title: Influence of nondepolarizing muscle relaxants on intraoperative neuromonitoring during thyroid surgery.
abstract: OBJECTIVE
  The objective of this study was to find a nondepolarizing muscle relaxant to replace succinylcholine during thyroid surgery with intraoperative neuromonitoring (IONM) because succinylcholine can cause severe adverse effects.
  
  
  METHODS
  Prospective study of 232 patients undergoing thyroidectomies.
  
  
  METHODS
  A tertiary medical centre.
  
  
  METHODS
  One hundred thirty-one patients received 0.5 mg/kg rocuronium (group R) and 101 patients received 0.5 mg/kg atracurium (group A) to facilitate electromyographic (EMG) endotracheal tube insertion. EMG signals were obtained from the vagus nerve before and after dissection of the recurrent laryngeal nerve and were defined as the V1 and the V2 signal, respectively. Accelerometry (twitch [% TW]) was used to monitor the quantitative degree of neuromuscular transmission at the adductor pollicis muscle.
  
  
  METHODS
  The amplitude (muV) of the V1 and V2 signals and the correlated degree of neuromuscular transmission (% TW).
  
  
  RESULTS
  V1 and V2 signals were obtained from all patients successfully. The % TW at the V1 signal was significantly lower than that at the V2 signal in group R and group A. The mean recovery time from complete neuromuscular blockade to the initial twitch was 43.9 +/- 11 minutes. Only in the subgroup in which the correlated TW was 0% while eliciting the V1 signal were the amplitudes of the V1 signals significantly lower than those of the V2 signal in both groups.
  
  
  CONCLUSIONS
  A single dose (0.5 mg/kg) of rocuronium and atracurium was feasible for IONM during thyroid surgery. This study showed that 44 minutes after administration of these two muscle relaxants is adequate for eliciting an EMG signal from the vagus nerve.
authors.affiliation: Department of Anesthesiology, Kaohsiung Medical University Hospital, Kaohsiung, Taiwan.
authors.forename: Koung-Shing
authors.initials: KS
authors.lastname: Chu
authors.forename: Cheng-Jing
authors.initials: CJ
authors.lastname: Tsai
authors.forename: I-Cheng
authors.initials: IC
authors.lastname: Lu
authors.forename: Kuang-Yi
authors.initials: KY
authors.lastname: Tseng
authors.forename: Siu-Wah
authors.initials: SW
authors.lastname: Chau
authors.forename: Che-Wei
authors.initials: CW
authors.lastname: Wu
authors.forename: Ka-Wo
authors.initials: KW
authors.lastname: Lee
authors.forename: Wen-Rei
authors.initials: WR
authors.lastname: Kuo
authors.forename: Feng-Yu
authors.initials: FY
authors.lastname: Chiang
mesh_terms: D000328:Adult; D000368:Aged; D000732:Androstanols / Q000008:administration & dosage; D000768:Anesthesia, General / Q000379:methods*; D001279:Atracurium / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D004576:Electromyography / Q000187:drug effects; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D016343:Monitoring, Intraoperative / Q000379:methods*; D009469:Neuromuscular Junction / Q000187:drug effects; D003473:Neuromuscular Nondepolarizing Agents / Q000008:administration & dosage*; D011446:Prospective Studies; D000077123:Rocuronium; D013965:Thyroidectomy / Q000379:methods*; D016896:Treatment Outcome; D014826:Vocal Cord Paralysis / Q000517:prevention & control; D055815:Young Adult
chemical_list: D000732:Androstanols; D003473:Neuromuscular Nondepolarizing Agents; D001279:Atracurium; D000077123:Rocuronium