title: The effects of propofol, small-dose isoflurane, and nitrous oxide on cortical somatosensory evoked potential and bispectral index monitoring in adolescents undergoing spinal fusion.
abstract: In this study we compared the effects of propofol, small-dose isoflurane, and nitrous oxide (N(2)O) on cortical somatosensory evoked potentials (SSEP) and bispectral index (BIS) monitoring in adolescents undergoing spinal fusion. Twelve patients received the following anesthetic maintenance combinations in a randomly determined order: treatment #1: isoflurane 0.4% + N(2)O 70% + O(2) 30%; treatment #2: isoflurane 0.6% + N(2)O 70% + O(2) 30%; treatment #3: isoflurane 0.6% + air + O(2) 30%; treatment #4: propofol 120 microg . kg(-1) . min(-1) + air + O(2) 30%. Cortical SSEP amplitudes measured during anesthesia maintenance with treatment #3 (isoflurane 0.6%/air) were more than those measured during maintenance with treatment #1 (isoflurane 0.4%/N(2)O 70%) (P < 0.0001) and treatment #2 (isoflurane 0.6%/N(2)O 70%) (P < 0.0052). Cortical SSEP amplitudes measured during treatment #4 (propofol 120 microg . kg(-1) . min(-1)/air) were more than treatment #1 (isoflurane 0.4%/N(2)O 70%) (P < 0.0001), treatment #2 (Iso 0.6%/N(2)O 70%) (P < 0.0007), and treatment #3 (isoflurane 0.6%/air) (P < 0.0191). In addition, average BIS values measured during treatments 1, 2, 3 and 4 were 62, 62, 61, and 44 respectively. Only treatment #4 (propofol 120 microg . kg(-1) . min(-1)/air) uniformly maintained BIS values less than 60. Our study demonstrates that propofol better preserves cortical SSEP amplitude measurement and provides a deeper level of hypnosis as measured by BIS values than combinations of small-dose isoflurane/N(2)O or small-dose isoflurane alone.
authors.affiliation: Departments of *Anesthesiology, †Neurology, ‡Orthopaedics, and §Biostatistics, Children's Hospital of New York, New York-Presbyterian Hospital, New York, New York.
authors.forename: Anthony J
authors.initials: AJ
authors.lastname: Clapcich
authors.forename: Ronald G
authors.initials: RG
authors.lastname: Emerson
authors.forename: David P
authors.initials: DP
authors.lastname: Roye
authors.forename: Hui
authors.initials: H
authors.lastname: Xie
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Gallo
authors.forename: Kathy C
authors.initials: KC
authors.lastname: Dowling
authors.forename: Brian
authors.initials: B
authors.lastname: Ramnath
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Heyer
mesh_terms: D000293:Adolescent; D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D002648:Child; D004569:Electroencephalography / Q000187:drug effects*; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects*; D005260:Female; D006801:Humans; D007530:Isoflurane; D008297:Male; D016343:Monitoring, Intraoperative; D009609:Nitrous Oxide; D015742:Propofol; D012600:Scoliosis / Q000601:surgery; D013123:Spinal Fusion
chemical_list: D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D007530:Isoflurane; D009609:Nitrous Oxide; D015742:Propofol