(1) A forced inspiration against a closed upper airway.
(2) The attempt to breathe in while the mouth is closed and the nostrils are pinched or plugged shut, resulting in a negative pressure in the upper airway.
The maneuver is done in patients with sleep apnea to examine the airway collapse through a flexible scope. The more marked the airway collapse is, the more severe the obstructive sleep apnea.
Compare: Valsalva maneuver