Department of Pediatrics, University of Washington, Seattle, WA 98195, USA.
Anal Chim Acta. 2013 Jun 27;785:27-33. doi: 10.1016/j.aca.2013.05.003. Epub 2013 May 13.
We have developed a method to make real-time, continuous, noninvasive measurements of muscle oxygenation (Mox) from the surface of the skin. A key development was measurement in both the visible and near infrared (NIR) regions. Measurement of both oxygenated and deoxygenated myoglobin and hemoglobin resulted in a more accurate measurement of Mox than could be achieved with measurement of only the deoxygenated components, as in traditional near-infrared spectroscopy (NIRS). Using the second derivative with respect to wavelength reduced the effects of scattering on the spectra and also made oxygenated and deoxygenated forms more distinguishable from each other. Selecting spectral bands where oxygenated and deoxygenated forms absorb filtered out noise and spectral features unrelated to Mox. NIR and visible bands were scaled relative to each other in order to correct for errors introduced by normalization. Multivariate Curve Resolution (MCR) was used to estimate Mox from spectra within each data set collected from healthy subjects. A Locally Weighted Regression (LWR) model was built from calibration set spectra and associated Mox values from 20 subjects using 2562 spectra. LWR and Partial Least Squares (PLS) allow accurate measurement of Mox despite variations in skin pigment or fat layer thickness in different subjects. The method estimated Mox in five healthy subjects with an RMSE of 5.4%.
我们开发了一种从皮肤表面实时、连续、无创测量肌肉氧合（Mox）的方法。一个关键的发展是在可见和近红外（NIR）区域进行测量。测量氧合和去氧合肌红蛋白和血红蛋白，比传统近红外光谱（NIRS）中仅测量去氧合成分，能更准确地测量 Mox。使用相对于波长的二阶导数减少了散射对光谱的影响，也使氧合和去氧合形式彼此之间更易区分。选择氧合和去氧合形式吸收的光谱带，滤除与 Mox 无关的噪声和光谱特征。为了校正归一化引入的误差，相对 NIR 和可见波段进行缩放。多元曲线分辨（MCR）用于从健康受试者每个数据集内的光谱中估计 Mox。使用 2562 个光谱，从 20 个对象的校准集光谱和相关 Mox 值构建局部加权回归（LWR）模型。LWR 和偏最小二乘（PLS）允许在不同对象的皮肤色素或脂肪层厚度变化的情况下，准确测量 Mox。该方法在五名健康受试者中估计 Mox，其 RMSE 为 5.4%。
