Wyle Integrated Science and Engineering, Houston, Texas, USA.
J Appl Physiol (1985). 2012 Feb;112(3):454-62. doi: 10.1152/japplphysiol.00557.2011. Epub 2011 Sep 8.
The transition to microgravity eliminates the hydrostatic gradients in the vascular system. The resulting fluid redistribution commonly manifests as facial edema, engorgement of the external neck veins, nasal congestion, and headache. This experiment examined the responses to modified Valsalva and Mueller maneuvers measured by cardiac and vascular ultrasound (ECHO) in a baseline steady state and under the influence of thigh occlusion cuffs available as a countermeasure device (Braslet cuffs).
Nine International Space Station crewmember subjects (expeditions 16-20) were examined in 15 experiment sessions 101 ± 46 days after launch (mean ± SD; 33-185). Twenty-seven cardiac and vascular parameters were obtained with/without respiratory maneuvers before and after tightening of the Braslet cuffs (162 parameter states/session). Quality of cardiac and vascular ultrasound examinations was assured through remote monitoring and guidance by investigators from the NASA Telescience Center in Houston, TX, and the Mission Control Center in Korolyov, Moscow region, Russia.
14 of 81 conditions (27 parameters measured at baseline, Valsalva, and Mueller maneuver) were significantly different when the Braslet was applied. Seven of 27 parameters were found to respond differently to respiratory maneuvers depending on the presence or absence of thigh compression.
Acute application of Braslet occlusion cuffs causes lower extremity fluid sequestration and exerts commensurate measurable effects on cardiac performance in microgravity. Ultrasound techniques to measure the hemodynamic effects of thigh cuffs in combination with respiratory maneuvers may serve as an effective tool in determining the volume status of a cardiac or hemodynamically compromised patient at the "microgravity bedside."
向微重力的转变消除了血管系统中的静压梯度。由此产生的液体再分配通常表现为面部水肿、颈外静脉充血、鼻塞和头痛。本实验通过心脏和血管超声（ECHO）检查，研究了在基线稳态和大腿压迫袖带（Braslet 袖带）作为对抗措施装置的影响下，对改良的瓦尔萨尔瓦和 Mueller 动作的反应。
在发射后 101 ± 46 天（平均值 ± 标准差；33-185），对 9 名国际空间站机组人员（任务 16-20）进行了 15 次实验。在 Braslet 袖带收紧前后，进行了 27 项心脏和血管参数的呼吸动作，共获得 27 项参数状态/次。通过休斯顿 NASA telescience 中心和莫斯科地区科罗廖夫任务控制中心的研究人员进行远程监测和指导，保证了心脏和血管超声检查的质量。
在 Braslet 应用时，81 种情况中的 14 种（基线、瓦尔萨尔瓦和 Mueller 动作时测量的 27 个参数）有显著差异。在有/无大腿压迫的情况下，有 7 个参数对呼吸动作的反应不同。
急性应用 Braslet 闭塞袖带会导致下肢液体潴留，并对微重力下的心脏功能产生相应的可测量影响。超声技术测量大腿袖带对呼吸动作的血液动力学影响，可能成为确定“微重力床边”心脏或血液动力学受损患者容量状态的有效工具。
