High velocity respiratory therapy unit with non-contact sensing and control

A system for providing high velocity respiratory therapy to the nare of a patient, the system comprising:

• a breathing gas source configured to output a flow of breathing gas at a flowrate of 8-60 L/min and an output pressure;
• a gas passage in fluid communication with the breathing gas source and configured to convey the flow of breathing gas from the breathing gas source;
• and
• a nasal cannula in fluid communication with the gas passage and having at least one nasal prong with an exit orifice that has a prong cross-sectional area, the nasal cannula defining a first flow path length and being configured to receive the flow of breathing gas from the gas passage and transmit the flow of breathing gas through the exit orifice;
• wherein the gas passage defines a second flow path length between the breathing gas source and the nasal cannula, the gas passage having a minimum passage cross-sectional area at a point along the second flow path length such that a ratio of the minimum passage cross-sectional area to the prong cross-sectional area is 2.5 to 5,
• wherein when breathing gas flows through the nasal cannula a pressure drop occurs in an amount corresponding to less than 35% of the output pressure, and
• wherein the at least one nasal prong exit orifice is configured so that breathing gas exiting from the exit orifice has an exit velocity of at least 40 m/s.

A method for providing high velocity respiratory therapy to the nare of a patient, the method comprising the steps of:

• outputting a flow of breathing gas from a breathing gas source at a flowrate of 8-60 L/min and a first output pressure;
• conveying the flow of breathing gas from the breathing gas source along a gas passage to a nasal cannula,
• wherein the gas passage defines a first flow path length between the breathing gas source and the nasal cannula,
• wherein the nasal cannula has at least one nasal prong with an exit orifice that has a prong cross-sectional area, the nasal cannula defining a second flow path length, and
• wherein the gas passage has a minimum passage cross-sectional area along the first flow path length such that the ratio of the minimum passage cross-sectional area to the prong cross-sectional area is 2.5 to 5, and
• wherein when breathing gas flows through the nasal cannula a pressure drop occurs in an amount corresponding to less than 35% of the first output pressure;
• and
• delivering the flow of breathing gas to the nare of a patient through the exit orifice at an exit velocity of at least 40 m/s.

A method comprising the steps of:

• outputting a flow of breathing gas from a breathing gas source at a flowrate of 8-60 L/min and a first output pressure;
• conveying the flow of breathing gas from the breathing gas source along a gas passage to a nasal cannula,
• wherein when breathing gas flows through the nasal cannula a pressure drop occurs in an amount corresponding to less than 35% of the first output pressure;
• and
• delivering the flow of breathing gas to the nare of a patient through an exit orifice of at least one nasal prong at an exit velocity of at least 40 m/s.