| 摘要 |
Portable peak expiratory flow rate (PEFR) monitoring devices are known that use whistles or reeds that are theshold-activated in order to register PEFR. This invention provides a PEFR monitoring device including a threshold-activated reed (16) located in an outlet formed in a body. The body comprises inlet and outlet body shells (12, 14) that are interengageable with one another in a plurality of rotational positions of the shells relatively to one another. A vent opening (26) extends axially along the length of the outlet shell (14). The inlet shell (12) includes a mouthpiece (18) that extends into a cylindrical occluder (20), the upper edge (20.1) of which is spirally shaped. When the shells are interengaged, the occluder (20) extends into the outlet shell to occlude the vent to a greater or lesser extend, depending on the rotational position of the shells (12, 14), thereby to direct a greater or lesser proportion of the flow through the reed assembly (16). The body shells (12, 14) that are lockable to one another to set the vent outler size, normally in accordance with a predetermined treatment protocol.
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