prebreathe

transitive verb
pre·​breathe | \ (ˈ)prē-ˈbrēt͟h How to pronounce prebreathe (audio) \
prebreathed; prebreathing

Medical Definition of prebreathe

: to breathe (pure oxygen) to purge the blood of nitrogen content in preparation for an activity (as a space walk) that involves exposure to a significant change in pressure which might otherwise cause decompression sickness

Other Words from prebreathe

prebreathing \ -​iŋ How to pronounce prebreathing (audio) \ noun