Young Andrew J, Karl James P, Berryman Claire E, Montain Scott J, Beidleman Beth A, Pasiakos Stefan M
U.S. Army Research Institute of Environmental Medicine, Natick, Massachusetts.
Oak Ridge Institute for Science and Education, Belcamp, Maryland.
Physiol Rep. 2019 Mar;7(6):e14051. doi: 10.14814/phy2.14051.
When sea-level (SL) residents rapidly ascend to high altitude (HA), plasma volume (PV) decreases. A quantitative model for predicting individual %∆PV over the first 7 days at HA has recently been developed from the measurements of %∆PV in 393 HA sojourners. We compared the measured %∆PV with the %∆PV predicted by the model in 17 SL natives living 21 days at HA (4300 m). Fasting hematocrit (Hct), hemoglobin (Hb) and total circulating protein (TCP) concentrations at SL and on days 2, 7, 13, and 19 at HA were used to calculate %∆TCP and %∆PV. Mean [95%CI] measured %∆PV on HA2, 7, 13 and 19 was -2.5 [-8.2, 3.1], -11.0 [-16.6, -5.5], -11.7 [-15.9, -7.4], and -16.8 [-22.2, -11.3], respectively. %∆PV and %∆TCP were positively correlated (P < 0.001) at HA2, 7, 13, and 19 (r = 0.77, 0.88, 0.78, 0.89, respectively). The model overpredicted mean [95% CI] decrease in %∆PV on HA2 (-12.5 [-13.9, -11.1]) and HA7 (-21.5 [-23.9, -19.1]), accurately predicted the mean decrease on HA13 (-14.3, [-20.0, -8.7]), and predicted a mean increase in %∆PV on HA19 (12.4 [-5.0, 29.8]). On HA2, 7, 13, and 19 only 2, 2, 6, and 1, respectively, of 17 individual measures of %∆PV were within 95% CI for predicted %∆PV. These observations indicate that PV responses to HA are largely oncotically mediated, vary considerably among individuals, and available quantitative models require refinement to predict %∆PV exhibited by individual sojourners.
当海平面（SL）居民迅速上升到高海拔（HA）地区时，血浆容量（PV）会减少。最近，通过对393名高海拔旅居者的PV变化百分比（%∆PV）进行测量，建立了一个预测高海拔地区前7天个体%∆PV的定量模型。我们将17名生活在高海拔（4300米）地区21天的海平面原住民的实测%∆PV与该模型预测的%∆PV进行了比较。利用海平面及高海拔地区第2、7、13和19天的空腹血细胞比容（Hct）、血红蛋白（Hb）和总循环蛋白（TCP）浓度来计算%∆TCP和%∆PV。在高海拔地区第2、7、13和19天，实测%∆PV的平均值[95%置信区间]分别为-2.5[-8.2, 3.1]、-11.0[-16.6, -5.5]、-11.7[-15.9, -7.4]和-16.8[-22.2, -11.3]。在高海拔地区第2、7、13和19天，%∆PV与%∆TCP呈正相关（P<0.001）（r分别为0.77、 0.88、0.78、0.89）。该模型高估了高海拔地区第2天（-12.5[-13.9, -11.1]）和第7天（-21.5[-23.9, -19.1]）%∆PV的平均下降幅度，准确预测了第13天的平均下降幅度（-14.3, [-20.0, -8.7]），并预测第19天高海拔地区%∆PV会平均增加（12.4[-5.0, 29.8]）。在高海拔地区第2、7、13和19天，17个个体%∆PV测量值中分别只有2、2、6和1个在预测%∆PV的95%置信区间内。这些观察结果表明，血浆容量对高海拔的反应主要由胶体渗透压介导，个体之间差异很大，现有的定量模型需要改进，以预测个体旅居者表现出的%∆PV。
