Dissertation
Rheoencephalography in simulated aviation environment stress
Doctor of Philosophy (Ph.D.), Drexel University
1989
DOI:
https://doi.org/10.17918/00004775
Abstract
The use of electrical impedance plethysmography of the head, or Rheoencephalography (REG), has been demonstrated in a high acceleration stress environment on human volunteer subjects. Acceleration stress was applied in the head-to-foot direction and is referred to as +Gz. The REG instrument divides the cephalic impedance waveform into two components: (1) a baseline impedance signal, Zb, that is referable to the bulk movement of blood in and out of the head, and (2) a pulsatile impedance waveform that is heart beat coincident. The REG waveform also contains information about cerebrospinal fluid (CSF) volume changes and shifts resulting from the application of acceleration stress. Blood and CSF shifts in and out of the cranial and spinal compartments impinge directly upon the overall function of the central nervous system. The high acceleration environment provides an ideal arena in which to noninvasively alter cephalic fluid volumes in order to obtain basic physiologic knowledge of importance to both aviation and clinical medicine. This information has been obtained in a noninvasive, safe, convenient, and unobtrusive manner on the Naval Air Development Center (NADC) human centrifuge. Using data derived from three different sets of human experiments conducted in a high +Gz environment have led to the characterization of the changes in the REG waveform that occur with increasing acceleration load. Alterations in the Zb waveform indicate its utility as an aid in determining the effectiveness of anti-G protective devices, such as reclining aircraft seats, and anti-G techniques, such as anti-G straining maneuvers. Use of the Zb waveform provides the first indirect (or direct) estimate of the bulk movement of blood under a +Gz load as predicted by the hydrostatic column theory of the physiological response in increasing acceleration load. An outline for animal and human experimentation necessary to develop a mathematical model to describe the changes in both vascular and CSF compartments is presented.
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Details
- Title
- Rheoencephalography in simulated aviation environment stress
- Creators
- Barry Scott Shender
- Contributors
- Stephen E. Dubin (Advisor) - Drexel University, Drexel University (1970-)
- Awarding Institution
- Drexel University
- Degree Awarded
- Doctor of Philosophy (Ph.D.)
- Publisher
- Drexel University; Philadelphia, Pennsylvania
- Number of pages
- xvii, 229 pages
- Resource Type
- Dissertation
- Language
- English
- Academic Unit
- Drexel University
- Other Identifier
- 991021889065604721