title: Radial artery cannulation: topical amethocaine gel versus lidocaine infiltration.
abstract: BACKGROUND
  In a prospective randomized study, we compared topical 4% amethocaine gel (Ametop) with 2% lidocaine infiltration for analgesia for radial artery cannulation. A previous study had shown topical analgesia with EMLA cream reduced pain, shortened cannulation time, and improved success rates when compared with lidocaine infiltration.
  
  
  METHODS
  One hundred adult patients undergoing elective cardiac surgery were randomized. Cannulation times and success rates were compared between the two groups. The quality of analgesia was assessed using a visual analogue scale (VAS) and four-point verbal pain scoring system.
  
  
  RESULTS
  Ninety-nine sets of data were analysed using Mann-Whitney U and chi-squared tests. Mean time to cannulation was 56 s in the amethocaine group (interquartile range (IQR) 41-142) and 59 s in the lidocaine group (IQR 40-105). The median pain score on the VAS was 2 in both groups (IQR 1-3.5 for amethocaine and 0-4 for lidocaine).
  
  
  CONCLUSIONS
  There was no significant difference between these two methods of analgesia for any measured variable.
authors.affiliation: Department of Anaesthesia, Royal Infirmary of Edinburgh, UK.
authors.forename: S J
authors.initials: SJ
authors.lastname: Olday
authors.forename: R
authors.initials: R
authors.lastname: Walpole
authors.forename: J Y Y
authors.initials: JY
authors.lastname: Wang
mesh_terms: D000328:Adult; D000698:Analgesia / Q000379:methods; D000779:Anesthetics, Local; D002406:Catheterization, Peripheral / Q000379:methods*; D005260:Female; D005782:Gels; D006801:Humans; D008012:Lidocaine; D008297:Male; D010147:Pain Measurement; D011446:Prospective Studies; D017534:Radial Artery; D013748:Tetracaine; D013903:Thoracic Surgery
chemical_list: D000779:Anesthetics, Local; D005782:Gels; D013748:Tetracaine; D008012:Lidocaine