The occlusion
time automatically started after 1/3 of inspiration. At the
end of inspiration, the patient was prevented from expiration
for the period of time set as occlusion time. The patient had
to keep the mouthpiece in his mouth and hold his breath for
10 s. The pressure curve displayed during the occlusion showed
whether the patient had held his breath or whether he had tried
to expire or inspire despite the occlusion.