• JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
  • JoomlaWorks Simple Image Rotator
 
  Bookmark and Share
 
 
Master's Dissertation
DOI
https://doi.org/10.11606/D.10.2016.tde-19092016-155909
Document
Author
Full name
Marina Cayetano Evangelista
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2016
Supervisor
Committee
Fantoni, Denise Tabacchi (President)
Aguiar, Antonio José de Araújo
Hamaji, Adilson
Title in Portuguese
Bloqueio dos nervos ciático e femoral em gatos: avaliação da dispersão da bupivacaína sob ressonância nuclear magnética e avaliação dos efeitos antinociceptivos
Keywords in Portuguese
Analgesia
Anestesia local
Bloqueio nervoso
Gatos
Abstract in Portuguese
Os bloqueios perineurais são práticos, efetivos e amplamente utilizados para o manejo da dor perioperatória, porém os estudos em gatos são escassos. O objetivo do estudo era avaliar a dispersão da bupivacaína por meio do emprego da ressonância magnética (RM) em relação aos nervos ciático (NC) e femoral (NF) e avaliar a exequibilidade, eficácia e duração dos bloqueios dos mesmos, realizados com a bupivacaína isolada ou em associação com dexmedetomidina ou buprenorfina. Na primeira fase do estudo seis gatos adultos foram submetidos ao exame de RM sob anestesia geral com isoflurano. Foram obtidas imagens dos membros pélvicos nos planos sagital e transverso. Os bloqueios NC e NF guiados por um estimulador de nervos foram realizados com bupivacaína 0,5 % (0,1 mL/kg por ponto). As sequências da RM foram repetidas após cada bloqueio e as imagens analisadas de acordo com a distribuição (1; em contato com nervo ou 0; sem contato com o nervo alvo), localização da bupivacaína e presença ou ausência de hematoma e lesões nervosas. Na segunda fase do estudo, seis gatos adultos foram sedados com dexmedetomidina (25 µg/kg) e receberam os bloqueios NC e NF com 0,1 mL/kg de um dos tratamentos: salina 0,9% (CONTROLE), bupivacaína (0,46%; BUPI), bupivacaína e dexmedetomidina (1 µg/kg; BUPI-DEX) ou bupivacaína e buprenorfina (2,5 µg/kg; BUPI-BUPRE). A sedação foi revertida com atipamezole (250 µg/kg). Os escores de sedação, limiar de retirada do membro, capacidade de deambulação e resposta ao pinçamento digital foram avaliados até 24 horas após os bloqueios. De acordo com as imagens da RM, cinco de seis injeções do NC tiveram escore 1. O comprimento do NC em contato com a bupivacaína foi 25 ± 11 mm. Todas as injeções do NF tiveram escore 1. Em uma das injeções, a bupivacaína foi depositada distal à bifurcação do NF e do nervo safeno, apenas sobre o ramo motor do NF. Não foram observadas lesões nervosas e hemorragias. A técnica promoveu uma dispersão adequada e o volume foi considerado suficiente. Variações quanto à localização e distribuição do injetado poderiam explicar diferenças no bloqueio motor e sensitivo no contexto clínico. Todos os animais tratados com anestésico local demonstraram diminuição na função motora e alterações na antinocicepção. A capacidade de deambulação foi reduzida no tratamento BUPI de 30 min a 2 horas, no BUPI-DEX entre 1 e 2 horas e no BUPIBUPRE às 2h (p < 0,05). O bloqueio motor foi observado entre 1 e 3 horas. A analgesia, determinada pelo limiar de retirada do membro no tratamento BUPI foi maior de 1 a 6 horas em relação ao CONTROLE (p < 0,05) e atingiu valores acima de 2,4 N de 1 a 4 horas nos tratamentos BUPI-DEX e BUPI-BUPRE e de 1 a 8 horas nos animais que receberam o tratamento BUPI. As doses de buprenorfina e dexmedetomidina utilizadas como adjuvantes não aumentaram a magnitude e duração dos bloqueios dos NC e NF em gatos
Title in English
Sciatic and femoral nerve blocks in cats: evaluation of bupivacaine distribution under nuclear magnetic resonance and antinociceptive assessment
Keywords in English
Analgesia
Anesthesia
Feline
Local anesthesic
Abstract in English
Peripheral nerve blocks are practic, effective and widely used for the perioperative pain management, however studies in cats are scarce. The aim of this study was to evaluate the distribution of bupivacaine after sciatic (ScN) and femoral nerve (FN) blocks in cats using magnetic resonance imaging (MRI) and to determine the feasibility, effectiveness and duration of antinociception after ScN and FN blocks using bupivacaine alone, or in combination with either dexmedetomidine or buprenorphine. In the first phase of the study, six adult cats were anesthetized with isoflurane and underwent MRI. Transverse and sagittal plan sequences of pelvic limbs were obtained. The ScN and FN blocks were performed using an electric nerve stimulator-guided technique and bupivacaine 0.5% (0.1 mL/kg per site). The MRI sequences were repeated after each block and the images were analyzed according to the distribution (1; in contact with the nerve or 0; not in contact with the target nerve), bupivacaine location and presence or absence of hematomas and nerve injuries. In the second phase of the study, six adult cats were sedated with dexmedetomidine (25 µg/kg) and received the ScN and FN blocks with 0.1 mL/kg of one of the treatments: saline 0.9% (CONTROL), bupivacaine (0.46%; BUPI), bupivacaine and dexmedetomidine (1 µg/kg; BUPI-DEX) or bupivacaine and buprenorphine (2.5 µg/kg; BUPI-BUPRE). Atipamezole (250 µg/kg) was administered for reversal of sedation. Sedation scores, paw withdrawal thresholds, ability to walk and response to toe pinch were evaluated up to 24 hours after the blocks. According to MRI, five out of six ScN injections had distribution score of 1. Mean ± SD length of the ScN in contact with bupivacaine was 25 ± 11 mm. All FN injections had distribution score of 1. In one injection (FN), bupivacaine was administered distal to the bifurcation between the femoral and saphenous nerve and over the motor branch of FN. Nerve injury or acute hemorrhage were not observed. Nerve stimulator-guided ScN and FN injections produced a reliable bupivacaine spread over the target nerves and the volume was considered sufficient. Individual variability in regards to the injectate location may explain differences in sensory and motor blockade in the clinical setting. All local anesthetic-treated animals had motor function impairment and changes in antinociception. Walking ability was impaired in BUPI from 30 min to 2 hours, in BUPI-DEX between 1 and 2 hours and in BUPI-BUPRE at 2h (p < 0.05). Motor blockade was observed between 1 and 3 hours. Analgesia, determined by paw withdraw threshold, was higher from 1 to 6 hours in BUPI compared to CONTROL (p < 0.05) and reached values greater than 2.4 N from 1 to 4 hours in BUPI-DEX and BUPI-BUPRE and from 1 to 8 hours in BUPI. The chosen doses of buprenorphine and dexmedetomidine as adjuvant drugs did not enhance the magnitude and duration of the ScN and NF blocks in cats
 
WARNING - Viewing this document is conditioned on your acceptance of the following terms of use:
This document is only for private use for research and teaching activities. Reproduction for commercial use is forbidden. This rights cover the whole data about this document as well as its contents. Any uses or copies of this document in whole or in part must include the author's name.
Publishing Date
2016-10-14
 
WARNING: Learn what derived works are clicking here.
All rights of the thesis/dissertation are from the authors
CeTI-SC/STI
Digital Library of Theses and Dissertations of USP. Copyright © 2001-2024. All rights reserved.