title: Response to rocuronium and its determinants in patients with myasthenia gravis: A case-control study.
abstract: BACKGROUND
  Several previous studies using univariate analysis have suggested that the pre-anaesthetic train-of-four (TOF) ratio, concentration of anti-acetylcholine receptor (AChR) antibodies and the presence of preoperative generalised muscular involvement are determinants of an increased response to neuromuscular blocking agents (NMBAs) in patients with myasthenia gravis. However, the determinants of the response of patients with myasthenia gravis to rocuronium, which is expected to be used more frequently since the advent of sugammadex, have not been studied.
  
  
  OBJECTIVE
  To clarify whether previously suggested determinants of the response to other intermediate-acting NMBAs would also affect the response to rocuronium and to reveal the determinants of the increased response to rocuronium in individual patients with myasthenia gravis using multivariate analysis.
  
  
  METHODS
  Case control study.
  
  
  METHODS
  Kumamoto University Hospital, November 2010 to September 2013.
  
  
  METHODS
  Thirty-eight patients with myasthenia gravis having surgery using a total intravenous anaesthetic technique were investigated. After induction of general anaesthesia, the 95% effective dose (ED95) of rocuronium was calculated using cumulative dose-finding methods. Neuromuscular function was monitored by acceleromyographic assessment of TOF responses of the adductor pollicis muscle to ulnar nerve stimulation. Patients were then divided into the increased response (ED95 <0.15 mg kg, n = 13) and non-increased response groups (ED95 ≥0.15 mg kg, n = 25).
  
  
  METHODS
  Demographic data, TOF ratio before rocuronium injection (baseline TOF ratio), concentration of anti-AChR antibodies, Osserman classification and treatment for myasthenia gravis in the two groups were compared.
  
  
  RESULTS
  Stepwise logistic regression identified baseline TOF ratio and age of onset of myasthenia gravis as determinants of the increased response to rocuronium in patients with myasthenia gravis [odds ratios (95% confidence interval) of 0.87 (0.77 to 0.98; P = 0.02) and 0.92 (0.86 to 0.99; P = 0.03), respectively].
  
  
  CONCLUSIONS
  Multivariate analysis identified baseline TOF ratio and age of disease onset as determinants of the increased response to rocuronium in patients with myasthenia gravis.
  
  
  BACKGROUND
  Registered with UMIN Clinical Trials Registry, identifier: UMIN000006766.
authors.affiliation: From the Department of Anesthesiology, Graduate School of Medical Sciences, Kumamoto University Hospital, Kumamoto-City, Kumamoto, Japan.
authors.forename: Masafumi
authors.initials: M
authors.lastname: Fujimoto
authors.forename: Shuhei
authors.initials: S
authors.lastname: Terasaki
authors.forename: Masaaki
authors.initials: M
authors.lastname: Nishi
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Yamamoto
mesh_terms: D061725:Accelerometry; D000328:Adult; D000368:Aged; D000732:Androstanols / Q000008:administration & dosage*; D000768:Anesthesia, General / Q000379:methods; D016022:Case-Control Studies; D005260:Female; D006785:Hospitals, University; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D009157:Myasthenia Gravis / Q000503:physiopathology / Q000601:surgery*; D061886:Neuromuscular Monitoring; D003473:Neuromuscular Nondepolarizing Agents / Q000008:administration & dosage*; D000077123:Rocuronium; D055815:Young Adult
chemical_list: D000732:Androstanols; D003473:Neuromuscular Nondepolarizing Agents; D000077123:Rocuronium