Levomepromazina e acepromazina no bloqueio da arritmia induzida pela adrenalina em cães anestesiados pelo halotano
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Data
2002-06-01
Autores
Rezende, Márlis Langenegger de [UNESP]
Farias, Anderson [UNESP]
Bolzan, Aline Adriana [UNESP]
Ferreira, Wagner Luis [UNESP]
Léga, Elzylene [UNESP]
Nunes, Newton [UNESP]
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Editor
Universidade Federal de Santa Maria (UFSM)
Resumo
Com este experimento, objetivou-se comparar os efeitos antiarritmogênicos da levomepromazina e da acepromazina em cães anestesiados pelo halotano e submetidos a doses crescentes de adrenalina. Foram empregados 19 animais adultos, sadios, separados em dois grupos, sendo um de 10 (G1) e outro de 09 (G2). O G1 recebeu, por via intravenosa, levomepromazina, na dose de 1mg/kg, seguida 15 minutos após, pela aplicação de propofol, pela mesma via, na dose de 5 ± 1,3mg/kg. Procedeu-se à intubação orotraqueal e iniciou-se a administração de halotano, diluído em oxigênio, na concentração de 3 CAM (2,5 V%), em circuito anestésico semi-fechado. Decorridos 50 minutos da indução anestésica, iniciou-se a administração contínua, intravenosa, de solução de adrenalina a 4% em doses crescentes de 4, 5, 6, 7 e 8mig/kg/min, com incremento da dose a intervalos de 10 minutos. Para o G2, empregou-se a mesma metodologia, substituindo-se a levomepromazina pela acepromazina, na dose de 0,1mg/kg. A eletrocardiografia e as pressões arteriais (sistólica, diastólica e média) dos animais permaneceram sob monitoramento contínuo, com início imediatamente antes da aplicação dos fármacos e término ao final do período experimental. As colheitas dos valores numéricos tiveram início imediatamente antes da aplicação dos fármacos (M1), seguidas de novas mensurações realizadas nos momentos correspondentes às doses crescentes de adrenalina (4, 5, 6, 7, 8mig/kg/minuto; M2, M3, M4, M5, M6, respectivamente). Os valores obtidos na eletrocardiografia referem o número total de batimentos ventriculares ectópicos correspondentes às doses crescentes de adrenalina. Apenas um animal de cada grupo apresentou arritmia ventricular sustentada, sendo que o animal pré-tratado com acepromazina foi à óbito. Os resultados obtidos permitiram concluir que a levomepromazina e a acepromazina minimizam a arritmia ventricular induzida pela adrenalina, nas doses empregadas, em cães anestesiados pelo halotano. Complementarmente foi possível deduzir que o risco de óbito por uso de adrenalina em cães anestesiados com halotano é ainda menor quando se opta pelo pré-tratamento com levomepromazina.
The aim of this work was to compare the antiarrhythmogenic effects of levomepromazine and acepromazine, in dogs anesthetized with halothane, receiving increasing doses of epinephrine. For this purpose, 19 male and female healthy adult mixed breed dogs were divided in two groups, one with 10 (G1) and other with 09 (G2) animals. G1 received intravenously, 1mg/kg of levomepromazine, followed, 15 minutes later, by anesthetic induction with propofol (5 ± 1.3mg/kg). The intubation was proceeded, followed by imediate administration of halothane at 3 MAC (2.5 V%) through a semi-closed anesthetic circuit. After 50 minutes of the anesthetic induction, administration of 4% epinephrine solution had begun, with increasing doses of 4, 5, 6, 7 and 8mug/kg/min. The increment of the doses occurred at 10 minutes intervals. For G2 the same methodology was used, except that levomepromazine was replaced with 0.1mg/kg of acepromazine. Electrocardiography and arterial blood pressure (systolic, diastolic and mean) were continuously evaluated, starting immediately before the administration of the drugs and going on until the end of the experimental period. The measurements were made immediately before the administration of the drugs (M1), followed by new measurements related with the increasing doses of epinephrine (4, 5, 6, 7 and 8mug/kg/min; M2, M3, M4, M5 and M6 respectively). The electrocardiographic values obtained were referent to the total number of ventricular premature complexes, coincident with each epinephrine dose. Only one animal of each group presented sustained ventricular arrhythmia, and the animal pretreated with acepromazine died. These results allowed the conclusion that levomepromazine and acepromazine minimizes ventricular epinephrine-induced arrhythmia in dogs anesthetized with halotane. In addiction, the risk of death by epinephrine use in dogs anesthetized with halotane and pretreated with levomepromazine seems to be even lower.
The aim of this work was to compare the antiarrhythmogenic effects of levomepromazine and acepromazine, in dogs anesthetized with halothane, receiving increasing doses of epinephrine. For this purpose, 19 male and female healthy adult mixed breed dogs were divided in two groups, one with 10 (G1) and other with 09 (G2) animals. G1 received intravenously, 1mg/kg of levomepromazine, followed, 15 minutes later, by anesthetic induction with propofol (5 ± 1.3mg/kg). The intubation was proceeded, followed by imediate administration of halothane at 3 MAC (2.5 V%) through a semi-closed anesthetic circuit. After 50 minutes of the anesthetic induction, administration of 4% epinephrine solution had begun, with increasing doses of 4, 5, 6, 7 and 8mug/kg/min. The increment of the doses occurred at 10 minutes intervals. For G2 the same methodology was used, except that levomepromazine was replaced with 0.1mg/kg of acepromazine. Electrocardiography and arterial blood pressure (systolic, diastolic and mean) were continuously evaluated, starting immediately before the administration of the drugs and going on until the end of the experimental period. The measurements were made immediately before the administration of the drugs (M1), followed by new measurements related with the increasing doses of epinephrine (4, 5, 6, 7 and 8mug/kg/min; M2, M3, M4, M5 and M6 respectively). The electrocardiographic values obtained were referent to the total number of ventricular premature complexes, coincident with each epinephrine dose. Only one animal of each group presented sustained ventricular arrhythmia, and the animal pretreated with acepromazine died. These results allowed the conclusion that levomepromazine and acepromazine minimizes ventricular epinephrine-induced arrhythmia in dogs anesthetized with halotane. In addiction, the risk of death by epinephrine use in dogs anesthetized with halotane and pretreated with levomepromazine seems to be even lower.
Descrição
Palavras-chave
Anesthesia, phenothiazines, antiarrhythmics, Anestesia, fenotiazinas, antiarritmicos
Como citar
Ciência Rural. Universidade Federal de Santa Maria (UFSM), v. 32, n. 3, p. 433-438, 2002.