title: Cardiovascular tolerance of intravenous lidocaine in broiler chickens (Gallus gallus domesticus) anesthetized with isoflurane.
abstract: OBJECTIVE
  To determine the cardiovascular effects of lidocaine infused intravenously (IV) in broiler chickens.
  
  
  METHODS
  Two phase study: Phase 1, randomized up-and-down study to determine effective dose 50 (ED50) for lidocaine; Phase 2, prospective randomized study to determine the cardiovascular effects of lidocaine.
  
  
  METHODS
  Seventeen Ross-708 broiler chickens (Gallus gallus domesticus) [11 chickens (Phase 1) and 6 chickens (Phase 2)], weighing 2.6-4.3 kg.
  
  
  METHODS
  After induction of anesthesia with isoflurane and placement of monitoring equipment including invasive blood pressure, chickens were administered lidocaine IV. During Phase 1, using an up-and-down design, each animal received a variable dose selected based on the response of the previous animal. During Phase 2, each animal was administered 6 mg kg(-1) of lidocaine IV over 2 minutes. Clinically irrelevant cardiovascular effects were defined as a relative decrease of heart rate (HR) and mean blood pressure (MAP) <30% subsequent to IV lidocaine administration. The ED50 was defined as the dose rate that would cause clinically irrelevant cardiovascular depression in 50% of the population.
  
  
  RESULTS
  During Phase 1, using an up-and-down study design (n = 11), the ED50 of lidocaine was determined to be 6.30 mg kg(-1) and 6.22 mg kg(-1) (95% confidence interval, 5.30-7.13 mg kg(-1)), when calculated by Dixon's up-and-down method, and logistic regression, respectively. During Phase 2, following infusion of lidocaine (6 mg kg(-1)), no clinically relevant effects on HR or MAP were detected in any animal.
  
  
  CONCLUSIONS
  Previous reports state that the dose of lidocaine used in birds should be ≤4 mg kg(-1). In this study, 6 mg kg(-1) of lidocaine injected IV was not associated with adverse cardiovascular effects. These results suggest that the dose of 4 mg kg(-1) can be exceeded, at least in chickens, and opens the possibility of other therapeutic uses for lidocaine in birds.
authors.affiliation: Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA.
authors.forename: João
authors.initials: J
authors.lastname: Brandão
authors.affiliation: Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA.
authors.forename: Anderson F
authors.initials: AF
authors.lastname: da Cunha
authors.affiliation: Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA, USA.
authors.forename: Bruno
authors.initials: B
authors.lastname: Pypendop
authors.affiliation: Department of Laboratory Animal Medicine, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA.
authors.forename: Rhett
authors.initials: R
authors.lastname: Stout
authors.affiliation: Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA.
authors.forename: Javier
authors.initials: J
authors.lastname: Nevarez
authors.affiliation: Department of Veterinary Clinical Sciences, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA, USA.
authors.forename: Thomas N
authors.initials: TN
authors.lastname: Tully
mesh_terms: D000769:Anesthesia, Inhalation / Q000662:veterinary; D018685:Anesthetics, Inhalation / Q000008:administration & dosage; D000779:Anesthetics, Local / Q000008:administration & dosage*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002645:Chickens / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D006339:Heart Rate / Q000187:drug effects; D007262:Infusions, Intravenous / Q000662:veterinary; D007530:Isoflurane / Q000008:administration & dosage; D008012:Lidocaine / Q000008:administration & dosage*
chemical_list: D018685:Anesthetics, Inhalation; D000779:Anesthetics, Local; D008012:Lidocaine; D007530:Isoflurane
keywords: Ross-708; avian; bird; lidocaine; local anesthesia; toxicity