Ocular perfusion pressure is not reduced in response to lower body negative pressure.

IF 4.4 1区 物理与天体物理 Q1 MULTIDISCIPLINARY SCIENCES
Eric A Hall, Richard S Whittle, Ana Diaz-Artiles
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Abstract

Lower body negative pressure (LBNP) has been proposed as a countermeasure to mitigate the cephalad fluid shift occurring during spaceflight, which may be associated with the development of Spaceflight Associated Neuro-ocular Syndrome (SANS). This study quantifies the effect of LBNP on intraocular pressure (IOP), mean arterial pressure at eye level (MAPeye), and ocular perfusion pressure (OPP). Twenty-four subjects (12 male, 12 female) were subjected to graded LBNP in 0° supine and 15° head-down tilt (HDT) postures from 0 mmHg to -50 mmHg in 10 mmHg increments. IOP decreased significantly with LBNP pressure in 0° supine (by 0.7 ± 0.09 mmHg per 10 mmHg LBNP pressure, p < 0.001) and in 15° HDT (by 1.0 ± 0.095 mmHg per 10 mmHg of LBNP pressure, p < 0.001). MAPeye significantly decreased by 0.9 ± 0.4 mmHg per 10 mmHg of LBNP pressure in 0° supine (p = 0.016) but did not significantly change with LBNP in 15° HDT (p = 0.895). OPP did not significantly change with LBNP in 0° supine (p = 0.539) but it significantly increased in 15° HDT at 1.0 ± 0.3 mmHg per 10 mmHg of LBNP pressure (p = 0.010). Sex did not have a significant effect on OPP, MAPeye, or IOP in any condition. In 15° HDT, the reduction in IOP during increasing negative pressure, combined with the relatively constant MAPeye, led to the increase in OPP. Furthermore, results suggest that LBNP, while effective in reducing IOP, is not effective in reducing OPP across all postures investigated.

眼部灌注压不会因身体负压降低而降低。
下半身负压(LBNP)被认为是减轻太空飞行期间发生的头侧体液转移的一种对策,这种转移可能与太空飞行相关神经眼综合症(SANS)的发生有关。本研究量化了 LBNP 对眼压 (IOP)、眼球水平平均动脉压 (MAPeye) 和眼灌注压 (OPP) 的影响。24 名受试者(12 名男性,12 名女性)在 0° 仰卧位和 15° 头朝下后仰(HDT)姿势下接受分级 LBNP,从 0 mmHg 到 -50 mmHg,以 10 mmHg 为增量。0° 仰卧位时,眼压随 LBNP 压力的增加而明显下降(每 10 mmHg LBNP 压力下降 0.7 ± 0.09 mmHg,p 眼压随 0° 仰卧位时每 10 mmHg LBNP 压力下降 0.9 ± 0.4 mmHg 而明显下降(p = 0.016)),但 15° HDT 时,眼压随 LBNP 没有明显变化(p = 0.895)。在 0° 仰卧位时,OPP 随 LBNP 的变化不明显(p = 0.539),但在 15° HDT 时,OPP 明显增加,LBNP 压力每增加 10 mmHg,OPP 增加 1.0 ± 0.3 mmHg(p = 0.010)。在任何条件下,性别对 OPP、MAPeye 或 IOP 均无明显影响。在 15° HDT 中,负压增加时眼压降低,再加上 MAPeye 相对恒定,导致 OPP 增加。此外,研究结果表明,LBNP 虽然能有效降低眼压,但在所有调查姿势中都不能有效降低 OPP。
本文章由计算机程序翻译,如有差异,请以英文原文为准。
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来源期刊
npj Microgravity
npj Microgravity Physics and Astronomy-Physics and Astronomy (miscellaneous)
CiteScore
7.30
自引率
7.80%
发文量
50
审稿时长
9 weeks
期刊介绍: A new open access, online-only, multidisciplinary research journal, npj Microgravity is dedicated to publishing the most important scientific advances in the life sciences, physical sciences, and engineering fields that are facilitated by spaceflight and analogue platforms.
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