title: Ultrasound-assisted periconal ocular blockade in rabbits.
abstract: OBJECTIVE
  This study aimed to evaluate the benefit and specifically the feasibility of using ultrasound in ophthalmologic periconal block, and the occurrence of complications.
  
  
  METHODS
  Prospective experimental study.
  
  
  METHODS
  Ten healthy New Zealand White rabbits (6-8 months of age), weighing 2.0-3.5 kg.
  
  
  METHODS
  Rabbits were anesthetized by intramuscular injection of acepromazine (1 mg kg(-1)), ketamine (30 mg kg(-1)) and xylazine (3 mg kg(-1)). Ultrasound-assisted periconal block with lidocaine was performed on 18 eyes. Intraocular pressure was measured by applanation tonometry whereas corneal sensitivity was assessed using an esthesiometer, before and after each periconal anesthesia.
  
  
  RESULTS
  In all 18 eyes, it was possible to adequately visualize the needle shaft within the periconal space, as well as muscular cone, optic nerve and local anesthetic solution spread. Lidocaine 2% without epinephrine (0.79 ± 0.19 mL) was injected into the periconal space. There was no statistical difference between the intraocular pressure (mean ± SD) measured before (10.9 ± 2.9 mmHg) and after (11.9 ± 3.8 mmHg) the periconal anesthesia (p = 0.38). The effectiveness of the ultrasound-assisted technique was shown according to the values for corneal sensitivity, assessed before and after periconal anesthesia (p < 0.0001). Complications were not observed in this study.
  
  
  CONCLUSIONS
  Eye ultrasonography allowed visualization of all anatomic structures necessary to perform a periconal block, as well as the needle insertion and anesthetic spread in real time. Further studies are required to prove the real potential of ultrasound for reducing the incidence of complications associated with ophthalmic blocks, especially when anatomic disorders of the eye could potentially increase the risk.
  
  
  CONCLUSIONS
  Ultrasonography is a painless, noninvasive tool that may improve safety of ophthalmic regional blocks, potentially by reducing the prevalence of globe perforation or penetration of the optic nerve associated with the needle-based techniques.
authors.affiliation: Department of Anesthesiology, Botucatu School of Medicine, UNESP - Universidade Estadual Paulista, Botucatu, SP, Brazil.
authors.forename: Ilana E
authors.initials: IE
authors.lastname: Najman
authors.affiliation: Department of Animal Science, Araçatuba Veterinary School, UNESP - Universidade Estadual Paulista, Araçatuba, SP, Brazil.
authors.forename: Joana Z
authors.identifier: http://orcid.org/0000-0003-0861-371X
authors.initials: JZ
authors.lastname: Ferreira
authors.affiliation: Department of Anesthesiology, Botucatu School of Medicine, UNESP - Universidade Estadual Paulista, Botucatu, SP, Brazil.
authors.forename: Caio J X
authors.initials: CJ
authors.lastname: Abimussi
authors.affiliation: Department of Animal Science, Araçatuba Veterinary School, UNESP - Universidade Estadual Paulista, Araçatuba, SP, Brazil.
authors.forename: Beatriz P
authors.initials: BP
authors.lastname: Floriano
authors.affiliation: Department of Animal Science, Araçatuba Veterinary School, UNESP - Universidade Estadual Paulista, Araçatuba, SP, Brazil.
authors.forename: Thais M
authors.initials: TM
authors.lastname: Meneghetti
authors.affiliation: Department of Clinical, Surgery and Animal Reproduction, Araçatuba Veterinary School, UNESP - Universidade Estadual Paulista, Araçatuba, SP, Brazil.
authors.forename: Valéria N L S
authors.initials: VN
authors.lastname: Oliva
authors.affiliation: Department of Anesthesiology, Botucatu School of Medicine, UNESP - Universidade Estadual Paulista, Botucatu, SP, Brazil.
authors.forename: Paulo
authors.initials: P
authors.lastname: do Nascimento
mesh_terms: D000758:Anesthesia / Q000662:veterinary; D000779:Anesthetics, Local / Q000008:administration & dosage*; D000818:Animals; D005123:Eye / Q000000981:diagnostic imaging / Q000294:innervation*; D056965:Injections, Intraocular / Q000662:veterinary; D008012:Lidocaine / Q000008:administration & dosage*; D009407:Nerve Block / Q000662:veterinary*; D009801:Oculomotor Muscles / Q000294:innervation; D009884:Ophthalmodynamometry / Q000662:veterinary; D011446:Prospective Studies; D011817:Rabbits; D018084:Ultrasonography, Interventional / Q000662:veterinary*
chemical_list: D000779:Anesthetics, Local; D008012:Lidocaine
keywords: anesthesia; eye; periconal blockade; rabbits; ultrasound