In critically ill patients, direct knowledge of intracellular pO2 would allow for identification of cellular hypoxia, which when prolonged leads to organ failure. We have developed a visible–near-infrared optical system that noninvasively measures myoglobin saturation, which is directly related to intracellular pO2, from the surface of the skin. We used an animal model of graded hypoxia from low levels of inspired oxygen (n = 5) and verified that low intracellular pO2 is correlated with high steady-state serum lactate values. In addition, the pO2 gradient between arterial blood and inside muscle cells was 83 mm Hg at 21% O2, but fell to 24 mm Hg at 8% O2. Continuous myoglobin saturation measurement in skeletal muscle displayed the same trends as cerebral oxygenation with no lag in changes over time, demonstrating its relevance as a measure of systemic oxygenation.

中文翻译：

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使用可见-近红外光谱法在分级缺氧期间进行无创细胞氧合测量

在危重患者中，直接了解细胞内 pO2 可以识别细胞缺氧，如果长期缺氧会导致器官衰竭。我们开发了一种可见-近红外光学系统，可从皮肤表面无创测量肌红蛋白饱和度，肌红蛋白饱和度与细胞内 pO2 直接相关。我们使用了低水平吸入氧（n = 5）的分级缺氧动物模型，并证实低细胞内 pO2 与高稳态血清乳酸值相关。此外，动脉血和内部肌肉细胞之间的 pO2 梯度在 21% O2 时为 83 mm Hg，但在 8% O2 时降至 24 mm Hg。骨骼肌中连续肌红蛋白饱和度测量显示出与脑氧合相同的趋势，随时间的变化没有滞后，