Simulating study of cardiovascular response and +Gz protection afforded by extended coverage G-suit

By use of our newly developed mathematical model of human cardiovascular system based on previous works of Jaron et al. (1988) and Bai et al. (1992), computer simulation studies were performed to investigate the effect of bladder coverage and inflation schedule of anti-G suit on G tolerance and cardiovascular response with an aim to optimize the design of extended coverage anti-G suit. The simulation results have been shown to compare well with some centrifuge experiments. The study demonstrates that +Gz tolerance significantly enhanced with the extension of the G-suit bladder coverage and an increase of the slope of suit pressurization schedule. The G protection afforded by shifting upward the inflating cut-in point is largely dependent upon the inflation schedule adopted. Additional +Gz protection provided by the extension of the bladder coverage depends mainly upon the pressure transmission efficiency to the underlying tissues and vessels, while the relationship between the transmission efficiency and bladder coverage area may be exponential rather than linear. In addition, this study also demonstrates that a lowered abdominal bladder pressure to about half of that of leg bladder would not adversely impact G tolerance