Method of delivering medical gases via a nasal cannula assembly with flow control passage communicating with a deformable reservoir

A method for treating pulmonary vasoconstriction in a patient, comprising:

• a) providing a nasal cannula assembly (10) adapted to deliver gases to a patient, the nasal cannula assembly (10) comprising:
• A) a hollow body (4) configured to be capable of acting as a gas conduct or a gas manifold and comprising an internal chamber (7) defining a first compartment (1),
• B) the first compartment (1) and a second compartment (2) separated by a separation wall (6),
• C) a pair of nasal prongs (5) in fluid communication with the first compartment (1),
• D) the first compartment (1) comprising a first inlet (11) forming a side gases entry in fluid communication with a gas transport conduct and configured to conduct a first gas into said first compartment (1),
• E) the second compartment (2) having a fully inflated internal volume for a gas of about 0.5 to 5 ml, the second compartment (2) comprising,
• a second inlet (12) configured to conduct a second gas into said second compartment (2), and
• a deformable wall (14) forming a part of a boundary between the second compartment (2) and a room atmosphere such that the compliance of the second compartment (2) is not less than 5 ml/cm H2O while filling but is less than 0.1 ml/cm H2O once the second compartment (2) is full,
• F) the separation wall (6) comprising two flow restriction channels (35)
• having a rounded edge at an entrance from second compartment (2) and
• having a reentrant aperture at an exit into the first compartment (1) and
• which are oriented and arranged in the separation wall (6) directly opposite the pair of nasal prongs (5) to thereby be capable of
• a. permitting a passage of gas from the second compartment (2) to the first compartment (1) in a reduced pressure state during an inhalation phase and
• b. preventing a majority of flow of the second gas from the second compartment (2) to the first compartment (1) in a higher pressure state, during an exhalation phase, relative to the passage of gas during the reduced pressure state, during an inhalation phase, such that during the higher pressure state exhalation phase the majority of flow of the second gas entering the second compartment (2) from the second inlet (12) is retained in the second compartment (2) causing the deformable wall (14) to deform and increase the volume of the second compartment (2) by at least 50% volume, as compared to the second compartment (2) volume at the end of the previous reduced pressure state inhalation phase,
• b) providing a therapeutically-effective amount of a NO-containing gas to said patient through said nasal cannula assembly (10) for inhalation to thereby reduce the pulmonary vasoconstriction in the patient.