Kirsch K, Merke J, Hinghofer-Szalkay H
Pflugers Arch. 1980 Feb;383(3):195-201. doi: 10.1007/BF00587518.
In up to six different sides along the body axis during tilting manoeuvres, volume shifts into or out off superficial tissues were followed with a newly developed miniature plethysmograph. It was possible to localize a region where no or only minor volume changes during the tilt table experiments occurred. This region is identical with the Hydrostatic Indifferent Point (HIP) being localized below the apex of the heart in the upper third of abdominal vena cava. Above the HIP fluid is drained out off the tissues during assumption of upright posture whereas below the HIP fluid volume is pooled. The volume changes occurred in two phases. Within the first 5 s in the cephalad parts of the body a rapid decrease occurred, thereafter the volume remained unchanged or even increased; below the HIP within the first 5 s a large volume increase was followed by a slow continuous volume increment. The functional peculiarities of the low pressure system as a whole were visible studying only superficial shell tissues of the body with the non invasive miniature plethysmographic technique.
在倾斜动作过程中，沿着身体轴线最多六个不同的部位，使用新开发的微型体积描记器跟踪体积向浅表组织内或从浅表组织中移出的情况。在倾斜台实验期间，可以定位一个在该区域未发生或仅发生微小体积变化的区域。该区域与位于腹部上腔静脉心脏尖端下方的流体静压中性点（HIP）相同。在HIP上方，在采取直立姿势时，液体从组织中排出，而在HIP下方，液体体积会积聚。体积变化分两个阶段发生。在身体头侧部分的最初5秒内，体积迅速减少，此后体积保持不变甚至增加；在HIP下方，最初5秒内体积大幅增加，随后是缓慢持续的体积增加。仅通过非侵入性微型体积描记技术研究身体的浅表外壳组织，就可以看出整个低压系统的功能特性。
