Halliwill J R, Lawler L A, Eickhoff T J, Joyner M J, Mulvagh S L
Department of Anesthesiology, Mayo Medical School, Rochester, Minnesota, USA.
J Appl Physiol (1985). 1998 Feb;84(2):454-8. doi: 10.1152/jappl.1998.84.2.454.
Lower body negative pressure is frequently used to simulate orthostasis. Prior data suggest that venous pooling in abdominal or pelvic regions may have major hemodynamic consequences. Therefore, we developed a simple paradigm for assessing regional contributions to venous pooling during lower body negative pressure. Sixteen healthy men and women underwent graded lower body negative pressure protocols to 60 mmHg while wearing medical anti-shock trousers to prevent venous pooling under three randomized conditions: 1) no trouser inflation (control), 2) only the trouser legs inflated, and 3) the trouser legs and abdominopelvic region inflated. Without trouser inflation, heart rate increased 28 +/- 4 beats/min, mean arterial pressure fell -3 +/- 2 mmHg, and forearm vascular resistance increased 51 +/- 9 units at 60 mmHg lower body negative pressure. With inflation of either the trouser legs or the trouser legs and abdominopelvic region, heart rate and mean arterial pressure did not change during lower body negative pressure. By contrast, although the forearm vasoconstrictor response to lower body negative pressure was attenuated by inflation of the trouser legs (delta forearm vascular resistance 33 +/- 10 units, P < 0.05 vs. control), attenuation was greater with the inflation of the trouser legs and abdominopelvic region (delta forearm vascular resistance 16 +/- 5 units, P < 0.05 vs. control and trouser legs-only inflation). Thus the hemodynamic consequences of pooling in the abdominal and pelvic regions during lower body negative pressure appear to be less than in the legs in healthy individuals.
下体负压常被用于模拟直立位。先前的数据表明，腹部或盆腔区域的静脉淤积可能会产生重大的血流动力学后果。因此，我们开发了一种简单的范式，用于评估下体负压期间区域对静脉淤积的影响。16名健康男性和女性在穿着医用抗休克裤的情况下，接受了分级下体负压方案，将负压升至60 mmHg，在三种随机条件下进行，以防止静脉淤积：1）裤子不充气（对照组），2）仅裤腿充气，3）裤腿和腹部盆腔区域充气。在裤子不充气的情况下，下体负压为60 mmHg时，心率增加28±4次/分钟，平均动脉压下降-3±2 mmHg，前臂血管阻力增加51±9单位。当裤腿或裤腿与腹部盆腔区域充气时，下体负压期间心率和平均动脉压没有变化。相比之下，尽管裤腿充气会减弱前臂对下体负压的血管收缩反应（前臂血管阻力变化量为33±10单位，与对照组相比P<0.05），但裤腿和腹部盆腔区域充气时的减弱程度更大（前臂血管阻力变化量为16±5单位，与对照组和仅裤腿充气相比P<0.05）。因此，在健康个体中，下体负压期间腹部和盆腔区域静脉淤积的血流动力学后果似乎小于腿部。
