preoxygenation
noun
pre·ox·y·gen·ation
| \ -ˌäk-si-jə-ˈnā-shən, -äk-ˌsij-ə-
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Medical Definition of preoxygenation
: inhalation of large quantities of essentially pure oxygen usually as a prelude to some activity or medical procedure in which it is desirable to minimize nitrogen and maximize oxygen in the blood and tissues