port and an inner wall arranged between the first and second ports (44a, 44b) and radially projecting into the internal chamber thereby forming a restriction of passage for the gas in said internal chamber, said first and second ports (44a, 44b) each comprising an exit orifice (244a, 244b), the inlet orifice of the sensing module being fluidly connected to the venting port of the vent conduit of the nasal gas-delivery system.