Q: Heliox (Helium plus oxygen) works by all of the following mechanisms except?

A) Advantage of low density 
B) Ability to increase the proportion of turbulent air flow relative to laminar airflow
C) Reduction in airway resistance, 
D) Reduction in pleural pressures swings
E) Reduction in work of breathing


Answer:  B

Heliox actually works by decreasing the proportion of turbulent air flow relative to laminar airflow. It is an objective which gets achieve by inertness and low density of helium gas. Due to laminar flow it reduces the airway resistance, pleural pressures swings and consequently work of breathing.