Background

Correlation coefficients between blood pressure and cerebral oxygen saturation measured using near-infrared spectrometry may be used to derive the tissue oximetry index of cerebral autoregulation. Cerebral oxygen saturations demonstrate poor agreement between near-infrared spectrometers however it is unclear if measurements of autoregulation are similarly specific to the equipment used.

Methods

Cerebral oxygen saturation was monitored bilaterally in 74 healthy volunteers using both the FORE-SIGHT and EQUANOX monitors in random order. The tissue oximetry index was calculated during changes in blood pressure induced by isometric handgrip manoeuvres and the mean bias and limits of agreement were calculated.

Results

Tissue oximetry index measured by FORE-SIGHT was higher than EQUANOX (0.21 ± 0.16 versus 0.15 ± 0.17, P < 0.001) and limits of agreement were −0.24 to 0.36. Baseline cerebral oxygen saturation by FORE-SIGHT was lower than EQUANOX by 1.48% (CI95% 0.63–2.33) and limits of agreement ranged from −11.8% to 8.8%.

Conclusions

The substantial bias and wide limits of agreement for the tissue oximetry index as a measure of cerebral autoregulation indicate that values must be treated as specific to models of near-infrared spectrometers.

中文翻译：

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健康志愿者中脑血管自动调节的组织氧合指数：两种NIRS设备的比较。

背景

使用近红外光谱法测得的血压与脑血氧饱和度之间的相关系数可用于得出脑自动调节的组织血氧饱和度指数。脑血氧饱和度表明近红外光谱仪之间的一致性较差，但是尚不清楚自动调节的测量是否与所用设备类似。

方法

使用FORE-SIGHT和EQUANOX监护仪以随机顺序对74名健康志愿者的双侧脑氧饱和度进行了监测。在等距手柄操作引起的血压变化过程中计算组织血氧饱和度指数，并计算平均偏差和一致性极限。

结果

通过FORE-SIGHT测量的组织血氧饱和度指数高于EQUANOX（0.21±0.16对0.15±0.17，P <0.001），一致性极限为-0.24至0.36。通过FORE-SIGHT得出的基线脑血氧饱和度比EQUANOX低1.48％（CI95％0.63–2.33），一致极限范围为−11.8％至8.8％。

结论

组织血氧饱和度指数作为衡量大脑自动调节的指标存在很大的偏差和广泛的界限，这表明必须将这些值视为特定于近红外光谱仪的模型。