Objectives To compare the anaesthetic, analgesic and cardiorespiratory effects of intramuscular medetomidine and ketamine administered alone or combined with morphine or tramadol for orchiectomy in cats. Study design Randomised, blinded, prospective clinical study. Animals Thirty client owned healthy cats. Materials and methods Cats received a combination of medetomidine (60 μg kg-1) and ketamine (10 mg kg-1) alone (MedK) or combined with morphine (0.2 mg kg-1) (MedKM) or tramadol (2 mg kg-1) (MedKT) intramuscularly. Time of different events and physiological parameters were recorded by a blinded researcher. Pre-surgery arterial and venous blood gases were measured. Heart rate (HR), respiration rate (fR), systolic arterial blood pressure (SABP), peripheral haemoglobin saturation (SpO2) and end-tidal carbon dioxide tension (PETCO2) were recorded every 5 minutes of general anaesthesia and at each surgical stage. Post-operative analgesia was evaluated with a visual analogue scale, a multidimensional composite scoring system and a rigid tip von Frey mechanical threshold device every hour from 3 to 8 hours post-injection of the initial combination of drugs. Data were analysed with a linear mixed model, Kruskal Wallis or Chi-square tests (p < 0.05). Results Median (range) induction and recovery times (minutes) were not significantly (P = 0.125) different among the three combinations: 5.6 (2.7, 8.0), 7.4 (5.1, 9.6) and 8 (5.8, 14.9) for induction and 128 (95, 143), 166 (123, 210) and 143 (123, 180) for recovery, with MedK, MedKT and MedKM, respectively. All three combinations caused similar low partial pressure of arterial oxygen (PaO2) values (mean ± SD: 66.2 ± 1.7 mmHg). Surgery had a significant effect on SABP (p < 0.001), SpO2 (p < 0.001), fR (p = 0.003) and HR (p = 0.002), which increased; and PETCO2 (p = 0.003), which decreased, with all combinations. Non-significant differences were found in pain scores and von Frey results among treatments; however, the von Frey changes over time did vary by treatment (p < 0.001) with the MedK group returning to baseline values more rapidly than MedKM and MedKT. None of the cats required rescue analgesics. Conclusion and clinical relevance All three protocols provide adequate anaesthesia and analgesia for orchiectomy in cats. However, rescue intervention to maintain surgical anaesthesia such as isoflurane may be required in some cats. Oxygen should be supplemented. / Dissertation (MMedVet)--University of Pretoria, 2013 / gm2014 / Companion Animal Clinical Studies / unrestricted

Orientador: Carlos Augusto Araújo Valadão / Banca: Paulo Sérgio Patto dos Santos / Banca: Carmen Esther Grumadas Machado / Resumo: Avaliaram-se, 8 equinos, sob anestesia geral inalatoria com isofluorano (1CAM) e infusao continua de xilazina (0,35mg/kg/h) ou medetomidina (3,5£gg/kg/h), em relacao a frequencia cardiaca, ritmo cardiaco, frequencia respiratoria, pressao arterial, hemogasometria arterial, tonus muscular e temperatura, nos tempos T0 (imediatamente antes do inicio da infusao continua) e T10 ao T60 (intervalos de 10 minutos, apos inicio da infusao continua), alem da qualidade da tranquilizacao, inducao e recuperacao anestesica. Os dados parametricos foram submetidos a analise de variancia para repeticoes multiplas, seguido pelo teste de Student-Newman-Keuls e, entre os grupos, teste-t de Student. Para os dados nao parametricos utilizou-se teste de Friedman e entre os grupos, teste de Mann-Whitney (p-T0,05). Houve reducao da frequencia cardiaca e da temperatura e elevacao da pressao arterial media. A paCO2 (no GM) e a ctCO2 elevaram-se e a paO2 mostrou-se maior no GM que no GX. Os dois farmacos mostraram-se eficientes para tranquilizacao, mas o GM demonstrou melhor miorrelaxamento e qualidade de inducao anestesica que o GX. Da mesma forma, a recuperacao anestesica apresentada pelo GM foi de melhor qualidade, embora mais prolongada. Conclui-se que a infusao continua de doses equipotentes de xilazina e medetomidina, durante anestesia geral inalatoria, com isofluorano, em equinos, promove alteracoes cardiocirculatorias, respiratorias e hemogasometricas discretas e equivalentes. / Abstract: