title: [Haemodynamic effects of intoxication with bupivacaine and enantiomeric excess mixture. Experimental study in swine].
abstract: BACKGROUND
  Racemic bupivacaine has been the local anaesthetic of choice in regional blocks due to quality and duration of anesthesia. However its cardiovascular toxicity has been a source of concern and research has been made for lesser impact drugs. One choice is its levogyre isomer, levobupivacaine, apparently less cardiotoxic due a lower affinity to the heart sodium channels. In Brazil, a drug containing 75% of levogyre isomer and 25% of dextrogyre isomer, called enantiomeric excess mixture, is available. This study intends to evaluate haemodynamic effects of the intravascular injection of a toxic dose of both agents in swine.
  
  
  METHODS
  Large White pigs were anaesthetized with thiopental, intubated and placed on mechanical ventilation. Haemodynamic monitoring was performed with an invasive blood pressure and Swan-Ganz catheter on a pulmonary artery. After a 30 minute rest period, animals were randomly divided in two groups and the intoxication was performed on a double-blind method with 4 mg.kg-1 of one of the drugs. Haemodynamic parameters were then evaluated at 1, 5, 10, 15, 20 and 30 minutes.
  
  
  RESULTS
  The enantiomeric excess mixture caused greater haemodynamic effects than the racemic bupivacaine. These results diverge from those found in humans with levogyre isomer but are similar to recent results reported in animals. Care should be taken when extrapolating data obtained in swine to humans and further research is necessary.
  
  
  CONCLUSIONS
  When high doses are injected in swine, the enantiomeric excess mixture was more toxic than the racemic bupivacaine.
authors.affiliation: Laboratório de Anestesia Experimental, Núcleo de Medicina e Cirurgia Experimental, FCM, UNICAMP, Campinas, SP. audelsmann@yahoo.com.br
authors.forename: Artur
authors.initials: A
authors.lastname: Udelsmann
authors.forename: Sílvia Elaine Rodolfo de Sá
authors.initials: SE
authors.lastname: Lorena
authors.forename: Samira Ubaid
authors.initials: SU
authors.lastname: Girioli
authors.forename: William Adalberto
authors.initials: WA
authors.lastname: Silva
authors.forename: Ana Cristina de
authors.initials: AC
authors.lastname: Moraes
mesh_terms: D000771:Anesthesia, Intravenous; D000779:Anesthetics, Local / Q000737:chemistry / Q000633:toxicity*; D000818:Animals; D002045:Bupivacaine / Q000737:chemistry / Q000633:toxicity*; D002319:Cardiovascular System / Q000187:drug effects*; D004195:Disease Models, Animal; D004353:Drug Evaluation, Preclinical; D005260:Female; D006439:Hemodynamics / Q000187:drug effects*; D008297:Male; D013237:Stereoisomerism; D013552:Swine
chemical_list: D000779:Anesthetics, Local; D002045:Bupivacaine
vernacular_title: Efeitos hemodinâmicos da intoxicação aguda com bupivacaína e a mistura enantiomérica--estudo experimental em suínos.