title: Suppression of spinal and cortical somatosensory evoked potentials by desflurane anesthesia.
abstract: The effect of the volatile anesthetic desflurane on spinal and cortical somatosensory evoked potentials (SEPs) was examined in 11 Sprague-Dawley male rats. Platinum recording electrodes were placed stereotactically over the left somatosensory cortex and dorsal midline of the T11-12 spinal cord while the right posterior tibial nerve was stimulated at twice motor threshold. The effect of desflurane was examined at various concentrations ranging from 0.7 to 11.4% (2 MAC). Mean arterial blood pressure (MAP) decreased (p = 0.001) progressively with increasing end-tidal desflurane concentrations. Concentrations of 1.4% (1/4 MAC) and 2.8% (1/2 MAC) did not significantly affect the spinal SEP (SSEP) amplitude or the latency. With higher concentrations, there was a progressive decrease in amplitude of the cortical SEPs (CSEPs; p = 0.002) and SSEPs (p = 0.008). However, CSEP and SSEP latencies did not change. At 5.7% (1 MAC), three animals (33%) lost CSEPs while SSEPs remained intact. At 11.4% (2 MAC), the CSEPs were lost in all animals. Only one rat lost the SSEPs at the 2 MAC concentration of desflurane, indicating the resistance of the SSEPs to desflurane anesthesia. We conclude that desflurane anesthesia significantly alters the amplitude of SSEPs and CSEPs without a significant change in the peak latency.
authors.affiliation: Division of Neurosurgery, University of Missouri-Columbia 65212, USA.
authors.forename: S S
authors.initials: SS
authors.lastname: Haghighi
authors.forename: S J
authors.initials: SJ
authors.lastname: Sirintrapun
authors.forename: J C
authors.initials: JC
authors.lastname: Johnson
authors.forename: B P
authors.initials: BP
authors.lastname: Keller
authors.forename: J J
authors.initials: JJ
authors.lastname: Oro
mesh_terms: D000769:Anesthesia, Inhalation; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002540:Cerebral Cortex / Q000187:drug effects / Q000502:physiology*; D000077335:Desflurane; D005071:Evoked Potentials / Q000187:drug effects; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects*; D007530:Isoflurane / Q000031:analogs & derivatives* / Q000494:pharmacology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012121:Respiration, Artificial; D013116:Spinal Cord / Q000187:drug effects / Q000502:physiology*
chemical_list: D018685:Anesthetics, Inhalation; D000077335:Desflurane; D007530:Isoflurane