
1) Breathing gas
Found on
https://www.crosswordclues.com/clue/heliox

Heliox is a breathing gas composed of a mixture of helium (He) and oxygen (O2). Heliox is a medical treatment for patients with difficulty breathing. The mixture generates less resistance than atmospheric air when passing through the airways of the lungs, and thus requires less effort by a patient to breathe in and out of the lungs. Heliox has bee...
Found on
http://en.wikipedia.org/wiki/Heliox
[cryogenic equipment] Heliox is a cryogenically cooled system produced by Oxford Instruments. Presently available in 2 varieties, the VL and TL, vertically loaded and top-loaded respectively. They are both pumped 3He cryostats, the TL capable of magnetic fields of up to 14 T, and the VL capable of achieving magnetic fields of up to 2 T. The...
Found on
http://en.wikipedia.org/wiki/Heliox_(cryogenic_equipment)

Type: Term Pronunciation: hē′lē-oks Definitions: 1. A mixture of helium (60-70%) and oxygen (30-40%) to treat acute asthma attacks.
Found on
http://www.medilexicon.com/medicaldictionary.php?t=39652

mixture of helium and oxygen, usually used as a breathing gas during very deep dives.
Found on
https://dipndive.com/blogs/stories/diving-lingo-101-glossary-of-terms-phras

A breathing mixture of gases consisting entirely of Helium and Oxygen. This is used to eliminate Nitrogen narcosis and to control the affects of Oxygen toxicity, by eliminating the Nitrogen and reducing the Oxygen in the breathing mix. Another benenfit is reduced effort of breathing due to the lower density of helium. There are a few disadvantages,...
Found on
https://www.scubadoctor.com.au/scuba-diving-glossary.htm
No exact match found.