Eight equines under inhalatory general anesthesia with isoflurane (1MAC) and continuous infusion of xylazine (0.35mg/kg/h) or medetomidine (3.5-Êg/kg/h) were evaluated for heart rate and rhythm, respiratory rate, arterial blood pressure, arterial blood gas analysis, muscle relaxation and temperature immediately before the beginning of the continuous infusion (T0) and in intervals of 10 minutes after the beginning of the continuous infusion (T10 to T60) and also for tranquillization, induction and anesthetic recovery quality. The parametric data were evaluated by one way repeated measures ANOVA, followed by Student-Newman-Keuls and between groups Student t-test. Non-parametric data were evaluated by Friedman test and between groups Mann-Whitney test (p.0.05). Heart rate and temperature decreased and mean Heart rate and temperature decreased and mean aaarrrttteeerrriiiaaalll ppprrreeessssssuuurrreee increased. PaCO2 (in GM) and ctCO2 increased and GM showed a higher paO2 than GX. Both drugs were efficient in tranquilization but GM showed better muscle relaxation and induction quality than GX. In the same way, GM presented better anesthetic recovery even though it took more time. We conclude that equipotent doses of continuous infusion of medetomidine and xylazine during inhalatory general anesthesia with isoflurane in equines promote slight and equivalent cardiocirculatory, respiratory and arterial blood gases changes. / Mestre

Made available in DSpace on 2014-06-11T19:23:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2006-10-20Bitstream added on 2014-06-13T20:28:10Z : No. of bitstreams: 1 doria_rgs_me_jabo.pdf: 844929 bytes, checksum: 66ab2b4d51e336752ba5ac561a267860 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Avaliaram-se, 8 equinos, sob anestesia geral inalatoria com isofluorano (1CAM) e infusao continua de xilazina (0,35mg/kg/h) ou medetomidina (3,5£gg/kg/h), em relacao a frequencia cardiaca, ritmo cardiaco, frequencia respiratoria, pressao arterial, hemogasometria arterial, tonus muscular e temperatura, nos tempos T0 (imediatamente antes do inicio da infusao continua) e T10 ao T60 (intervalos de 10 minutos, apos inicio da infusao continua), alem da qualidade da tranquilizacao, inducao e recuperacao anestesica. Os dados parametricos foram submetidos a analise de variancia para repeticoes multiplas, seguido pelo teste de Student-Newman-Keuls e, entre os grupos, teste-t de Student. Para os dados nao parametricos utilizou-se teste de Friedman e entre os grupos, teste de Mann-Whitney (p-T0,05). Houve reducao da frequencia cardiaca e da temperatura e elevacao da pressao arterial media. A paCO2 (no GM) e a ctCO2 elevaram-se e a paO2 mostrou-se maior no GM que no GX. Os dois farmacos mostraram-se eficientes para tranquilizacao, mas o GM demonstrou melhor miorrelaxamento e qualidade de inducao anestesica que o GX. Da mesma forma, a recuperacao anestesica apresentada pelo GM foi de melhor qualidade, embora mais prolongada. Conclui-se que a infusao continua de doses equipotentes de xilazina e medetomidina, durante anestesia geral inalatoria, com isofluorano, em equinos, promove alteracoes cardiocirculatorias, respiratorias e hemogasometricas discretas e equivalentes. / Eight equines under inhalatory general anesthesia with isoflurane (1MAC) and continuous infusion of xylazine (0.35mg/kg/h) or medetomidine (3.5-Êg/kg/h) were evaluated for heart rate and rhythm, respiratory rate, arterial blood pressure, arterial blood gas analysis, muscle relaxation and temperature immediately before the beginning of the continuous infusion (T0) and in intervals of 10 minutes after the beginning of the continuous infusion (T10 to T60) and also for tranquillization, induction and anesthetic recovery quality. The parametric data were evaluated by one way repeated measures ANOVA, followed by Student-Newman-Keuls and between groups Student t-test. Non-parametric data were evaluated by Friedman test and between groups Mann-Whitney test (p.0.05). Heart rate and temperature decreased and mean Heart rate and temperature decreased and mean aaarrrttteeerrriiiaaalll ppprrreeessssssuuurrreee increased. PaCO2 (in GM) and ctCO2 increased and GM showed a higher paO2 than GX. Both drugs were efficient in tranquilization but GM showed better muscle relaxation and induction quality than GX. In the same way, GM presented better anesthetic recovery even though it took more time. We conclude that equipotent doses of continuous infusion of medetomidine and xylazine during inhalatory general anesthesia with isoflurane in equines promote slight and equivalent cardiocirculatory, respiratory and arterial blood gases changes.

