Schlegel-University of Waterloo Research Institute for Aging, Waterloo, Ontario, Canada.
Department of Kinesiology, University of Waterloo, Waterloo, Ontario, Canada.
Physiol Rep. 2022 Feb;10(3):e15179. doi: 10.14814/phy2.15179.
Non-contact coded hemodynamic imaging (CHI) is a novel wide-field near-infrared spectroscopy system which monitors blood volume by quantifying attenuation of light passing through the underlying vessels. This study tested the hypothesis that CHI-based jugular venous attenuation (JVA) would be larger in men, and change in JVA would be greater in men compared to women during two fluid shift challenges. The association of JVA with ultrasound-based cross-sectional area (CSA) was also tested. Ten men and 10 women completed three levels of head-down tilt (HDT) and four levels of lower body negative pressure (LBNP). Both JVA and CSA were increased by HDT and reduced by LBNP (all p < 0.001). Main effects of sex indicated that JVA was higher in men than women during both HDT (p = 0.003) and LBNP (p = 0.011). Interaction effects of sex and condition were observed for JVA during HDT (p = 0.005) and LBNP (p < 0.001). We observed moderate repeated-measures correlations (r ) between JVA and CSA in women during HDT (r = 0.57, p = 0.011) and in both men (r = 0.74, p < 0.001) and women (r = 0.66, p < 0.001) during LBNP. While median within-person correlation coefficients indicated an even stronger association between JVA and CSA, this association became unreliable for small changes in CSA. As hypothesized, JVA was greater and changed more in men compared to women during both HDT and LBNP. CHI provides a non-contact method of tracking large changes in internal jugular vein blood volume that occur with acute fluid shifts, but data should be interpreted in a sex-dependent manner.
非接触编码血流动力学成像（CHI）是一种新型的宽视场近红外光谱系统，通过量化穿过下面血管的光衰减来监测血容量。本研究检验了以下假设：在两种液体转移挑战中，基于 CHI 的颈内静脉衰减（JVA）在男性中更大，并且与女性相比，JVA 的变化更大。还测试了 JVA 与基于超声的横截面积（CSA）的相关性。10 名男性和 10 名女性完成了三个头低位倾斜（HDT）水平和四个下体负压（LBNP）水平。HDT 会增加 JVA 和 CSA，LBNP 则会降低 JVA 和 CSA（均 p<0.001）。性别主要效应表明，在 HDT 期间（p=0.003）和 LBNP 期间（p=0.011），JVA 均高于女性。在 HDT（p=0.005）和 LBNP（p<0.001）期间观察到性别和条件的交互效应。在女性进行 HDT 期间（r=0.57，p=0.011）和男性和女性进行 LBNP 期间（r=0.74，p<0.001 和 r=0.66，p<0.001），观察到 JVA 与 CSA 之间存在中等程度的重复测量相关性（r）。虽然个体内中位数相关系数表明 JVA 与 CSA 之间存在更强的关联，但 CSA 发生小变化时，这种关联变得不可靠。如假设所示，在 HDT 和 LBNP 期间，与女性相比，JVA 在男性中更大，变化更大。CHI 提供了一种非接触式方法来跟踪急性液体转移时内部颈静脉血容量的大变化，但数据应在性别依赖性的基础上进行解释。
