Nasal cannula assembly with flow control passage communicating with a deformable reservoir
The invention concerns a nasal cannula assembly ( 10 ) adapted to deliver gases to a patient comprising a first compartment ( 1 ) and a second compartment ( 2 ) separated by a separation wall ( 6 ); a pair of nasal prongs ( 5 ) in fluid communication with the first compartment ( 1 ); the first compartment ( 1 ) comprising a first inlet ( 11 ) for introducing a first gas into said first compartment ( 1 ); the second compartment ( 2 ) comprising a second inlet ( 2 ) for introducing a second gas into said second compartment ( 2 ); and the separation wall ( 6 ) comprising at least one flow restriction element ( 35 ) for controlling the passage of gas from the second compartment ( 2 ) to the first compartment ( 1 ).
1. 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 H 2 O while filling but is less than 0.1 ml/cm H 2 O once the second compartment ( 2 ) is full,
f) the separation wall ( 6 ) comprising two flow restriction channels ( 35 )
A) having a rounded edge at an entrance from the second compartment ( 2 ) and
B) having a reentrant aperture at an exit into the first compartment ( 1 ) and
C) which are oriented and arranged in the separation wall ( 6 ) directly opposite the pair of nasal prongs ( 5 ) to thereby be capable of
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
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 internal 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.
2. The nasal cannula assembly according to claim 1 , further comprising one or more orifices ( 13 ) in the first compartment ( 1 ) defining a fluid communication from an internal chamber ( 7 ) to an external atmosphere.