PO结构上包括外围探头(包含1个光电探测器和2个发光二极管,如图1所示)和微处理器单元。常见的PO可发出波长为940nm的红外光和波长为660nm的红光。由图2可见,在这两个波长之下,HbO2和RHb吸光度比值间的差异最大,根据光电探测器探测结果可计算出SpO2。
图1. PO外围探头工作示意图
图2.各类血红蛋白吸收光谱曲线
图3.监测下手指末梢组织血管示意图(该图片转自协和八微信公众平台)
图4.指氧监测中的AC和DC
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作者:协和麻醉科 王瑾
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