Heat and moisture exchanger for patient interface
A patient interface may include: a plenum chamber pressurisable to a therapeutic pressure; a seal-forming structure connected to the plenum chamber, the plenum chamber being constructed and arranged to seal with a region of the patients face; a positioning and stabilising structure configured to provide a force to hold the seal-forming structure in a therapeutically effective position on the patients head; a vent structure configured to allow a continuous flow of gases exhaled by the patient from an interior of the plenum chamber to ambient; and a material configured to adsorb water vapour from gases exhaled by the patient and desorb water vapour into the flow of air at the therapeutic pressure, the material being positioned within the plenum chamber.
1 . A patient interface comprising:
a plenum chamber pressurisable to a therapeutic pressure of at least 4 cmH2O above ambient air pressure by a flow of air at the therapeutic pressure for breathing by a patient, the plenum chamber comprising a main frame and a removable frame that is removably connectable to the main frame, the main frame comprising two plenum chamber connectors, and each of the plenum chamber connectors being positioned on a corresponding lateral side of the main frame and configured to receive the flow of air at the therapeutic pressure;
a seal-forming structure connected to the plenum chamber, the seal-forming structure being constructed and arranged to seal with a region of the patient's face at least partly surrounding an entrance to the patient's airways, the seal-forming structure having a sealing flange and a hole in the sealing flange to deliver the flow of air at the therapeutic pressure to at least the patient's nares, and the seal-forming structure being constructed and arranged to maintain the therapeutic pressure in the plenum chamber throughout the patient's respiratory cycle in use;
a positioning and stabilising structure comprising two conduits configured to hold the seal-forming structure in a therapeutically effective position on the patient's head, each of the conduits being configured to be positioned on a corresponding lateral side of the patient's head in use, and each of the conduits being configured to connect to a corresponding one of the two plenum chamber connectors;
a vent structure comprising vent holes configured to allow a continuous flow of gas from an interior of the plenum chamber to ambient while the plenum chamber is pressurized by the flow of air at the therapeutic pressure and during inhalation, exhalation, and breath pause, and the vent holes being sized and shaped to maintain the therapeutic pressure in the plenum chamber in use;
a material configured to adsorb water vapour from gases exhaled by the patient and desorb water vapour into the flow of air at the therapeutic pressure, the material being attached to the removable frame such that the removable frame and the material are removable from the main frame together, and the material being shaped and dimensioned to be positioned within the plenum chamber, when the removable frame is removably connected to the main frame, such that at least a portion of the flow of air at the therapeutic pressure entering the plenum chamber from the two plenum chamber connectors passes through the material before entering the patient's airways,
wherein the vent holes are positioned such that, in use, a portion of the flow of air at the therapeutic pressure travels to ambient through the vent holes without passing through the material.
2 . The patient interface of claim 1 , wherein the material further comprises a salt on a surface of the material.
3 . The patient interface of claim 1 , wherein the removable frame further comprises the vent holes.
4 . The patient interface of claim 3 , wherein the material is shaped and dimensioned to be positioned within the plenum chamber, when the removable frame is removably connected to the main frame, so that gas exhaled by the patient must pass through the material before exiting to ambient through the vent holes.
5 . The patient interface of claim 3 , wherein the vent holes include two groups of vent holes, each of the groups of vent holes being positioned proximal to a corresponding lateral side of the removable frame.
6 . The patient interface of claim 3 , further comprising two supports extending from the removable frame, the material being attached to the supports such that the material is spaced from the removable frame and a void is at least partly formed by the removable frame, the material, and the supports.
7 . The patient interface of claim 6 , wherein the two plenum chamber connectors are pneumatically connected to the void to direct the flow of air at the therapeutic pressure to the void.
8 . The patient interface of claim 7 , wherein the vent holes are pneumatically connected to the void to allow air in the void to pass through the vent holes to ambient.
9 . The patient interface of claim 1 , wherein the material further comprises a posterior surface that faces the patient's face in use, the posterior surface being positively curved to avoid contact with the patient's face during use.
10 . The patient interface of claim 1 , wherein the seal-forming structure is configured to leave the patient's mouth uncovered and the seal-forming structure further comprises nasal pillows or a nasal cradle.
11 . The patient interface of claim 1 , wherein the seal-forming structure is configured to seal around the patient's nose and mouth.
12 . The patient interface of claim 1 , wherein the material is positioned within the plenum chamber so that any portion of the flow of air at the therapeutic pressure that enters the patient's airways must pass through the material before entering the patient's airways.
13 . A respiratory pressure therapy (RPT) system comprising:
the patient interface of claim 1 ;
a respiratory pressure therapy (RPT) device configured to generate the flow of air at the therapeutic pressure;
an air circuit configured to connect the RPT device and the patient interface to direct the flow of air at the therapeutic pressure from the RPT device to the patient interface, and
wherein the RPT system does not include a humidifier.
14 . The patient interface of claim 1 , wherein the material comprises foam.
15 . The patient interface of claim 1 , wherein the material comprises paper.
16 . The patient interface of claim 1 , wherein the removable frame is removably connectable to the main frame with a friction fit or a snap fit.
17 . The patient interface of claim 1 , wherein the removable frame further comprises a lip seal configured to seal between the removable frame and the main frame when the removable frame is removably connected to the main frame.
18 . The patient interface of claim 1 , wherein the removable frame further comprises an outer grip surface configured to allow the patient to grasp to remove the removable frame from the main frame or connect the removable frame to the main frame.
19 . The patient interface of claim 1 , wherein the patient interface is configured to leave the patient's mouth uncovered.
20 . The patient interface of claim 1 , wherein the seal-forming structure is configured to seal around the patient's nose and mouth, and the patient interface is configured to allow the patient to breath from ambient in the absence of a flow of pressurised air.
21 . The patient interface of claim 5 , wherein a portion of each of the groups of vent holes is positioned laterally outward of a lateralmost edge of the material.