title: Monitoring cerebral oxygenation and local field potential with a variation of isoflurane concentration in a rat model.
abstract: We aimed to investigate experimentally how anesthetic levels affect cerebral metabolism measured by near-infrared spectroscopy (NIRS) and to identify a robust marker among NIRS parameters to discriminate various stages of anesthetic depth in rats under isoflurane anesthesia. In order to record the hemodynamic changes and local field potential (LFP) in the brain, fiber-optic cannulae and custom-made microelectrodes were implanted in the frontal cortex of the skull. The NIRS and LFP signals were continuously monitored before, during and after isoflurane anesthesia. As isoflurane concentration is reduced, the level of oxyhemoglobin and total hemoglobin concentrations of the frontal cortex decreased gradually, while deoxyhemoglobin increased. The reflectance ratio between 730nm and 850nm and burst suppression ratio (BSR) correspond similarly with the change of oxyhemoglobin during the variation of isoflurane concentration. These results suggest that NIRS signals in addition to EEG may provide a possibility of developing a new anesthetic depth index.
authors.affiliation: Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, South Korea; These authors contributed equally to this study.
authors.forename: Dong-Hyuk
authors.initials: DH
authors.lastname: Choi
authors.affiliation: Department of Pediatric Dentistry, School of Dentistry, Seoul National University, Seoul 03080, South Korea; These authors contributed equally to this study.
authors.forename: Teo Jeon
authors.initials: TJ
authors.lastname: Shin
authors.affiliation: Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, South Korea.
authors.forename: Seonghyun
authors.initials: S
authors.lastname: Kim
authors.affiliation: Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, South Korea.
authors.forename: Jayyoung
authors.initials: J
authors.lastname: Bae
authors.affiliation: Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, South Korea.
authors.forename: Dongrae
authors.initials: D
authors.lastname: Cho
authors.affiliation: Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, South Korea.
authors.forename: Jinsil
authors.initials: J
authors.lastname: Ham
authors.affiliation: Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, South Korea.
authors.forename: Ji-Young
authors.initials: JY
authors.lastname: Park
authors.affiliation: Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, South Korea.
authors.forename: Hyoung-Ihl
authors.initials: HI
authors.lastname: Kim
authors.affiliation: Department of Anesthesiology and Pain Medicine, Chonnam National University Medical School, Gwangju 61469, South Korea.
authors.forename: Seongwook
authors.initials: S
authors.lastname: Jeong
authors.affiliation: Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, South Korea; leebr@gist.ac.kr.
authors.forename: Boreom
authors.initials: B
authors.lastname: Lee
authors.affiliation: Department of Biomedical Science and Engineering, Gwangju Institute of Science and Technology (GIST), Gwangju 61005, South Korea; jaekim@gist.ac.kr.
authors.forename: Jae Gwan
authors.initials: JG
authors.lastname: Kim
keywords: (000.1430) Biology and medicine; (170.1460) Blood gas monitoring; (170.2655) Functional monitoring and imaging; (170.4580) Optical diagnostics for medicine