title: Effects of ethyl chloride spray on pain and parameters of needle electromyography in the upper extremity.
abstract: OBJECTIVE
  The aim of this study was to compare the effects of ethyl chloride and placebo sprays for reducing pain induced by needle electromyography and changes in parameters of the motor unit action potential during needle electromyography of the upper extremity.
  
  
  METHODS
  Sixty patients were randomized into the ethyl chloride or placebo spray groups. In both groups, spray was applied just before needle electromyography of the flexor carpi radialis, and a visual analog scale to evaluate the pain of needle electromyography and a five-point Likert scale for patient satisfaction and preference for reexamination were compared between the two groups. Then, changes in the amplitude, phases, turns, and duration of the motor unit action potential during needle electromyography of the biceps brachii were compared before and after spraying in each group.
  
  
  RESULTS
  The visual analog scale was significantly lower, and patient satisfaction and preference for reexamination were significantly higher in the ethyl chloride spray group. Among the parameters of the motor unit action potential, there were no significant changes except for an increased duration after spraying with ethyl chloride.
  
  
  CONCLUSIONS
  Ethyl chloride spray can effectively reduce pain, but it must be used with caution because it may affect parameters of the motor unit action potential during needle electromyography.
authors.affiliation: From the Department of Anesthesiology and Pain Medicine, Catholic University, Seoul St. Mary's Hospital, Seoul (Y-EM); and Department of Physical Medicine and Rehabilitation, College of Medicine, Soonchunhyang University, Bucheon, Republic of Korea (S-HK).
authors.forename: Young-Eun
authors.initials: YE
authors.lastname: Moon
authors.forename: Sang-Hyun
authors.initials: SH
authors.lastname: Kim
mesh_terms: D000328:Adult; D000772:Anesthesia, Local / Q000379:methods*; D000779:Anesthetics, Local / Q000008:administration & dosage; D004576:Electromyography / Q000009:adverse effects* / Q000295:instrumentation; D005018:Ethyl Chloride / Q000008:administration & dosage*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009339:Needles / Q000009:adverse effects*; D010146:Pain / Q000209:etiology / Q000517:prevention & control*; D010147:Pain Measurement; D017060:Patient Satisfaction / Q000706:statistics & numerical data; D034941:Upper Extremity
chemical_list: D000779:Anesthetics, Local; D005018:Ethyl Chloride