ISO 18082:2014 specifies the dimensions, the allocation and marking of non-interchangeable screw-threaded (NIST) connectors intended to be used at operating pressures up to 1 400 kPa, and for vacuum systems at pressures not greater than 60 kPa absolute.
ISO 18082:2014 specifies NIST connectors intended for use with the following medical gases:

oxygen
nitrous oxide
medical air
helium
carbon dioxide
xenon
specified mixtures of the gases listed above
oxygen-enriched air
air for driving surgical tools
nitrogen for driving surgical tools
use with vacuum.