Cerebral Oxygen Saturation as a Predictor of Impending Gravity Induced Loss of Consciousness (GLOC)

Abstract

Abstract : Aerospace medicine has been challenged by the phenomena of Gz induced Loss Of Consciousness (GLOC) since as early as World War I when pilots described fainting while pulling out of dives during aerial combat (I). Gz is the force of gravity holding us to the ground, but pilots are exposed to forces considerably in excess of the I Gz that is experienced when simply standing on the ground. As an aircraft pitches to change direction, as in a loop or steep turn, additional Gz is experienced that crushes a pilot into the cockpit seat. This is similar to the forces experienced during sharp turns in a car or rollercoaster, only significantly stronger due to the high speeds of flight. 2 Gz represents a doubling of the force of gravity, while 9 Gz effectively multiplies a pilot's body weight by nine. Current fighter aircraft are capable of reaching and sustaining 9 Gz for short periods of time. High +Gz forces cause pooling of blood in the lower extremities and deviation of internal organs downward into the seat. When too much blood is drawn away from the head by high Gz the brain can run low on oxygen resulting in the phenomena known as GLOC.