title: Photoplethysmographic measurements from the esophagus using a new fiber-optic reflectance sensor.
abstract: A prototype fiber-optic reflectance-mode pulse oximetry sensor and measurement system is developed for the purposes of estimating arterial oxygen saturation in the esophagus. A dedicated probe containing miniature right-angled glass prisms coupled to light sources and a photodetector by means of optical fibers is designed and used to record photoplethysmographic (PPG) signals from the esophageal epithelium in anesthetized patients. The probe is inserted simply by an anesthesiologist in all cases, and signals are recorded successfully in all but one of 20 subjects, demonstrating that esophageal PPG signals can be reliably obtained. The mean value of the oxygen saturation recorded from the esophagus for all subjects is 94.0 ± 4.0%. These results demonstrate that SpO(2) may be estimated in the esophagus using a fiber-optic probe.
authors.affiliation: City University London, School of Engineering and Mathematical Sciences, Northampton Square, London, EC1V 0HB, United Kingdom. justin.phillips.1@city.ac.uk
authors.forename: Justin P
authors.initials: JP
authors.lastname: Phillips
authors.forename: Richard M
authors.initials: RM
authors.lastname: Langford
authors.forename: Serene H
authors.initials: SH
authors.lastname: Chang
authors.forename: Panayiotis A
authors.initials: PA
authors.lastname: Kyriacou
authors.forename: Deric P
authors.initials: DP
authors.lastname: Jones
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001026:Coronary Artery Bypass; D020701:Esophagoscopes; D004947:Esophagus / Q000098:blood supply*; D006801:Humans; D008875:Middle Aged; D055100:Optical Fibers; D010092:Oximetry / Q000295:instrumentation* / Q000706:statistics & numerical data; D017156:Photoplethysmography / Q000295:instrumentation* / Q000706:statistics & numerical data; D015203:Reproducibility of Results; D012815:Signal Processing, Computer-Assisted; D055815:Young Adult