Made available in DSpace on 2014-06-11T19:23:43Z (GMT). No. of bitstreams: 0 Previous issue date: 2009-06-26Bitstream added on 2014-06-13T19:30:10Z : No. of bitstreams: 1 perotta_jh_me_jabo.pdf: 623926 bytes, checksum: fd1742e9755f2d3558b2e7aae947f3e1 (MD5) / Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) / Entre os animais domésticos, os equinos são os que apresentam maior taxa de mortalidade sob intervenção anestésica, sendo a principal causa a depressão cardiovascular. Os agonistas 2 produzem efeitos sedativos e analgésicos, porém, causam hipertensão transitória seguida de hipotensão, bradicardia com redução do débito cardíaco, às vezes, associada ao bloqueio atrioventricular de segundo grau. A medetomidina é um agonista 2 de alta especificidade produzindo sedação e analgesia mais profundas e duradouras em relação aos outros agentes desta classe. A hioscina minimiza os efeitos cardíacos dos agonistas 2, com discreto efeito sobre a motilidade gastrintestinal dos equinos. Avaliaram-se os efeitos clínicos e comportamentais induzidos pela injeção de medetomidina em oito equinos pretratados com hioscina por via IV ou IM ou solução de NaCl 0,9% alocados em três grupos: GSFM (grupo solução de NaCl 0,9% seguida de medetomidina, dose 7,5 g/kg); GHivM (grupo hioscina IV, dose de 0,14 mg/kg, seguida de medetomidina); e GHimM (hioscina IM, dose de 0,3 mg/kg, seguida de medetomidina). O segundo fármaco foi aplicado cinco minutos após o primeiro. A hioscina, tanto por via IV quanto por via IM elevou significativamente a FC, as pressões arteriais e o débito cardíaco. Houve diminuição da PA no GHivM. Houve diminuição significativa na f e na altura da cabeça nos três grupos. Não houve diferenças significativas na PaO2 e PaCO2. A hioscina diminuiu o tempo de sedação, sendo este efeito dependente de dose. A hioscina, tanto por via intravenosa quanto por via intramuscular preveniu os efeitos cardiovasculares da medetomidina, sendo que por via intramuscular, este efeito foi mais tardio, porém de maior duração. / Between domestic animals, the horses have the biggest mortality rate during general anaesthesia, and the main cause is the cardiovascular depression. The 2 agonist produces sedative and analgesic effects, but they produce transitory hypertension followed by hypotension, bradycardia with decrease in cardiac output, and, sometimes, second-degree atrioventricular block. The medetomidine is a high specificity the 2 agonist producing sedation and analgesia more profound than other being more potent than the other 2 agonist. The hyoscine minimizes the cardiovascular effects of 2 agonist and has minimal effects over the gastrointestinal tract. We evaluated the behavioural and clinical effects of medetomidine in eight horses pre-treated with IV or IM hyoscine put in three groups: GSFM (group NaCl 0,9% solution before medetomidine, at dose 7.5 g/kg); GHivM (group IV hyoscine, at dose 0.14 mg/kg, before medetomidine); GHimM (group IM hyoscine, at dose 0.3 mg/kg, before medetomidine). The second drug was administered five minutes after first. The IV and IM hyoscine increased significantly the heart rate, the arterial pressures and the cardiac output. Fall in MAP had occurred late in the group GHivM. There were significantly decrease in respiration rate and head height in all groups. There were no changes in partial pressure of oxygen and carbonic gas. The hioscyne reduced the sedation time, dose-dependent. Both intravenous and intramuscular hioscyne administrations prevented the cardiovascular effects of medetomidine. The intramuscular route started your effect late, but lasted more than the intravenous administration.

