title: The volume effect of lidocaine on thoracic epidural anesthesia in conscious Beagle dogs.
abstract: OBJECTIVE
  To evaluate the volume effect of local anesthetic solution on thoracic epidural analgesia in dogs.
  
  
  METHODS
  Prospective, experimental trial.
  
  
  METHODS
  Five healthy adult Beagle dogs weighing 9.7 ± 1.3 kg.
  
  
  METHODS
  A catheter was inserted into the seventh thoracic epidural space using a lumbosacral approach, and secured with suture under total intravenous (IV) anesthesia with propofol. Each dog was administered four volume treatments (0.05, 0.10, 0.15 and 0.20 mL kg(-1)) of 2% lidocaine via the catheter at 12 hour intervals. In every treatment, dogs were re-anesthetized with propofol (6 mg kg(-1), IV) and isoflurane, and received iohexol at each volume to visualize the epidural distribution (ED) through computed tomography. Three hours after epidurography, when dogs had recovered from anesthesia, the appropriate volume of lidocaine was injected through the catheter, and sensory blockade (SB) in dermatomes was evaluated by pinching with a mosquito forceps. Results were presented as median (range), and the volume effect on ED and SB was analyzed with one-way Kruskal-Wallis anova.
  
  
  RESULTS
  In proportion to volumes (0.05, 0.10, 0.15 and 0.20 mL kg(-1)), there were significant increases in the extent of ED from 7.4 (5.5-9.0) to 10.4 (8.0-12.0), 13.2 (12.5-13.0), and 15.2 (13.0-18.0) vertebrae, respectively, p < 0.001, and in SB from 2.7 (1.0-5.0) to 6.8 (4.5-10.5), 9.9 (6.5-13.0), and 13.1 (11.0-15.0) dermatomes, respectively, p < 0.001. Unilateral ED and SB were observed in all treatments with various grades, and this distribution was more frequent in the low volume treatments. In the high volume treatments, temporary complications including Horner's syndrome, ataxia, paraplegia, depression, stupor, and intermittent cough occurred often.
  
  
  CONCLUSIONS
  The increase in volume of local anesthetic solution improved SB by resulting in more consistent bilateral dermatome blockade as well as an extended blockade. However, caution should be exerted, as higher volume injections of lidocaine caused side effects in all dogs.
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Seoul National University, Seoul, South Korea.
authors.forename: Won-gyun
authors.initials: WG
authors.lastname: Son
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Seoul National University, Seoul, South Korea.
authors.forename: Min
authors.initials: M
authors.lastname: Jang
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Seoul National University, Seoul, South Korea.
authors.forename: Sang-min
authors.initials: SM
authors.lastname: Jo
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Seoul National University, Seoul, South Korea.
authors.forename: Junghee
authors.initials: J
authors.lastname: Yoon
authors.affiliation: Department of Veterinary Clinical Sciences, College of Veterinary Medicine, Seoul National University, Seoul, South Korea.
authors.forename: Inhyung
authors.initials: I
authors.lastname: Lee
mesh_terms: D000767:Anesthesia, Epidural / Q000662:veterinary*; D000779:Anesthetics, Local / Q000008:administration & dosage*; D000818:Animals; D004285:Dogs / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D007268:Injections, Epidural / Q000662:veterinary; D008012:Lidocaine / Q000008:administration & dosage*; D008297:Male; D011446:Prospective Studies; D013904:Thoracic Vertebrae
chemical_list: D000779:Anesthetics, Local; D008012:Lidocaine
keywords: dog; lidocaine; neurologic effects; thoracic epidural; volume