Current and Emerging Technology in G-LOC (G-Induced Loss of Consciousness) Detection: Noninvasive Monitoring of Cerebral Microcirculation Using Near Infrared
Abstract
G-induced loss of consciousness (G-LOC) has emerged as an important operational problem of high-performance aircraft. Since it appears that G-LOC will continue to be a problem, a requirement exists to detect its occurrence in pilots so that the aircraft may be placed on autopilot. One excellent method of detecting G-LOC physiologically, one would assume, would be based on the oxidative status of the brain. This determination can be made noninvasively with an Oxidative Metabolism Near-Infrared monitor using 4 wave lengths (OMNI-4). The OMNI-4 is capable of measuring the relative quantities in the brain of hemoglobin (Hb), oxygenated hemoglobin (HbO2), blood volume (BV), and oxidative status of cytochrome c oxidase. This instrument was tested on subjects in the USAFSAM human-use centrifuge at +3, 4, and 5 Gz with onset rates of 1 G/s. Results showed changes within the brain, as expected, during increased G with reductions in Hb, BV, and HbO2. Cytochrome c oxidase measurements were inconclusive. Immediately following G exposure, Hb, BV, and HbO2 'overshoots' occurred suggesting vasodilation of the cerebral microcirculation. The use of OMNI-4 in the laboratory and is possible role as a detector of G-LOC in pilots are discussed including suggestions for future developments.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 01, 1988
- Accession Number
- ADA191149
Entities
People
- D. H. Glaister
Organizations
- United States Air Force School of Aerospace Medicine