Nasal mask for carbon dioxide gas measurement
A nasal mask is adapted to attached on a face of a subject so as to cover a nose of the subject. A shell has a contact edge adapted to be brought into close contact with the face of the subject, thereby forming a sealed space therein. An attachment portion is disposed in the shell and has an inner space. The attachment portion is configured to detachably engage with a sensor disposed outside the shell and operable to measure concentration of carbon dioxide gas expired from the nostrils. A guide member is disposed inside the shell and forming a passage adapted to introduce expired gas from the nostrils into the inner space. The shell is formed with an inlet adapted to introduce external gas into the sealed space. The expired gas is guarded by the guide member from the external gas introduced through the inlet. The attachment portion is formed with an outlet adapted to discharge the expired gas from the inner space to the sealed space.
1. A nasal mask, adapted to be attached to a face of a subject so as to cover a nose of the subject, comprising:
a shell, having a contact edge adapted to be brought into close contact with the face of the subject, thereby forming a sealed space therein;
an attachment portion, disposed in the shell and having an inner space, the attachment portion being configured to detachably engage with a sensor disposed outside the shell and operable to measure concentration of carbon dioxide gas expired from the nostrils; and
a guide member, disposed inside the shell and forming a passage adapted to introduce expired gas from nostrils into the inner space,
a cup member integrally provided with the attachment portion and adapted to cover the nose and to block the external gas introduced through the inlet wherein:
the shell is formed with an inlet adapted to introduce external gas into the sealed space;
the expired gas is guarded by the guide member from the external gas introduced through the inlet; and
the attachment portion is formed with an outlet adapted to discharge the expired gas from the inner space to the sealed space.
2. The nasal mask as set forth in claim 1 , wherein:
the guide member is a nasal tube member adapted to be placed within the nostrils so as to communicate the nostrils and the inner space.
3. The nasal mask as set forth in claim 1 , wherein:
the guide member is a cup member integrally provided with the attachment portion and adapted to cover the nose; and
an inner space of the cup member is communicated with the inner space of the attachment portion.
4. The nasal mask as set forth in claim 1 , wherein:
the shell is formed with a recessed part adapted to receive the sensor, and the attachment portion is projected into the recessed part.
5. The nasal mask as set forth in claim 4 , wherein:
the attachment portion is monolithically formed with the shell.
6. The nasal mask as set forth in claim 4 , wherein:
the attachment portion is detachably fitted with an aperture formed in the recessed part.
7. The nasal mask as set forth in claim 1 , wherein:
the nasal mask is configured such that the expired gas travels first from the nostrils and then through the inner space and then to the sealed space.