Properties 

Helium has a lower density than air, nitrogen and oxygen. The low density of gas results in a lowering of the Reynolds’ number and thus a return from turbulent to laminar flow in some situations . By increasing laminar flow, the efficiency of breathing is increased. This physical characteristic is used to treat patients with upper airway obstruction to reduce the work of breathing and improve oxygenation. As a result of its lower density, patients receiving helium have a typical squeaky voice because higher frequency vocal sounds are transmi?ed. Helium is used in the measurement of lung volumes because of its very low solubility.

Uses 

1. In medical devices, such as an intra-aortic balloon pump.

2. Improves flow dynamics in patients with airway obstruction. 

3. Measurement of FRC (helium dilution technique). 

Presentation and storage 

Helium is a light inert gas, present in air and natural gas. It is the second most abundant element after hydrogen. It is presented as either Heliox (79% helium and 21% oxygen) in white cylinders with white and brown quartered shoulders or as 100% helium in brown cylinders at 137 bar.