Orientador: Carlos Augusto Araújo Valadão / Banca: Anderson Farias / Banca: Francisco José Teixeira Neto / Resumo: Entre os animais domésticos, os equinos são os que apresentam maior taxa de mortalidade sob intervenção anestésica, sendo a principal causa a depressão cardiovascular. Os agonistas 2 produzem efeitos sedativos e analgésicos, porém, causam hipertensão transitória seguida de hipotensão, bradicardia com redução do débito cardíaco, às vezes, associada ao bloqueio atrioventricular de segundo grau. A medetomidina é um agonista 2 de alta especificidade produzindo sedação e analgesia mais profundas e duradouras em relação aos outros agentes desta classe. A hioscina minimiza os efeitos cardíacos dos agonistas 2, com discreto efeito sobre a motilidade gastrintestinal dos equinos. Avaliaram-se os efeitos clínicos e comportamentais induzidos pela injeção de medetomidina em oito equinos pretratados com hioscina por via IV ou IM ou solução de NaCl 0,9% alocados em três grupos: GSFM (grupo solução de NaCl 0,9% seguida de medetomidina, dose 7,5 g/kg); GHivM (grupo hioscina IV, dose de 0,14 mg/kg, seguida de medetomidina); e GHimM (hioscina IM, dose de 0,3 mg/kg, seguida de medetomidina). O segundo fármaco foi aplicado cinco minutos após o primeiro. A hioscina, tanto por via IV quanto por via IM elevou significativamente a FC, as pressões arteriais e o débito cardíaco. Houve diminuição da PA no GHivM. Houve diminuição significativa na f e na altura da cabeça nos três grupos. Não houve diferenças significativas na PaO2 e PaCO2. A hioscina diminuiu o tempo de sedação, sendo este efeito dependente de dose. A hioscina, tanto por via intravenosa quanto por via intramuscular preveniu os efeitos cardiovasculares da medetomidina, sendo que por via intramuscular, este efeito foi mais tardio, porém de maior duração. / Abstract: Between domestic animals, the horses have the biggest mortality rate during general anaesthesia, and the main cause is the cardiovascular depression. The 2 agonist produces sedative and analgesic effects, but they produce transitory hypertension followed by hypotension, bradycardia with decrease in cardiac output, and, sometimes, second-degree atrioventricular block. The medetomidine is a high specificity the 2 agonist producing sedation and analgesia more profound than other being more potent than the other 2 agonist. The hyoscine minimizes the cardiovascular effects of 2 agonist and has minimal effects over the gastrointestinal tract. We evaluated the behavioural and clinical effects of medetomidine in eight horses pre-treated with IV or IM hyoscine put in three groups: GSFM (group NaCl 0,9% solution before medetomidine, at dose 7.5 g/kg); GHivM (group IV hyoscine, at dose 0.14 mg/kg, before medetomidine); GHimM (group IM hyoscine, at dose 0.3 mg/kg, before medetomidine). The second drug was administered five minutes after first. The IV and IM hyoscine increased significantly the heart rate, the arterial pressures and the