de Kock J P, Tarassenko L, Glynn C J, Hill A R
Department of Engineering Science, Oxford University, U.K.
IEEE Trans Biomed Eng. 1993 Aug;40(8):817-23. doi: 10.1109/10.238467.
Conventional transmission pulse oximetry is a noninvasive technique for the continuous monitoring of arterial oxygen saturation (SaO2) from peripheral vascular beds such as the finger tip or earlobe. In this paper we propose to exploit the unique transparency of the ocular media to make reflectance pulse oximetry measurements on the retinal fundus. This technique potentially offers significant advantages over conventional pulse oximetry, primarily the ability to monitor cerebral, as opposed to peripheral, oxygen saturation. We have developed an in vitro system to stimulate the retinal circulation and ocular optics. This system consists of a flexible cuvette located in a model eye and an extracorporeal blood circuit to stimulate arterial blood flow. The system was used to investigate the relationship between SaO2 and the R/IR ratio in reflectance pulse oximetry. To enable in vivo measurements to be made, we also modified a standard haptic contact lens to hold the pulse oximeter probe in front of the pupil. In a preliminary study, the lens was fitted to an awake volunteer and cardiac-synchronous signals were detected by the retinal pulse oximeter.
传统的透射式脉搏血氧测定法是一种用于连续监测来自外周血管床（如指尖或耳垂）的动脉血氧饱和度（SaO2）的非侵入性技术。在本文中，我们建议利用眼介质独特的透明度，在视网膜眼底进行反射式脉搏血氧测定。与传统脉搏血氧测定法相比，该技术可能具有显著优势，主要是能够监测大脑而非外周的血氧饱和度。我们开发了一种体外系统来模拟视网膜循环和眼光学。该系统由位于模型眼中的柔性比色皿和用于模拟动脉血流的体外血液回路组成。该系统用于研究反射式脉搏血氧测定中SaO2与R/IR比值之间的关系。为了能够进行体内测量，我们还对标准触觉隐形眼镜进行了改装，以便将脉搏血氧计探头固定在瞳孔前方。在一项初步研究中，将该隐形眼镜佩戴在一名清醒志愿者身上，视网膜脉搏血氧计检测到了心脏同步信号。
