Hypoxia
Hypoxia was a medical condition when a person suffered from a lack of oxygen, which generally left them disoriented and gasping for air. 

The administration of tri-ox compound helped a patient strengthen their cardiopulmonary system, and allowed them to better withstand the effects hypoxia. James T. Kirk suffered from hypoxia during the koon-ut-kal-if-fee battle he fought with Spock in 2267. (; )

When the  received a distress call from the  in 2365, and discovered that the ship had an outer-hull breach, it was feared that there may be an internal explosion, which would make the passengers aboard prone to severe hypoxia. ()

In 2373, Tuvok believed Doctor Vatm had become delirious from lack of oxygen. ()

In 2374, Miles O'Brien and Julian Bashir suffered from hypoxia when oxygen began to run out when they were in a miniaturized state inside of an isolinear access panel. ()

Later that year, Bashir warned Lisa Cusak that she would experience the effects of hypoxia once she ran out of tri-ox compound. ()

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de:Hypoxie
Medical conditions