cardiac output. Fall in MAP had occurred late in the group GHivM. There were significantly decrease in respiration rate and head height in all groups. There were no changes in partial pressure of oxygen and carbonic gas. The hioscyne reduced the sedation time, dose-dependent. Both intravenous and intramuscular hioscyne administrations prevented the cardiovascular effects of medetomidine. The intramuscular route started your effect late, but lasted more than the intravenous administration. / Mestre

Made available in DSpace on 2016-01-26T18:55:28Z (GMT). No. of bitstreams: 1 DISSERTACAO DEFINITIVA BIBLIOTECA 05_05.pdf: 469535 bytes, checksum: e48e2a39c7ec011f80647303b7c9db3a (MD5) Previous issue date: 2009-02-11 / The medetomidine is sedative and analgesic of the group of the a2 adrenergic agonist approved for dogs and cats, described now as more potent than the xylazine, an old agonist a2 adrenergic of veterinary use. The main difference among those two agonists is the selectivity to the receptors a2-adrenergics, being the medetomidine considered more selective, checking, therefore, larger sedative and analgesic potency. The reversion of the effects of a2-adrenergics is accomplished with the use of the a2-adrenergics antagonists, being the atipamezole the most efficient due to his largest selectivity. The objective of this work was to accomplish a comparative study of the effects of the medetomidine and xylazine in cats, and to prove the reversion of the induced effects of these two agonists with atipamezole. It was concluded that the medetomidine and the xylazine present similar effects in most of the appraised parameters, however the medetomidina induced hyperglycemia and sedation more accentuated than the xylazine. The atipamezole presented excellent effectiveness, antagonizing all of the effects induced by the medetomidine and the xylazine. / A medetomidina um sedativo e analgésico do grupo dos agonistas alfa2 adrenérgicos aprovada para cães e gatos, descrita atualmente como mais potente do que a xilazina, antiga agonista alfa2 adrenérgica de uso veterinário. A principal diferença entre esses dois agonistas é a seletividade aos receptores alfa2-adrenérgicos, sendo a medetomidina considerada mais seletiva, conferindo, portanto, maior potência sedativa e analgésica. A reversão dos efeitos dos agonistas alfa2-adrenérgicos é realizada com o uso dos antagonistas alfa2-adrenérgicos, sendo o atipamezole o mais eficiente devido a sua maior seletividade. O objetivo deste trabalho foi comparar os efeitos da medetomidina e xilazina em gatos, e comprovar a reversão desses efeitos induzidos por esses dois agonistas com atipamezole. Concluiu-se que a medetomidina e a xilazina apresentam efeitos semelhantes na maioria dos parâmetros avaliados, porém a medetomidina induziu hiperglicemia e sedação mais acentuada do que a xilazina. O atipamezole apresentou excelente eficácia, antagonizando todos os efeitos induzidos pela medetomidina e a xilazina.

