Exposure to Non-Steady-State Oxygen Is Reflected in Changes to Arterial Blood Gas Values, Prefrontal Cortical Activity, and Systemic Cytokine Levels.

Onboard oxygen-generating systems (OBOGSs) provide increased inspired oxygen (FO) to mitigate the risk of neurologic injury in high altitude aviators. OBOGSs can deliver highly variable oxygen concentrations oscillating around a predetermined FO set point, even when the aircraft cabin altitude is relatively stable. Steady-state exposure to 100% FO evokes neurovascular vasoconstriction, diminished cerebral perfusion, and altered electroencephalographic activity.

Clinical Impact of Cabin Altitude Restriction Following Aeromedical Evacuation.

Combat medical care relies on aeromedical evacuation (AE). Vital to AE is the validating flight surgeon (VFS) who warrants a patient is "fit to fly." To do this, the VFS considers clinical characteristics and inflight physiological stressors, often prescribing specific interventions such as a cabin altitude restriction (CAR).