Vyaire MicroLab Manuel D'utilisation page 68

'Touch' the MVV icon to select this mode of testing and the display
will instruct the patient to start breathing hard to commence the
test.
It is recommended that the patient perform 3 tidal breathing
maneuvers prior to performing hard and fast rapid breathing
(required for the MVV maneuver).
The patient should be instructed to tidally
breathe. The tidal breaths are automatically
detected prior to commencing the MVV
maneuver.
68