Pulse oximetry and photoplethysmographic waveform analysis of the esophagus and bowelPhillips, Justin Pa; Kyriacou, Panayiotis Ab; Jones, Deric Pb; Shelley, Kirk Hc; Langford, Richard MaCurrent Opinion in Anesthesiology: December 2008 - Volume 21 - Issue 6 - p 779–783 doi: 10.1097/ACO.0b013e328317794d Technology, education and training: Edited by Kirk Shelley Abstract Author Information Purpose of review This article reviews the development of novel reflectance pulse oximetry sensors for the esophagus and bowel, and presents some of the techniques used to analyze the waveforms acquired with such devices. Recent findings There has been much research in recent years to expand the utility of pulse oximetry beyond the simple measurement of arterial oxygen saturation from the finger or earlobe. Experimental sensors based on reflectance pulse oximetry have been developed for use in internal sites such as the esophagus and bowel. Analysis of the photoplethysmographic waveforms produced by these sensors is beginning to shed light on some of the potentially useful information hidden in these signals. Summary The use of novel reflectance pulse oximetry sensors has been successfully demonstrated. Such sensors, combined with the application of more advanced signal processing, will hopefully open new avenues of research leading to the development of new types of pulse oximetry-based monitoring techniques. aAnaesthetic Laboratory, St Bartholomew's Hospital, UK bSchool of Engineering and Mathematical Sciences, City University, London, UK cDepartment of Anesthesiology, Yale University School of Medicine, New Haven, Connecticut, USA Correspondence to Justin Phillips, Anaesthetic Laboratory, St Bartholomew's Hospital, West Smithfield, London EC1A 7BE, UK Tel: +44 207 601 7527; e-mail: firstname.lastname@example.org © 2008 Lippincott Williams & Wilkins, Inc.