title: Preventing pain during injection of propofol: effects of a new emulsion with lidocaine addition.
abstract: OBJECTIVE
  Previous studies found that lidocaine addition to propofol long-chain triglyceride was associated with a lower incidence of injection pain than medium-chain triglyceride/long-chain triglyceride formulation, but the incidence was still high (31-40%). Our study investigated whether the incidence of injection pain could be further reduced by the addition of lidocaine (10 mg, 20:1) to propofol medium-chain triglyceride/long-chain triglyceride.
  
  
  METHODS
  In a randomized double-blind controlled trial 464 patients scheduled to undergo regional anaesthesia were assigned to receive one of the following four options: propofol medium-chain triglyceride/long-chain triglyceride + lidocaine, propofol long-chain triglyceride + lidocaine, propofol medium-chain triglyceride/long-chain triglyceride or propofol long-chain triglyceride. Propofol was injected to reach grade 3 of the Observer's Assessment of Alertness/Sedation scale.
  
  
  RESULTS
  Incidence of injection pain was 18% in the propofol medium-chain triglyceride/long-chain triglyceride + lidocaine group, 31% in the propofol long-chain triglyceride + lidocaine group, 47% in the propofol medium-chain triglyceride/long-chain triglyceride group and 60% in the long-chain triglyceride group. Propofol medium-chain triglyceride/long-chain triglyceride + lidocaine was associated with a statistically significant reduced incidence of injection pain compared with propofol long-chain triglyceride +lidocaine (P =0.0249, number needed to treat =7.7).
  
  
  CONCLUSIONS
  Premixing propofol medium-chain triglyceride/long-chain triglyceride with lidocaine is one of the most effective measures currently available to reduce the incidence of injection pain in sedated patients during regional anaesthesia.
authors.affiliation: Klinikum Minden, Department of Anaesthesiology, Minden, Germany. b.bachmann-m@klinikum-minden.de
authors.forename: B
authors.initials: B
authors.lastname: Bachmann-Mennenga
authors.forename: A
authors.initials: A
authors.lastname: Ohlmer
authors.forename: R Hasso
authors.initials: RH
authors.lastname: Boedeker
authors.forename: M
authors.initials: M
authors.lastname: Mann
authors.forename: B
authors.initials: B
authors.lastname: Mühlenbruch
authors.forename: M
authors.initials: M
authors.lastname: Heesen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004655:Emulsions; D005260:Female; D006801:Humans; D007267:Injections; D008012:Lidocaine / Q000008:administration & dosage / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000145:classification / Q000517:prevention & control*; D015742:Propofol / Q000008:administration & dosage / Q000494:pharmacology*; D011795:Surveys and Questionnaires
chemical_list: D004655:Emulsions; D008012:Lidocaine; D015742:Propofol