Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
Respir Physiol Neurobiol. 2009 Oct;169 Suppl 1:S59-62. doi: 10.1016/j.resp.2009.04.003. Epub 2009 Apr 9.
The decompression experienced due to the change in pressure from a space vehicle (1013hPa) to that in a suit for extravehicular activity (EVA) (386hPa) was simulated using a hypobaric chamber. Previous ground-based research has indicated around a 50% occurrence of both venous gas emboli (VGE) and symptoms of decompression illness (DCI) after similar decompressions. In contrast, no DCI symptoms have been reported from past or current space activities. Twenty subjects were studied using Doppler ultrasound to detect any VGE during decompression to 386hPa, where they remained for up to 6h. Subjects were supine to simulate weightlessness. A large number of VGE were found in one subject at rest, who had a recent arm fracture; a small number of VGE were found in another subject during provocation with calf contractions. No changes in exhaled nitric oxide were found that can be related to either simulated EVA or actual EVA (studied in a parallel study on four cosmonauts). We conclude that weightlessness appears to be protective against DCI and that exhaled NO is not likely to be useful to monitor VGE.
使用减压舱模拟了太空飞行器（1013hPa）到舱外活动服（EVA）（386hPa）压力变化引起的减压。之前的地面研究表明，在类似的减压后，静脉气体栓塞（VGE）和减压病（DCI）的发生率约为 50%。相比之下，过去或当前的太空活动都没有报告 DCI 症状。使用多普勒超声检测 20 名受试者在减压至 386hPa 期间是否有任何 VGE，他们在减压舱中停留长达 6 小时。受试者仰卧位以模拟失重。在一名最近手臂骨折的休息受试者中发现了大量 VGE；在另一名受试者进行小腿收缩诱发时发现了少量 VGE。未发现与模拟 EVA 或实际 EVA（在对四名宇航员进行的平行研究中进行了研究）相关的呼气一氧化氮变化。我们得出的结论是，失重似乎可以预防 DCI，而呼气一氧化氮不太可能用于监测 VGE。
