Cardiovascular responses with standard and extended bladder coverage G-suits during rapid decompression

This study compared the cardiovascular responses of subjects exposed to 60,000 ft. rapid decompressions while wearing the Combined Advanced Technology Enhanced Design "G" Ensemble (COMBAT EDGE or CE) and the Tactical Life Support System (TLSS). Eight subjects were rapidly decompressed from 22,500 ft (6,858 m) to 60,000 ft (18,288 m), once wearing the CE ensemble and once wearing the TLSS ensemble. There were significant differences in heart rate, stroke volume, cardiac index, and mean arterial pressure (p < 0.0001), due to garment type, with TLSS providing better cardiovascular support. Oxygen saturation did not decrease to the same degree with CE as with TLSS (p < 0.0001). Both TLSS and CE provided sufficient physiological support to maintain oxygen saturations above 65% during the 3-min exposures to 60,000 ft altitude. Short-term physiological support at higher altitudes with greater PPB levels or longer duration excursions at 60,000 ft may not be possible without the greater G-suit bladder coverage and cardiovascular support provided by TLSS-type garments.