title: Lipid composition and lidocaine effect on immediate and delayed injection pain following propofol administration.
abstract: BACKGROUND
  Propofol has been used for the induction and maintenance of anesthesia. However, patients experience vascular pain during its injection.
  
  
  OBJECTIVE
  The objective of this study was to compare the effect of the lipid type used in propofol preparations and that of lidocaine on the immediate and delayed vascular pain induced by propofol administration.
  
  
  METHODS
  In this double-blinded clinical study, 150 patients at American Society of Anesthesiologists level I-II were randomly divided into three equally sized groups. A propofol with medium and long-chain triglycerides (propofol-MCT/LCT) was administered to the first group. The second group received propofol containing propofol-LCT, and the third group received propofol-LCT and pretreatment lidocaine 20 mg. The incidence and the intensity of immediate (during injection) and delayed injection pain (after 20 s) were evaluated on a verbal analog scale (1-10) until patients' unconsciousness.
  
  
  METHODS
  Sample size was calculated with SigmaPlot version 12.5 software. Data were analyzed with Statistical Package for the Social Sciences (SPSS) version 16, one-way analysis of variance, and post-hoc Tukey. P < 0.05 was considered statistically significant.
  
  
  RESULTS
  The demographic parameters of the three groups were similar. The lidocaine group experienced the least immediate vascular pain. The intensity of pain was highest in the propofol-LCT group (P = 0.04). Additionally, the intensity of delayed pain was lowest in the propofol-MCT/LCT group (P = 0.01). The incidence of pain associated with the propofol administration was 26.5, 44, and 18%, respectively, in propofol-MCT/LCT, propofol-LCT, and lidocaine and propofol-LCT groups.
  
  
  CONCLUSIONS
  The results indicate an effect of the lipid type on delayed pain reduction, especially propofol-MCT/LCT. On the other hand, the lidocaine decreases immediate propofol-LCT vascular pain.
authors.affiliation: Cardiac Anesthesia Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Nahid
authors.initials: N
authors.lastname: Zirak
authors.affiliation: Cardiac Anesthesia Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Alireza
authors.initials: A
authors.lastname: Bameshki
authors.affiliation: Cardiac Anesthesia Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Mohammadjavad
authors.initials: M
authors.lastname: Yazdani
authors.affiliation: Cardiac Anesthesia Research Center, School of Medicine, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Mehryar Taghavi
authors.initials: MT
authors.lastname: Gilani
keywords: Lidocaine; pain; propofol