坐位下体负压对人体脑血管循环的影响  

Effects of lower body negative pressure in upright seated position on circulation of human cerebral blood vessel

作　　者：韩文强[1] 胡文东[1] 马进[1] 马瑞山[2] 

机构地区：[1]第四军医大学航空航天医学系航空航天医学工程研究室,陕西西安710033 [2]第四军医大学航空航天医学系航空航天生理学教研室,陕西西安710033

出　　处：《第四军医大学学报》2004年第13期1194-1197,共4页Journal of the Fourth Military Medical University

摘　　要：目的 :探讨坐位下体负压 (U LBNP)对人体脑血管循环的影响 .方法 :1 5名健康青年男性在 - 4 .0 0kPa(- 30mmHg) ,- 6 .6 7kPa (- 5 0mmHg)U LBNP下 ,分别测量负压前、负压暴露 0 .5 ,1 ,2 ,3,4 ,5min和卸压后 1 ,3,5min的大脑中动脉的搏动指数 (PI)、阻力指数 (RI)、血流速度 (vMCA)及主观症状和客观体征 .以负压前 5min测量的结果作为对照 .结果 :在 - 4 .0 0kPaU LBNP作用下 ,PI,RI无明显改变 ,vMCA在负压作用 4 ,5min时减慢 (P <0 .0 5 ) .在 - 6 .6 7kPaU LBNP作用下 ,PI,RI在 4 ,5min时增大 (P <0 .0 5 ) ;vMCA在负压作用2 ,3min时减慢 (P <0 .0 5 ) ,在 4 ,5min时显著减慢 (P <0 .0 1 ) ;卸压后 1minvMCA尚未恢复 (P <0 .0 5 ) ,随后恢复至对照水平 ;主观症状增多 ,客观体征明显 .结论 :LBNP造成血液在下肢淤积 ,使大脑中动脉PI和RI升高 ,vMCA减慢 ,引起大脑血供减少 。AIM: To investigate the effects of lower body negative pressure (LBNP) in the upright seated position on the circulation of humancerebral blood vessel. METHODS: Pulsatility index (PI), resistive index (RI), blood flow velocity in middle cerebrum ( v MCA ) were measured in 15 healthy young men. Subjective symptoms and objective physical signs were measured at 0.5, 1, 2, 3 and 4, 5 min during U LBNP and 1, 3 and 5 min after -4.00 kPa (-30 mmHg) and -6.67 kPa (-50 mmHg) U LBNP, respectively in upright seated position. At five minutes before the experiments, the subjects were tested and the data recorded were used as controls. RESULTS: Under -4.00 kPa U LBNP, v MCA slowed down at 4 and 5 min during U LBNP ( P <0.05) and there were no significant changes in PI and RI. Under -6.67 kPa U LBNP, PI and RI increased at 4 and 5 min during U LBNP ( P <0.05), v MCA began to slow down at 2 and 3 min during U LBNP ( P <0.05), and at 4 and 5 min, v MCA decelerated significantly during U LBNP ( P < 0.01). At 1 min after the release of U LBNP, v MCA did not recover ( P <0.05), after which, it recovered to the control level. Subjective symptoms increased and objective physical signs were obvious. CONCLUSION: LBNP can cause blood pooling in lower body, and as a result, PI and RI increase while v MCA decreases, which may decrease the brain blood volume and weaken the function of cerebral circulation.

关 键 词：下身负压 经颅多普勒超声检查 脑血管循环 搏动指数 血流速度 

分 类 号：R852.21[医药卫生—航空、航天与航海医学]