Evaluation of the Risk of Circulating Microbubbles Under Simulated Extravehicular Activities After Bed Rest 932220
This ground-based study compared the risk of microbubbles during decompression under simulated space extravehicular activities (EVA) after three days of six-degree head-down bed rest with three days of ambulatory control. Test subjects were exposed to a pressure of 44.8 kPa (6.5 psi), breathed 100% oxygen, and exercised at reduced pressure either in the supine (during experimental) or upright (control) position. Circulating microbubbles were monitored by a precordial Doppler ultrasound device, and were found in 52% (12/23) of control and 26% (6/23) of experimental exposures. Survival analysis using Cox proportional hazards regression showed that there was 0.22 times (95% confidence interval=0.07-0.68) reduction in the risk of high grade microbubbles after bed rest, compared to controls (p=0.004). This finding is of importance in evaluating the risk of DCS during EVA.
Citation: Vasantha Kumar, K., Powell, M., and Waligora, J., "Evaluation of the Risk of Circulating Microbubbles Under Simulated Extravehicular Activities After Bed Rest," SAE Technical Paper 932220, 1993, https://doi.org/10.4271/932220. Download Citation
K. Vasantha Kumar, Michael R. Powell, James M. Waligora
NASA Johnson Space Center
International Conference On Environmental Systems