Made available in DSpace on 2016-07-18T17:53:06Z (GMT). No. of bitstreams: 1 DISSERTACAO DEFINITIVA BIBLIOTECA 05_05.pdf: 469535 bytes, checksum: e48e2a39c7ec011f80647303b7c9db3a (MD5) Previous issue date: 2009-02-11 / The medetomidine is sedative and analgesic of the group of the a2 adrenergic agonist approved for dogs and cats, described now as more potent than the xylazine, an old agonist a2 adrenergic of veterinary use. The main difference among those two agonists is the selectivity to the receptors a2-adrenergics, being the medetomidine considered more selective, checking, therefore, larger sedative and analgesic potency. The reversion of the effects of a2-adrenergics is accomplished with the use of the a2-adrenergics antagonists, being the atipamezole the most efficient due to his largest selectivity. The objective of this work was to accomplish a comparative study of the effects of the medetomidine and xylazine in cats, and to prove the reversion of the induced effects of these two agonists with atipamezole. It was concluded that the medetomidine and the xylazine present similar effects in most of the appraised parameters, however the medetomidina induced hyperglycemia and sedation more accentuated than the xylazine. The atipamezole presented excellent effectiveness, antagonizing all of the effects induced by the medetomidine and the xylazine. / A medetomidina um sedativo e analgésico do grupo dos agonistas alfa2 adrenérgicos aprovada para cães e gatos, descrita atualmente como mais potente do que a xilazina, antiga agonista alfa2 adrenérgica de uso veterinário. A principal diferença entre esses dois agonistas é a seletividade aos receptores alfa2-adrenérgicos, sendo a medetomidina considerada mais seletiva, conferindo, portanto, maior potência sedativa e analgésica. A reversão dos efeitos dos agonistas alfa2-adrenérgicos é realizada com o uso dos antagonistas alfa2-adrenérgicos, sendo o atipamezole o mais eficiente devido a sua maior seletividade. O objetivo deste trabalho foi comparar os efeitos da medetomidina e xilazina em gatos, e comprovar a reversão desses efeitos induzidos por esses dois agonistas com atipamezole. Concluiu-se que a medetomidina e a xilazina apresentam efeitos semelhantes na maioria dos parâmetros avaliados, porém a medetomidina induziu hiperglicemia e sedação mais acentuada do que a xilazina. O atipamezole apresentou excelente eficácia, antagonizando todos os efeitos induzidos pela medetomidina e a xilazina.

Les effets cardiovasculaires des alpha-2 agonistes, particulièrement importants chez les chiens, limitent leur utilisation en pratique vétérinaire. La perfusion à débit constant (PDC) de ces drogues, comme la médétomidine (MED) permettrait un contrôle plus précis de ces effets. Les effets hémodynamiques de plusieurs doses de MED en PDC ont été évalués chez le chien. Lors de cette étude prospective, réalisée en double aveugle, 24 chiens en santé, ont reçu de façon aléatoire une des 6 doses de MED PDC (4 chiens par groupe). Les chiens ont été ventilés mécaniquement pendant une anesthésie minimale standardisée avec de l’isoflurane dans de l’oxygène. Une dose de charge (DC) de médétomidine a été administrée aux doses de 0.2, 0.5, 1.0, 1.7, 4.0 ou 12.0 µg/kg pendant 10 minutes, après laquelle la MED PDC a été injectée à une dose identique à celle de la DC pendant 60 minutes. L’isoflurane a été administré seul pendant une heure après l’administration d’une combinaison d’ISO et de MED PDC pendant 70 minutes. La fréquence cardiaque (FC), la pression artérielle moyenne (PAM) et l’index du débit cardiaque (IC) ont été mesurés. Des prélèvements sanguins ont permis d’évaluer le profil pharmacocinétique. D’après ces études, les effets hémodynamiques de la MED PDC pendant une anesthésie à l’isoflurane ont été doses-dépendants. L’IC a diminué progressivement alors que la dose de MED augmentait avec: 14.9 (12.7), 21.7 (17.9), 27.1 (13.2), 44.2 (9.7), 47.9 (8.1), and 61.2 (14.1) % respectivement. Les quatre doses les plus basses n’ont provoqué que des changements minimes et transitoires de la FC, de la PAM et de l’IC. La pharmacocinétique apparaît clairement dose-dépendante. De nouvelles expériences seront nécessaires afin d’étudier l’utilisation clinique de la MED PDC. / The cardiovascular effects of alpha-2 agonists, particularly pronounced in dogs, limit their use in veterinary practice. The use of these drugs, namely medetomidine (MED), by constant rate infusion (CRI), could allow more precise