Extended-coverage-bladder G-suits can provide improved G-tolerance and high Gz foot pain

An extended coverage bladder (ECB) G-suit was evaluated on the DCIEM centrifuge against the current service G-suit (CSU-15/P) in two separate series of experiments. The ECB G-suit covered approximately 85% of the lower body measuring from the umbilicus and all five bladders completely encircled each leg and the lower trunk. The CSU-15/P G-suit covered approximately 30% of the lower body and its five bladders were located only over the frontal aspect of each leg and the lower trunk. The first series of experiments involved five subjects from the highly experienced DCIEM A-team. A standard gradual onset rate (GOR) run was used and suit testing order was counterbalanced across subjects.

The test condition G-tolerances are listed as mean +/- SEM; relaxed uninflated tolerances were 4.0 +/- 0.14 for the CSU-15/P suit vs. 4.1 +/- 0.09 for the ECB suit (ns, single tailed, paired t-test) while relaxed inflated tolerances were 4.7 +/- 0.19 for the CSU-15/P suit and 5.5 +/- 0.37 for the ECB suit (p = 0.02, single tailed, paired t-test). The straining tolerances were 8.1 +/- 0.44 for the CSU-15/P suit and 9.0 +/- 0.56 for the ECB suit (p = 0.01, single tailed, paired t-test). The second series involved nine subjects for the following three G-suit conditions; CSU-15/P, ECB with inflation limiters, and ECB with inflation limiters and foot bladders. Relaxed uninflated tolerances were 4.0 +/- 0.13, 4.0 +/- 0.08, and 3.9 +/- 0.10 (ns) while straining inflated tolerances were 9.4 +/- 0.48, 10.1 +/- 0.38 and 10.6 +/- 0.42, respectively (p = 0.01 between all three straining conditions, ANOVA with Scheffé F-test). The ECB G-suit with inflation limiters eliminated abdominal pain and discomfort.

The ECB G-suit provides improved G-tolerance for both inflated relaxed and straining exposures. Foot bladders eliminated high Gz foot pain and improved straining G-tolerance by about half a Gz. The efficacy of ECB G-suits should be evaluated when used in conjunction with positive pressure breathing. While the ultimate G-suit has yet to be conceived and will no doubt be part of an integrated life support system, ECB G-suits are a step in the right direction in the evolution of life support garmentry.