Fu Q, Iwase S, Niimi Y, Kamiya A, Kawanokuchi J, Cui J, Mano T
Department of Autonomic Neuroscience, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan.
J Gravit Physiol. 2001 Jul;8(1):P83-4.
The benefits of lower body positive pressure (LBPP) are generally accepted for clinical treatment in medical emergencies caused by massive bleeding to maintain the systemic blood pressure. They are also used by NASA post spaceflight for preventing orthostatic hypotension in the astronauts. However, controversy still exists concerning the mechanisms underlying LBPP benefits. The purpose of this study was to test the hypothesis that the baroreflex-mediated enhancement in sympathetic activity would be attenuated by LBPP during an orthostatic challenge in humans. Specifically, we studied 1) the sympathetic activity responses by the microneurographic technique, using direct intraneural measurement of muscle sympathetic nerve activity (MSNA); and 2) the contributions of preload and afterload to the chances in MSNA response during orthostasis on application of LBPP. To accomplish these issues, MSNA was recorded microneurographically along with noninvasive measurement of the cardiovascular variables in all the subjects during exposure to a 70 degrees HUT with 30-mm Hg LBPP.
下体正压（LBPP）在因大出血导致的医疗紧急情况中用于维持全身血压的临床治疗，其益处已得到普遍认可。美国国家航空航天局（NASA）在太空飞行后也使用它来预防宇航员的体位性低血压。然而，关于LBPP益处的潜在机制仍存在争议。本研究的目的是检验以下假设：在人体直立应激期间，LBPP会减弱压力反射介导的交感神经活动增强。具体而言，我们研究了：1）通过微神经ography技术，使用直接神经内测量肌肉交感神经活动（MSNA）来研究交感神经活动反应；2）在应用LBPP进行直立过程中，前负荷和后负荷对MSNA反应变化的影响。为解决这些问题，在所有受试者暴露于70度头高位倾斜试验并施加30毫米汞柱LBPP时，通过微神经ography记录MSNA，并同时进行心血管变量的无创测量。
