Kyriacou P A
School of Engineering and Mathematical Sciences, City University, London EC1V 0HB, UK.
Physiol Meas. 2006 Jan;27(1):R1-35. doi: 10.1088/0967-3334/27/1/R01. Epub 2005 Nov 29.
Pulse oximetry has been one of the most significant technological advances in clinical monitoring in the last two decades. Pulse oximetry is a non-invasive photometric technique that provides information about the arterial blood oxygen saturation (SpO(2)) and heart rate, and has widespread clinical applications. When peripheral perfusion is poor, as in states of hypovolaemia, hypothermia and vasoconstriction, oxygenation readings become unreliable or cease. The problem arises because conventional pulse oximetry sensors must be attached to the most peripheral parts of the body, such as finger, ear or toe, where pulsatile flow is most easily compromised. Since central blood flow may be preferentially preserved, this review explores a new alternative site, the oesophagus, for monitoring blood oxygen saturation by pulse oximetry. This review article presents the basic physics, technology and applications of pulse oximetry including photoplethysmography. The limitations of this technique are also discussed leading to the proposed development of the oesophageal pulse oximeter. In the majority, the report will be focused on the description of a new oesophageal photoplethysmographic/SpO(2) probe, which was developed to investigate the suitability of the oesophagus as an alternative monitoring site for the continuous measurement of SpO(2) in cases of poor peripheral circulation. The article concludes with a review of reported clinical investigations of the oesophageal pulse oximeter.
脉搏血氧饱和度测定法是过去二十年来临床监测领域最重要的技术进步之一。脉搏血氧饱和度测定法是一种非侵入性的光度技术,可提供有关动脉血氧饱和度(SpO₂)和心率的信息,具有广泛的临床应用。当外周灌注不良时,如在低血容量、体温过低和血管收缩状态下,氧合读数会变得不可靠或停止。出现这个问题的原因是传统的脉搏血氧饱和度测定传感器必须附着在身体最外周的部位,如手指、耳朵或脚趾,而这些部位的搏动血流最容易受到影响。由于中心血流可能会优先得到保留,因此本综述探讨了一个新的替代部位——食管,用于通过脉搏血氧饱和度测定法监测血氧饱和度。这篇综述文章介绍了脉搏血氧饱和度测定法(包括光电容积脉搏波描记法)的基本物理原理、技术和应用。还讨论了该技术的局限性,从而提出了食管脉搏血氧仪的开发。在大多数情况下,报告将重点描述一种新的食管光电容积脉搏波描记法/SpO₂探头,该探头旨在研究在周围循环不良的情况下,食管作为连续测量SpO₂的替代监测部位的适用性。文章最后回顾了已报道的食管脉搏血氧仪的临床研究。