TY - JOUR N2 - We report the use of a novel hybrid near-infrared spectrometer for the measurement of optical scattering, pathlength and chromophore concentration in critically ill patients with brain injury. Ten mechanically ventilated patients with acute brain injury were studied. In addition to standard neurointensive care monitoring, middle cerebral artery flow velocity, brain lactate-pyruvate ratio (LPR) and brain tissue oxygen tension were monitored. The patients were subjected to graded normobaric hyperoxia (NBH), with the inspired fraction of oxygen increased from baseline to 60% then 100%. NBH induced significant changes in the concentrations of oxyhaemoglobin, deoxyhaemoglobin and oxidised-reduced cytochrome c oxidase; these were accompanied by a corresponding reduction in brain LPR and increase in brain tissue oxygen tension. No significant change in optical scattering or pathlength was observed. These results suggest that the measurement of chromophore concentration in the injured brain is not confounded by changes in optical scattering or pathlength and that NBH induces an increase in cerebral aerobic metabolism. EP - 72 UR - http://dx.doi.org/10.1007/978-1-4614-4989-8_10 ID - discovery1361523 Y1 - 2013/// SN - 0065-2598 TI - Normobaric hyperoxia does not change optical scattering or pathlength but does increase oxidised cytochrome C oxidase concentration in patients with brain injury. AV - public JF - Adv Exp Med Biol A1 - Ghosh, A A1 - Tachtsidis, I A1 - Kolyva, C A1 - Highton, D A1 - Elwell, C A1 - Smith, M KW - Adult KW - Aged KW - Brain Injuries KW - Cerebrovascular Circulation KW - Electron Transport Complex IV KW - Female KW - Hemoglobins KW - Humans KW - Hyperoxia KW - Lactic Acid KW - Male KW - Middle Aged KW - Monitoring KW - Physiologic KW - Oxidation-Reduction KW - Oxygen KW - Oxyhemoglobins KW - Pyruvic Acid KW - Spectroscopy KW - Near-Infrared KW - Young Adult VL - 765 N1 - © Springer Science+Business Media New York 2013. This article is published with open access at Springerlink.com. This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited. SP - 67 ER -