title: A combination of lidocaine and nitrous oxide in oxygen is more effective in preventing pain on propofol injection than either treatment alone.
abstract: OBJECTIVE
  Propofol is an intravenous (i.v.) anaesthetic agent that possesses many of the qualities of an ideal anaesthetic agent. The most significant side-effect associated with propofol is pain on injection. Despite optimal therapy, the incidence of pain on propofol injection remains a problem. This prospective, randomized, double blinded study evaluated the effect of three different treatment strategies in decreasing pain on propofol injection.
  
  
  METHODS
  We studied 102 adult, ASA I-II patients, scheduled for elective surgical procedures. Combination of i.v. lidocaine and nitrous oxide (N2O) in oxygen (O2) inhalation pre-treatment was compared with either treatment alone in the prevention of pain on propofol injection. A standard propofol injection technique and scoring system, to measure the pain on injection was used.
  
  
  RESULTS
  Demographic variables were similar between the groups. The incidence of no pain on propofol injection was similar in the lidocaine and N2O groups (63.6% vs. 57.5%) (95% confidence interval (CI): 0.17-0.29, P = 0.61). Combination therapy was associated with a greater incidence of no pain on injection (84% vs. 63.6%) (95% CI: 0.06-0.48, P = 0.04).
  
  
  CONCLUSIONS
  Combination of i.v. lidocaine and N2O in O2 inhalation pre-treatment is more effective than either treatment alone in decreasing pain on propofol injection.
authors.affiliation: Beaumont Hospital, Department of Anaesthesia and Intensive Care Medicine, Dublin, Ireland. ahtshamniazi@hotmail.com
authors.forename: A
authors.initials: A
authors.lastname: Niazi
authors.forename: E
authors.initials: E
authors.lastname: Galvin
authors.forename: I
authors.initials: I
authors.lastname: Elsaigh
authors.forename: Z
authors.initials: Z
authors.lastname: Wahid
authors.forename: D
authors.initials: D
authors.lastname: Harmon
authors.forename: I
authors.initials: I
authors.lastname: Leonard
mesh_terms: D000293:Adolescent; D000328:Adult; D018685:Anesthetics, Inhalation / Q000627:therapeutic use*; D018686:Anesthetics, Intravenous / Q000008:administration & dosage / Q000009:adverse effects*; D000779:Anesthetics, Local / Q000627:therapeutic use*; D004311:Double-Blind Method; D004359:Drug Therapy, Combination; D005260:Female; D006801:Humans; D008012:Lidocaine / Q000627:therapeutic use*; D008297:Male; D011939:Mental Recall; D008875:Middle Aged; D009609:Nitrous Oxide / Q000627:therapeutic use*; D010100:Oxygen / Q000494:pharmacology; D010146:Pain / Q000517:prevention & control* / Q000523:psychology; D010147:Pain Measurement / Q000187:drug effects; D015742:Propofol / Q000008:administration & dosage / Q000009:adverse effects*; D011446:Prospective Studies
chemical_list: D018685:Anesthetics, Inhalation; D018686:Anesthetics, Intravenous; D000779:Anesthetics, Local; D008012:Lidocaine; D009609:Nitrous Oxide; D010100:Oxygen; D015742:Propofol