title: Dexmedetomidine anesthesia enhances spike generation during intra-operative electrocorticography: A promising adjunct for epilepsy surgery.
abstract: BACKGROUND
  Anesthetic-induced suppression of cortical electrical activity is a major concern during epilepsy surgery. Dexmedetomidine (Dex) has been recently evaluated in a few small series for its effect on the electrocorticographic spikes intra-operatively.
  
  
  METHODS
  In this prospective study, electrocorticogram (ECoG) was monitored during dexmedetomidine infusion in 34 patients (M:F=23:11, age=29.2 ± 10.9 years; duration of epilepsy=15.3 ± 8.9 years) undergoing anterior temporal lobe resection with amygdalo-hippocampectomy for drug-resistant mesial temporal lobe epilepsy (Right: 18, Left: 16). Anesthesia was induced with thiopental/propofol and maintained with oxygen-N2O-isoflurane. ECoG was recorded for 5 min after the end tidal MAC of N2O and isoflurane were decreased to zero; anesthesia was maintained with O2:Air=50:50, vecuronium and fentanyl. ECoG was recorded using a 4-contact strip electrode for: (a) 5 min prior to dexmedetomidine (PreDEX), (b) 5 min during dexmedetomidine infusion (DEX; 1 μg/kg) and (c) 5 min after stopping dexmedetomidine (PostDEX).
  
  
  RESULTS
  The ECoG spikes were manually counted in all the channels. The mean spike rate in the 2 channels with maximum spikes (MAX CH A and MAX CH B) was normalized to a 3-min duration. RM-ANOVA and post hoc comparison of three phases were used to compare the spike rates. The mean spike rate during Dex phase was higher compared to preDEX (MAX CH B: p=0.007 and MAX CH A: p=0.079) and PostDEX (MAX CH B: p=0.17, MAX CH A: p=0.79) phases. The spike rate increased in 67.6% patients, while 11.8% patients showed ≤ 25% reduction and 20.6% patients showed >25% reduction in spike frequency.
  
  
  CONCLUSIONS
  Dexmedetomidine is useful during intra-operative ECoG recording in epilepsy surgery as it enhances or does not alter spike rate in most of the cases, without any major adverse effects.
authors.affiliation: Department of Clinical Neuroscience, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India; Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India.
authors.forename: G
authors.initials: G
authors.lastname: Chaitanya
authors.affiliation: Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India. Electronic address: arivazhagan.a@gmail.com.
authors.forename: A
authors.initials: A
authors.lastname: Arivazhagan
authors.affiliation: Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India.
authors.forename: S
authors.initials: S
authors.lastname: Sinha
authors.affiliation: Department of Neuro Anesthesiology, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India.
authors.forename: K R Madhusudan
authors.initials: KR
authors.lastname: Reddy
authors.affiliation: Department of Biostatistics, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India.
authors.forename: K
authors.initials: K
authors.lastname: Thennarasu
authors.affiliation: Department of Neuroimaging and Interventional Radiology, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India.
authors.forename: R D
authors.initials: RD
authors.lastname: Bharath
authors.affiliation: Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India.
authors.forename: M Bhaskara
authors.initials: MB
authors.lastname: Rao
authors.affiliation: Department of Neurosurgery, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India.
authors.forename: B A
authors.initials: BA
authors.lastname: Chandramouli
authors.affiliation: Department of Neurology, National Institute of Mental Health and Neurosciences, Bangalore, Karnataka, India.
authors.forename: P
authors.initials: P
authors.lastname: Satishchandra
mesh_terms: D000328:Adult; D000777:Anesthetics; D001921:Brain / Q000187:drug effects / Q000503:physiopathology / Q000601:surgery; D020927:Dexmedetomidine; D004569:Electroencephalography / Q000379:methods*; D004827:Epilepsy / Q000503:physiopathology* / Q000601:surgery*; D005260:Female; D006801:Humans; D064795:Intraoperative Neurophysiological Monitoring / Q000379:methods*; D008297:Male; D019635:Neurosurgical Procedures / Q000379:methods; D011446:Prospective Studies
chemical_list: D000777:Anesthetics; D020927:Dexmedetomidine
keywords: Dexmedetomidine; Drug-resistant epilepsy; Electrocorticography; Mesial temporal sclerosis, Anesthesia