title: Electromyographic response of facial nerve stimulation under different levels of neuromuscular blockade during middle-ear surgery.
abstract: OBJECTIVE
  To investigate facial nerve monitoring in patients receiving the partial nondepolarizing neuromuscular blocking agents (NMBAs), remifentanil and propofol.
  
  
  METHODS
  Patients with normal facial function and advanced middle-ear disease were enrolled. For total intravenous anaesthesia (TIVA), propofol and remifentanil were infused as induction/maintenance anaesthesia. Stimulation thresholds and amplitudes were recorded at each train-of-four (TOF) nerve stimulation level. Time differences between start of TOF and electromyographic (EMG) amplitude decreases (Ti), and between complete recovery of TOF and EMG amplitudes (Tr), were calculated.
  
  
  RESULTS
  Fifteen patients were enrolled. Mean ± SD Ti was 3.4 ± 1.28 min; Tr was 18.7 ± 4.41 min. Amplitude of stimulation was apparent mostly at TOF level 1. In most cases, no or a weak response (<100 µV) was observed at TOF 0. Mean ± SD threshold of electrical stimulation was 0.31 ± 0.10 mA at TOF 1. At TOF > 2, all cases showed EMG response on electrical stimulation.
  
  
  CONCLUSIONS
  Induction of TIVA using propofol and remifentanil provided reliable conditions for delicate microsurgery. Minimal NMBA use, considered as producing TOF levels >1, was sufficient for facial nerve monitoring in neuro-otological surgery.
authors: Department of Anaesthesiology and Pain Medicine, Inje University College of Medicine, Ilsan Paik Hospital, Gyeonggi-do, Republic of Korea.
authors: Won Joo
authors: WJ
authors: Choe
authors: Jun Hyun
authors: JH
authors: Kim
authors: Si Young
authors: SY
authors: Park
authors: Jin
authors: J
authors: Kim
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000732:Androstanols / Q000627:therapeutic use*; D018686:Anesthetics, Intravenous / Q000627:therapeutic use; D018424:Cholesteatoma, Middle Ear / Q000473:pathology / Q000601:surgery*; D004432:Ear, Middle / Q000187:drug effects / Q000473:pathology / Q000601:surgery*; D004576:Electromyography; D005154:Facial Nerve / Q000187:drug effects*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative; D019148:Neuromuscular Blockade / Q000379:methods; D003473:Neuromuscular Nondepolarizing Agents / Q000627:therapeutic use*; D013506:Otologic Surgical Procedures; D010880:Piperidines / Q000627:therapeutic use; D015742:Propofol / Q000627:therapeutic use; D000077208:Remifentanil; D000077123:Rocuronium; D004561:Transcutaneous Electric Nerve Stimulation
chemical_list: D000732:Androstanols; D018686:Anesthetics, Intravenous; D003473:Neuromuscular Nondepolarizing Agents; D010880:Piperidines; D000077208:Remifentanil; D000077123:Rocuronium; D015742:Propofol
keywords: Facial nerve; electromyography; monitoring; neuro-otological surgery; propofol; remifentanil train-of-four; total intravenous anaesthesia