title: Comparison of motor-evoked potentials monitoring in response to transcranial electrical stimulation in subjects undergoing neurosurgery with partial vs no neuromuscular block.
abstract: BACKGROUND
  There have been no evidence-based comparisons of motor-evoked potential (MEP) monitoring with no and partial neuromuscular block (NMB). We compared the effects of different levels of NMB including no NMB on MEP parameters.
  
  
  METHODS
  MEP-monitored 120 patients undergoing neurosurgery were enrolled. The patients were randomly allocated to four groups: Group A was to maintain two train-of-four (TOF) counts; Group B was to maintain a T(1)/Tc of 0.5; Group C was to maintain a T(2)/Tc of 0.5 (T(1,2), first or second twitch height of TOF; Tc, control twitch height); Group D did not maintain NMB. The mean MEP amplitude, coefficient of variation (CV), the incidence of spontaneous respiration or movement, the efficacy of MEP, and haemodynamic parameters were compared.
  
  
  RESULTS
  The median [inter-quartile range (IQR)] amplitudes of the left leg for Groups A, B, C, and D were 0.23 (0.15-0.57), 0.44 (0.19-0.79), 0.28 (0.15-0.75), and 0.75 (0.39-1.35) mV, respectively. The median (IQR) CVs of the left leg were 71.1 (56.9-88.8), 76.1 (54.2-93.1), 59.8 (48.6-95.6), and 25.2 (17.3-35.0), respectively. The differences between groups of the mean amplitudes of the left arm and both legs were statistically significant (Kruskal-Wallis test, P=0.011 for the left leg). For all limbs, the differences between groups of the CVs were significant (P<0.001, for the left leg). Other parameters were not different.
  
  
  CONCLUSIONS
  If NMB is used during MEP monitoring, a target T(2)/Tc of 0.5 is recommended. In terms of the MEP amplitude and variability, no NMB was more desirable than any level of partial NMB.
authors: Department of Anesthesiology and Pain Medicine, Samsung Medical Centre, Sungkyunkwan University School of Medicine, 50, Irwon-Dong, Seoul 135-710, Republic of Korea.
authors: W H
authors: WH
authors: Kim
authors: J J
authors: JJ
authors: Lee
authors: S M
authors: SM
authors: Lee
authors: M N
authors: MN
authors: Park
authors: S K
authors: SK
authors: Park
authors: D W
authors: DW
authors: Seo
authors: I S
authors: IS
authors: Chung
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000768:Anesthesia, General; D000771:Anesthesia, Intravenous; D062186:Arterial Pressure / Q000187:drug effects; D004558:Electric Stimulation / Q000379:methods*; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D007839:Functional Laterality / Q000502:physiology; D006339:Heart Rate / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D009068:Movement; D019148:Neuromuscular Blockade; D003473:Neuromuscular Nondepolarizing Agents; D019635:Neurosurgical Procedures / Q000379:methods*; D018401:Sample Size; D016896:Treatment Outcome; D014673:Vecuronium Bromide; D055815:Young Adult
chemical_list: D003473:Neuromuscular Nondepolarizing Agents; D014673:Vecuronium Bromide