Currently it is common medical wisdom that HELIOX (mixture of Helium in Oxygen) with a
fraction of Helium below 60% is not effective in reducing airway obstruction. The
investigators test the hypothesis that HELIOX with a fraction of Helium below 60% is still
effective in relieving airway obstruction in a double-blind, randomized and controlled
clinical PoC study with experimental upper airway obstruction.