Vasomotion is defined as a spontaneous local oscillation in vascular tone whose function is unclear but may have a beneficial effect on tissue oxygenation. Optical reflectance spectroscopy and laser Doppler fluximetry provide unique insights into the possible mechanisms of vasomotion in the cutaneous microcirculation through the simultaneous measurement of changes in concentration of oxyhemoglobin ([HbO(2)]), deoxyhemoglobin ([Hb]), and mean blood saturation (S(mb)O(2)) along with blood volume and flux. The effect of vasomotion at frequencies <0.02 Hz attributed to endothelial activity was studied in the dorsal forearm skin of 24 healthy males. Fourier analysis identified periodic fluctuations in S(mb)O(2) in 19 out of 24 subjects, predominantly where skin temperatures were >29.3 degrees C (X(2) = 6.19, P < 0.02). A consistent minimum threshold in S(mb)O(2) (mean: 39.4%, range: 24.0-50.6%) was seen to precede a sudden transient surge in flux, inducing a fast rise in S(mb)O(2). The integral increase in flux correlated with the integral increase in [HbO(2)] (Pearson's correlation r(2) = 0.50, P < 0.001) and with little change in blood volume suggests vasodilation upstream, responding to a low S(mb)O(2) downstream. This transient surge in flux was followed by a sustained period where blood volume and flux remained relatively constant and a steady decrease in [HbO(2)] and equal and opposite increase in [Hb] was considered to provide a measure of oxygen extraction. A measure of this oxygen extraction has been approximated by the mean half-life of the decay in S(mb)O(2) during this period. A comparison of the mean half-life in the 8 normal subjects [body mass index (BMI) <26.0 kg/m(2)] of 12.2 s and the 11 obese subjects (BMI >29.5 kg/m(2)) of 18.8 s was statistically significant (Mann Whitney, P < 0.004). The S(mb)O(2) fluctuated spontaneously in this saw tooth manner by an average of 9.0% (range 4.0-16.2%) from mean S(mb)O(2) values ranging from 30 to 52%. These observations support the hypothesis that red blood cells may act as sensors of local tissue hypoxia, through the oxygenation status of the hemoglobin, and initiate improved local perfusion to the tissue through hypoxic vasodilation.
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机译：血管舒缩定义为血管性疾病的自发性局部振荡，其功能尚不清楚，但可能对组织的充氧有有益作用。光学反射光谱法和激光多普勒通量法通过同时测量氧合血红蛋白（[HbO（2）]），脱氧血红蛋白（[Hb]）和平均血液饱和度的变化，提供了对皮肤微循环中血管运动的可能机制的独特见解（S（mb）O（2））以及血液量和流量。在24位健康男性的前臂背侧皮肤中研究了血管内皮运动在<0.02 Hz频率下对血管内皮细胞的影响。傅里叶分析确定了24名受试者中19名的S（mb）O（2）的周期性波动，主要是皮肤温度> 29.3摄氏度（X（2）= 6.19，P <0.02）。观察到S（mb）O（2）中一致的最小阈值（平均值：39.4％，范围：24.0-50.6％）先于通量的突然瞬变激增，导致S（mb）O（2）迅速上升。 。通量的积分增加与[HbO（2）]的积分增加相关（Pearson相关r（2）= 0.50，P <0.001），并且血容量变化很小，表明上游血管舒张，对低S（mb）有反应O（2）下游。通量的这种瞬态激增之后是一个持续的时期，在此期间血量和通量保持相对恒定，并且[HbO（2）]的稳定下降和[Hb]的相等和相反的增长被认为是提供氧气提取的一种措施。通过此期间S（mb）O（2）衰减的平均半衰期，可以估算出这种氧气的提取量。比较8名正常受试者（体重指数（BMI）<26.0 kg / m（2））为12.2 s和11名肥胖受试者（BMI> 29.5 kg / m（2））为18.8的平均半衰期s具有统计学意义（Mann Whitney，P <0.004）。 S（mb）O（2）以这种锯齿状方式自发波动，从30％至52％的平均S（mb）O（2）值平均波动9.0％（4.0-16.2％）。这些观察结果支持以下假设：红细胞可以通过血红蛋白的氧合状态充当局部组织缺氧的传感器，并通过缺氧性血管舒张而引发对组织的改善的局部灌注。
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