control of the cardiovascular effects. The haemodynamic responses of MED CRI at several dosages in dogs were investigated. In a prospective, blinded study, 24 healthy beagles randomly received one of 6 MED CRI regimens (4 dogs per regimen). Dogs were mechanically ventilated to maintain stable low-level isoflurane (ISO) anaesthesia in oxygen. A loading MED infusion was administered at 0.2, 0.5, 1.0, 1.7, 4.0 or 12.0 µg•kg-1 for 10 min, followed by maintenance CRI for 60 min providing identical dose amounts for all dogs (total duration for MED and ISO: 70 min). Isoflurane was then administered alone for an additional hour. Heart rate (HR), mean arterial blood pressure (MAP), and cardiac index (CI) were recorded. Blood sampling was performed to establish pharmacokinetic profiles. Based on this study, the hemodynamic effects of MED CRI during ISO anaesthesia were found to be dose-dependent. Baseline CI decreased dose-dependently as MED dose increased by: 14.9 (12.7), 21.7 (17.9), 27.1 (13.2), 44.2 (9.7), 47.9 (8.1), and 61.2 (14.1) % respectively. The four lowest dosages created limited and transient changes in HR, MAP, and CI. Pharmacokinetics were dose-dependent. Further investigations for perioperative use are warranted.

Les effets cardiovasculaires des alpha-2 agonistes, particulièrement importants chez les chiens, limitent leur utilisation en pratique vétérinaire. La perfusion à débit constant (PDC) de ces drogues, comme la médétomidine (MED) permettrait un contrôle plus précis de ces effets. Les effets hémodynamiques de plusieurs doses de MED en PDC ont été évalués chez le chien. Lors de cette étude prospective, réalisée en double aveugle, 24 chiens en santé, ont reçu de façon aléatoire une des 6 doses de MED PDC (4 chiens par groupe). Les chiens ont été ventilés mécaniquement pendant une anesthésie minimale standardisée avec de l’isoflurane dans de l’oxygène. Une dose de charge (DC) de médétomidine a été administrée aux doses de 0.2, 0.5, 1.0, 1.7, 4.0 ou 12.0 µg/kg pendant 10 minutes, après laquelle la MED PDC a été injectée à une dose identique à celle de la DC pendant 60 minutes. L’isoflurane a été administré seul pendant une heure après l’administration d’une combinaison d’ISO et de MED PDC pendant 70 minutes. La fréquence cardiaque (FC), la pression artérielle moyenne (PAM) et l’index du débit cardiaque (IC) ont été mesurés. Des prélèvements sanguins ont permis d’évaluer le profil pharmacocinétique. D’après ces études, les effets hémodynamiques de la MED PDC pendant une anesthésie à l’isoflurane ont été doses-dépendants. L’IC a diminué progressivement alors que la dose de MED augmentait avec: 14.9 (12.7), 21.7 (17.9), 27.1 (13.2), 44.2 (9.7), 47.9 (8.1), and 61.2 (14.1) % respectivement. Les quatre doses les plus basses n’ont provoqué que des changements minimes et transitoires de la FC, de la PAM et de l’IC. La pharmacocinétique apparaît clairement dose-dépendante. De nouvelles expériences seront nécessaires afin d’étudier l’utilisation clinique de la MED PDC. / The cardiovascular effects of alpha-2 agonists, particularly pronounced in dogs, limit their use in veterinary practice. The use of these drugs, namely medetomidine (MED), by constant rate infusion (CRI), could allow more precise control of the cardiovascular effects. The haemodynamic responses of MED CRI at several dosages in dogs were investigated. In a prospective, blinded study, 24 healthy beagles randomly received one of 6 MED CRI regimens (4 dogs per regimen). Dogs were mechanically ventilated to maintain stable low-level isoflurane (ISO) anaesthesia in oxygen. A loading MED infusion was administered at 0.2, 0.5, 1.0, 1.7, 4.0 or 12.0 µg•kg-1 for 10 min, followed by maintenance CRI for 60 min providing identical dose amounts for all dogs (total duration for MED and ISO: 70 min). Isoflurane was then administered alone for an additional hour. Heart rate (HR), mean arterial blood pressure (MAP), and cardiac index (CI) were recorded. Blood sampling was performed to establish pharmacokinetic profiles. Based on this study, the hemodynamic effects of MED CRI during ISO anaesthesia were found to be dose-dependent. Baseline CI decreased dose-dependently as MED dose increased by: 14.9 (12.7), 21.7 (17.9), 27.1 (13.2), 44.2 (9.7), 47.9 (8.1), and 61.2 (14.1) % respectively. The four lowest dosages created limited and transient changes in HR, MAP, and CI. Pharmacokinetics were dose-dependent. Further investigations for perioperative use are warranted.

