strausd at fuse.net wrote:
>Today in a local paper, they had a picture of a lady inhaling helium in
>a celebration. I know of the short-term effects on the vocal chords but
>what about risks from this gas.
Helium is an inert gas that is used in medicine in cases of obstructive
lung disease (reduces pulmonary work, may improve O2 and CO2 exchange) and
for diagnostic purposes (spirometry). It is also used in gas mixtures by
deep water divers to prevent "the bends" and inert gas narcosis.
Thus, as long as there is sufficient O2 present it is probably safe to
breathe helium (e.g., you can't breathe 100% helium for very long). The
only adverse effect of helium mixtures is due to condensation of water
droplets that irriate the upper airway, causing coughing. See the text
Goodman and Gilman's "The Pharmacological Basis of Therapeutics".