title: Lipid emulsion pretreatment has different effects on mepivacaine and bupivacaine cardiac toxicity in an isolated rat heart model.
abstract: BACKGROUND
  The use of lipid emulsions to reduce cardiac toxicity of local anaesthetics (LAs) has shown success in experimental studies and some clinical cases, and thus has been implemented in clinical practice. However, lipid treatment is usually given after the occurrence of neurological or cardiovascular symptoms of systemic intoxication. The aim of this study was to determine if pretreatment with lipid emulsion reduces cardiac toxicity produced by bupivacaine or mepivacaine.
  
  
  METHODS
  Isolated rat hearts were perfused with or without lipid emulsion (0.25 ml kg(-1) min(-1)) before administration of equipotent doses of bupivacaine (250 µM) or mepivacaine (1000 µM). Haemodynamic parameters and times from start of perfusion LA to a 1 min period of asystole and recovery were determined.
  
  
  RESULTS
  Pretreatment with lipid emulsion extended the time until occurrence of asystole and decreased times to recovery in bupivacaine-induced cardiac toxicity but not in mepivacaine-induced cardiac toxicity compared with control. Lipid pretreatment impaired rate-pressure product recovery in mepivacaine-intoxicated hearts.
  
  
  CONCLUSIONS
  This study confirms that pretreatment with a lipid emulsion reduces cardiac toxicity of LAs. The efficacy of pretreatment with lipid emulsion was LA-dependent, so pharmacokinetic properties, such as lipophilicity, might influence the effects of lipid emulsion pretreatment.
authors.affiliation: Department of Anaesthesiology, University of Regensburg, Regensburg, Germany.
authors.forename: C
authors.initials: C
authors.lastname: Aumeier
authors.forename: B
authors.initials: B
authors.lastname: Kasdorf
authors.forename: M
authors.initials: M
authors.lastname: Gruber
authors.forename: H
authors.initials: H
authors.lastname: Busse
authors.forename: C H
authors.initials: CH
authors.lastname: Wiese
authors.forename: W
authors.initials: W
authors.lastname: Zink
authors.forename: B M
authors.initials: BM
authors.lastname: Graf
authors.forename: Y A
authors.initials: YA
authors.lastname: Zausig
mesh_terms: D000779:Anesthetics, Local / Q000633:toxicity*; D000818:Animals; D002045:Bupivacaine / Q000633:toxicity*; D004334:Drug Administration Schedule; D005217:Fat Emulsions, Intravenous / Q000008:administration & dosage / Q000494:pharmacology*; D006321:Heart / Q000187:drug effects*; D006323:Heart Arrest / Q000139:chemically induced / Q000503:physiopathology / Q000517:prevention & control*; D006339:Heart Rate / Q000187:drug effects; D008619:Mepivacaine / Q000633:toxicity*; D009924:Organ Culture Techniques; D051381:Rats; D017208:Rats, Wistar; D016277:Ventricular Function, Left / Q000187:drug effects
chemical_list: D000779:Anesthetics, Local; D005217:Fat Emulsions, Intravenous; D008619:Mepivacaine; D002045:Bupivacaine
keywords: bupivacaine; cardiac arrest; fat emulsion; heart; mepivacaine