Hypoxia poses a serious threat to pilots. The aim of the study was to examine the efficacy of electrical bioimpedance (EBI) in detecting the onset of hypoxia in real time in a rabbit hypoxia model. Thirty-two New Zealand rabbits were divided equally into four groups (control group and 3 hypoxia groups, i.e. mild, moderate and severe). Hypoxia was induced by simulating various altitudes in the hypobaric oxygen chamber (3000 m, 5000 m and 8000 m). Both cerebral impedance and blood oxygen (SaO₂) were monitored continuously. Results showed that the cerebral impedance increased immediately during the period of increasing altitude and decreased quickly to the initial baseline at the phase of descending altitude. Moreover, the change of cerebral impedance in mild hypoxia group (3000 m) is significantly smaller than those in the other two groups (5000 m and 8000 m, P<0.05). The changes of cerebral impedance and SaO₂ were significantly correlated based on the total of measurement data (R²=0.628, P<0.001). Further, the agreement analysis performed with Bland-Altman and standardized residual plots exhibited high concordance between cerebral impedance and SaO₂. Receiver operator characteristic analysis manifested that the sensitivity, specificity and area under the curve using cerebral impedance for changes of SaO₂ >10% were 0.735, 0.826 and 0.845, respectively. These findings demonstrated that EBI could sensitively and accurately monitor changes of cerebral impedance induced by hypoxia, which might provide a potential tool for the real-time and non-invasive monitoring of hypoxic condition of pilots in flight for early identification of hypoxia.

中文翻译：

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使用电生物阻抗技术实时监测高海拔地区的缺氧：动物实验

缺氧严重威胁飞行员。这项研究的目的是检查电生物阻抗（EBI）在兔缺氧模型中实时检测缺氧发生的功效。将32只新西兰兔平均分为四组（对照组和3个低氧组，即轻度，中度和重度）。通过模拟低压氧舱中的各种高度（3000 m，5000 m和8000 m）来诱发缺氧。脑阻抗和血氧（SaO ₂）受到持续监控。结果表明，脑阻抗在海拔升高期间立即增加，在海拔下降阶段迅速下降至初始基线。此外，轻度缺氧组（3000 m）的脑阻抗变化明显小于其他两组（5000 m和8000 m，P <0.05）。根据测量数据的总和，脑阻抗和SaO _2的变化显着相关（R ² = 0.628，P <0.001）。此外，用Bland-Altman进行的一致性分析和标准化残差图显示了脑阻抗与SaO ₂之间的高度一致性。。接收者操作者特征分析表明，使用Saa ₂变化> 10％的脑阻抗曲线下的敏感性，特异性和面积分别为0.735、0.826和0.845。这些发现表明，EBI可以灵敏而准确地监测由缺氧引起的脑阻抗的变化，这可能为实时，无创地监测飞行中的飞行员的低氧状况提供了一种潜在的工具，以早期识别低氧。