Made available in DSpace on 2016-08-15T20:31:14Z (GMT). No. of bitstreams: 1 ArianaLCP_DISSERT.pdf: 3312068 bytes, checksum: ea8577abaac8f8961ca7e3a92407dbeb (MD5) Previous issue date: 2012-05-16 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / The objective was to verify the existence of potential associations between medetomidine and atipemazole in electroejaculation of peccaries anesthetized with propofol. The twelve peccary received the following treatments: control, none pre medication; medetomidine 40 microg.Kg-1 IV or atipemazole 200 microg.Kg-1 IV. All animals received 5 mg.Kg-1 IV propofol induction and maintenance of anesthesia. Were evaluated: heart rate, respiratory rate, systolic, diastolic, and mean blood pressure, temperature, blood gas and cortisol. For the semen evaluated the onset time of ejaculation, erection, and seminal variables. We analyzed the data by one way ANOVA for repeated measures followed by Tukey. P < 0.05 were considered significant. For semen, we obtained only a significant difference in sperm concentration between atipemazole (100.00 ± 25.96 x 106) and medetomidine (220.20 ± 49.74 x 106), yet both did not differ from controls (180.00 ± 50.71 x 106). Medetomidine promoted cardiovascular changes more significant. There was no significant difference in cortisol levels between the treatments compared. Atipamezole and medetomidine do not increase the peccary s erectile function. However, they influence the concentration of sperm and ejaculatory function in the peccary undergoing electroejaculation. Propofol alone, resulted in a more efficient anesthesia for peccary collection semen / Objetivou-se verificar a existência de potenciais associações entre medetomidina e atipemazole na eletroejaculação de catetos anestesiados com propofol. Os doze catetos receberam os tratamentos: controle, sem pré medicação; medetomidina 40 &#956;g.Kg -1IV ou atipemazole 200 &#956;g.Kg -1 IV. Todos os animais receberam propofol 5 mg.Kg -1 IV na indução e manutenção da anestesia. Foram avaliados: frequência cardíaca, respiratória, pressão arterial sistólica, diastólica, e média, temperatura, hemogasometria e cortisol. Em relação aos parâmetros reprodutivos, avaliou-se o tempo de latência da ejaculação, ereção, e variáveis seminais. Analisamos os dados por one way ANOVA para medidas repetidas seguidas por Tukey. P < 0,05 foram considerados significativos. Para o sêmen, obtive-se diferença significativa na concentração espermática entre atipemazole (100,00 ± 25,96 x 106) e medetomidina (220,20 ± 49,74 x 106), contudo ambos não diferiram estatisticamente do controle (180,00 ± 50,71 x 106). Medetomidina promoveu alterações cardiovasculares mais significativas. Não foram observadas diferenças significativas nos valores de cortisol entre os tratamentos comparados. Recuperação com propofol foi significativamente mais rápida. Os fármacos medetomidina e atipemazole não incrementam a função erétil de catetos. Entretanto, influenciam na concentração espermática e na função ejaculatória destes. O propofol isolado proporcionou uma anestesia mais eficiente na coleta de sêmen catetos submetidos à eletroejaculação.