title: Characterization of the near infrared absorption spectra of cytochrome aa3 and haemoglobin for the non-invasive monitoring of cerebral oxygenation.
abstract: Near infrared (IR) spectroscopy can give continuous, direct information about cerebral oxygenation in vivo by providing signals from oxygenated and deoxygenated haemoglobin and cytochrome aa3. Due to a lack of precise spectral information and uncertainties about optical path length it has previously been impossible to quantify the data. We have therefore obtained the cytochrome aa3 spectrum in vivo from the brains of rats after replacing the blood with a fluorocarbon substitute. Near infrared haemoglobin spectra were also obtained, at various oxygenation levels, from cuvette studies of lysed human red blood cells. Estimates of optical path length have been obtained. The data were used to construct an algorithm for calculating the changes in oxygenated and deoxygenated haemoglobin and oxygenated cytochrome aa3 in tissue from changes in near IR absorption.
authors.affiliation: Physiology Department, University College London, U.K.
authors.forename: S
authors.initials: S
authors.lastname: Wray
authors.forename: M
authors.initials: M
authors.lastname: Cope
authors.forename: D T
authors.initials: DT
authors.lastname: Delpy
authors.forename: J S
authors.initials: JS
authors.lastname: Wyatt
authors.forename: E O
authors.initials: EO
authors.lastname: Reynolds
mesh_terms: D000818:Animals; D001802:Blood Substitutes; D001923:Brain Chemistry; D003576:Electron Transport Complex IV / Q000032:analysis*; D006452:Hemoglobinometry / Q000379:methods*; D008297:Male; D010100:Oxygen / Q000378:metabolism*; D010108:Oxyhemoglobins / Q000032:analysis*; D051381:Rats; D011919:Rats, Inbred Strains; D013055:Spectrophotometry, Infrared
chemical_list: D001802:Blood Substitutes; D010108:Oxyhemoglobins; D003576:Electron Transport Complex IV; D010100:Oxygen