title: Microelectrode recording (MER) findings during sleep-awake anesthesia using dexmedetomidine in deep brain stimulation surgery for Parkinson's disease.
abstract: OBJECTIVE
  The preferred choice of anesthesia for deep brain stimulation (DBS) has been local anesthesia due to the need of patients' cooperation during the procedure, and concern on the interference of sedatives on microelectrode recording (MER) results. However, local anesthesia during the whole procedure may be impossible in some patients due to uncontrolled anxiety, fear, delirium or exhaustion. Therefore, sedative drugs have been used for DBS, but findings of MER during the procedures have not been reported in detail, especially in the globus pallidus internus (GPi). We introduce our experience using 'asleep-awake' technique by dexmedetomidine (DEX) anesthesia with MER findings during DBS in idiopathic Parkinson's disease (IPD) patients.
  
  
  METHODS
  Data from 14 different subcortical nuclei from 8 consecutive IPD patients whom had DBS at the GPi (6 patients) and subthalamic nucleus (STN) (2 patients) were retrospectively reviewed. We used continuous DEX and intermittent small boluses of propofol during the painful procedure ('asleep phase'), accompanied with continuous intraoperative monitorings of bispectral index (BIS) and modified observer's assessment of sedation (MOAA/S). Then sedatives were discontinued during MER recording ('awake phase'). Characteristic findings and firing rates of neurons were analyzed and compared to those from other 6 patients who underwent surgery under local anesthesia.
  
  
  RESULTS
  All patients were satisfactorily sedated using this technique without any respiratory or hemodynamic complications. Characteristics of spike activities of each nucleus were inspected and analyzed quantitatively. We could inspect changes of spike activities according to level of patients' consciousness in some cases, but the localizing value was good to decide the target in all cases. Firing rates of group whom sedatives were given during asleep phase ('sedatives') were significantly lower than those of group under local anesthesia ('no sedative'). Intraoperative length of target nuclei, postoperative imaging and postoperative changes of UPDRS III score indicated satisfactory outcome.
  
  
  CONCLUSIONS
  We concluded that though MER findings may change during DEX-based monitored 'sleep-awake' anesthesia, it did not affect the results of target localization for the clinical purpose. However, it should be considered that use of sedatives before MER could result in changes of firing rate and pattern depending on the patient's state of consciousness.
authors.affiliation: Department of Neurosurgery, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Republic of Korea.
authors.forename: Woo-Keun
authors.initials: WK
authors.lastname: Kwon
authors.affiliation: Department of Neurosurgery, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Republic of Korea. Electronic address: jhkimns@gmail.com.
authors.forename: Jong Hyun
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Neurosurgery, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Republic of Korea.
authors.forename: Ji-Hye
authors.initials: JH
authors.lastname: Lee
authors.affiliation: Department of Pain and Anesthesiology, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Republic of Korea.
authors.forename: Byung-Gun
authors.initials: BG
authors.lastname: Lim
authors.affiliation: Department of Pain and Anesthesiology, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Republic of Korea.
authors.forename: Il-ok
authors.initials: IO
authors.lastname: Lee
authors.affiliation: Department of Neurology, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Republic of Korea.
authors.forename: Seong Beom
authors.initials: SB
authors.lastname: Koh
authors.affiliation: Department of Neurosurgery, Korea University Guro Hospital, Korea University College of Medicine, Seoul, Republic of Korea.
authors.forename: Taek Hyun
authors.initials: TH
authors.lastname: Kwon
mesh_terms: D000368:Aged; D000772:Anesthesia, Local / Q000379:methods*; D046690:Deep Brain Stimulation / Q000379:methods*; D020927:Dexmedetomidine / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D006993:Hypnotics and Sedatives / Q000008:administration & dosage; D008297:Male; D008839:Microelectrodes; D008875:Middle Aged; D010300:Parkinson Disease / Q000503:physiopathology / Q000628:therapy*; D012189:Retrospective Studies; D012890:Sleep / Q000187:drug effects / Q000502:physiology; D014851:Wakefulness / Q000187:drug effects* / Q000502:physiology
chemical_list: D006993:Hypnotics and Sedatives; D020927:Dexmedetomidine
keywords: Deep brain stimulation; Dexmedetomidine; Microelectrode recording; Parkinson’s disease