title: Reducing the pain of microemulsion propofol injections: a double-blind, randomized study of three methods of tourniquet and lidocaine.
abstract: BACKGROUND
  Although the new formulation of lipid-free microemulsion propofol (MP) has some advantages over the lipid emulsion, it reportedly produces more injection pain than lipid-based propofol. Intravenous lidocaine with application of a rubber tourniquet before administration of propofol is considered to be the best method for reducing injection pain; however, this technique is not perfect.
  
  
  OBJECTIVE
  The goal of this study was to evaluate the effect of different methods of tourniquet application and lidocaine administration on MP injection pain.
  
  
  METHODS
  This single-center, randomized controlled clinical trial was conducted in 140 patients aged 18 to 65 years. Patients were randomly divided into 4 groups (n = 35 each). Group A received MP (2 mg/kg) after lidocaine (0.6 mg/kg) with a tourniquet with arm down (venous engorgement); group B received MP after lidocaine with a tourniquet with arm up (venous gravity drainage); group C received MP with a tourniquet with arm down; and group D (control group) received MP only (with no tourniquet). In groups A and C, the tourniquet was released after MP; in group B, the tourniquet was released before MP. Injection pain was evaluated by using a verbal pain score (VPS). The bispectral index, the time from the beginning of drug injection to the loss of eyelash reflex, and time to the lowest bispectral index value were recorded.
  
  
  RESULTS
  Group A showed significantly less incidence of pain than the control group when MP was injected. The mean VPS was significantly lower in groups A, B, and C than in group D (the control group). The VPS of group A was significantly lower than that in group B. Other observed values were not significantly different.
  
  
  CONCLUSIONS
  We concluded that intravenous retention of lidocaine with the application of a rubber tourniquet under venous engorgement of the arm reduces the incidence and intensity of MP injection pain.
  
  
  BACKGROUND
  UMIN000010725.
authors.affiliation: Anesthesiology and Pain Medicine, Korea University Guro Hospital, Seoul, Republic of Korea.
authors.forename: Kyungjong
authors.initials: K
authors.lastname: Kim
authors.forename: Young
authors.initials: Y
authors.lastname: Sung Kim
authors.forename: Dong-Kyu
authors.initials: DK
authors.lastname: Lee
authors.forename: Byung-Gun
authors.initials: BG
authors.lastname: Lim
authors.forename: Hee-Zoo
authors.initials: HZ
authors.lastname: Kim
authors.forename: Myoung-Hoon
authors.initials: MH
authors.lastname: Kong
authors.forename: Nan-Suk
authors.initials: NS
authors.lastname: Kim
authors.forename: Il-Ok
authors.initials: IO
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D018686:Anesthetics, Intravenous / Q000008:administration & dosage*; D000779:Anesthetics, Local / Q000008:administration & dosage*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D006940:Hyperemia; D007275:Injections, Intravenous / Q000379:methods*; D008012:Lidocaine / Q000008:administration & dosage*; D008297:Male; D008875:Middle Aged; D010146:Pain / Q000188:drug therapy* / Q000209:etiology*; D015742:Propofol / Q000008:administration & dosage*; D014111:Tourniquets; D055815:Young Adult
chemical_list: D018686:Anesthetics, Intravenous; D000779:Anesthetics, Local; D008012:Lidocaine; D015742:Propofol
keywords: injection pain; lidocaine; microemulsion propofol; tourniquet