Sanni Adeola A, McCully Kevin K
Department of Kinesiology, University of Georgia, Athens, GA 30602, USA.
J Funct Morphol Kinesiol. 2019 May 26;4(2):28. doi: 10.3390/jfmk4020028.
Near-infrared spectroscopy (NIRS) uses the relative absorption of light at 850 and 760 nm to determine skeletal muscle oxygen saturation. Previous studies have used the ratio of both signals to report muscle oxygen saturation.
The purpose of this pilot study is to assess the different approaches used to represent muscle oxygen saturation and to evaluate the pulsations of oxygenated hemoglobin/myoglobin (Oheme) and deoxygenated hemoglobin/myoglobin (Heme) signals.
Twelve participants, aged 20-29 years, were tested on the forearm flexor muscles using continuous-wave NIRS at rest. Measurements were taken during 2-3 min rest, physiological calibration (5 min ischemia), and reperfusion. Ten participants were included in the study analysis.
There was a significant difference in pulse size between Oheme and Heme signals at the three locations ( < 0.05). Resting oxygen saturation was 58.8% + 9.2%, 69.6% + 3.9%, and 89.2% + 6.9% when calibrated using Oheme, the tissue oxygenation/saturation index (TSI), and Heme, respectively.
The difference in magnitude of Oheme and Heme pulses with each heartbeat might suggest different anatomical locations of these signals, for which calibrating with just one of the signals instead of the ratio of both is proposed. Calculations of physiological calibration must account for increased blood volume in the tissue because of the changes in blood volume, which appear to be primarily from the Oheme signal. Resting oxygen levels calibrated with Heme agree with theoretical oxygen saturation.
近红外光谱法（NIRS）利用850纳米和760纳米处光的相对吸收来测定骨骼肌氧饱和度。以往的研究使用这两种信号的比值来报告肌肉氧饱和度。
本初步研究的目的是评估用于表示肌肉氧饱和度的不同方法，并评估氧合血红蛋白/肌红蛋白（Oheme）和脱氧血红蛋白/肌红蛋白（Heme）信号的搏动情况。
12名年龄在20 - 29岁的参与者，在静息状态下使用连续波近红外光谱法对其前臂屈肌进行测试。在静息2 - 3分钟、生理校准（5分钟缺血）和再灌注期间进行测量。10名参与者纳入研究分析。
在三个位置，Oheme和Heme信号的脉冲大小存在显著差异（<0.05）。分别使用Oheme、组织氧合/饱和度指数（TSI）和Heme进行校准时，静息氧饱和度分别为58.8%±9.2%、69.6%±3.9%和89.2%±6.9%。
每次心跳时Oheme和Heme脉冲大小的差异可能表明这些信号的解剖位置不同，为此建议仅用其中一种信号而非两者的比值进行校准。生理校准的计算必须考虑到由于血容量变化导致的组织血容量增加，血容量变化似乎主要来自Oheme信号。用Heme校准的静息氧水平与理论氧饱和度相符。
