Accession Number : ADA320273

Title :   The Effects of Various Anti-G Suit Pressures and Positive Pressure Breathing on Lung Volumes as Measured by Spirometry at +1 Gz.

Descriptive Note : Final rept. Feb 90-Dec 95,

Corporate Author : SYSTEMS RESEARCH LABS INC DAYTON OH

Personal Author(s) : Tripp, Lloyd D., Jr. ; Larsen, Robert

PDF Url : ADA320273

Report Date : JUL 1996

Pagination or Media Count : 41

Abstract : Anti-G Suits have historically been evaluated using G-tolerance as the primary benchmark of a G-suit's effectiveness. One area which has been overlooked for over fifty years of G-suit design, is the effect of G-suit inflation on lung volumes. Lung inflation to about 75 percent of normal capacity is the key to producing the optimum intrathoracic pressure for performing the anti-G straining maneuver. This study evaluated three separate GH-suit designs, at +1 Gz and looked at the effect positive pressure breathing (PPB) had on maintaining lung volumes during G-suit inflations to 4, 6, and 8 psi. Lung volumes were measured using a microprocessor based spirometer. Results showed that the full pressure suit design (APS) had the smallest effect on inspiration. But in a comparison of the standard G-suit (trousers), the full coverage trousers (ATA0S) proved to be superior in design compared to the standard five bladder suit (CSU-13B/P). At suit pressures of 8 psi, Forced Inspiratory Vital Capacity (FIVC) percent change from baseline values for the APS, ATAGS, and CSU-13B/P were 80, 93, and 60% respectively. When PPB was added, FIVC values were 102, 66, and 46% respectively. These data show that the addition of PPB with anti-G suit trousers becomes a liability to lung function while the full pressure suit condition benefits by the addition of PPB. The use of pulmonary function testing as a means of determining the effect G-suit inflation has on lung volumes may prove to be ve useful in designing and evaluating the next generation of anti-G protection ensembles.

Descriptors :   *LUNG, *G SUITS, *RESPIRATION, *TOLERANCES(PHYSIOLOGY), *BREATHING APPARATUS, VOLUME, OPTIMIZATION, MICROPROCESSORS, BASE LINES, PRESSURE, STANDARDS, MANEUVERS, VALUE, THORAX, CLOTHING, PRESSURE BREATHING, SPIROMETRY.

Subject Categories : Anatomy and Physiology
      Stress Physiology
      Life Support Systems

Distribution Statement : APPROVED FOR PUBLIC RELEASE