Estudo com anestesia com remifentanil e isoflurano em cães: efeito redutor sobre a concentração alveolar mínima (CAM) e avaliação hemodinâmica
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Data
2007-12-14
Autores
Monteiro, Eduardo Raposo [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O efeito do remifentanil sobre a concentração alveolar mínima do isoflurano (CAMISO) foi estudado em seis cães com peso médio de 27,7±4,3 kg. Os animais foram anestesiados com isoflurano sob ventilação mecânica, mantendo-se normocapnia (PaCO2 média: 38,5 mm Hg) e normotermia (temperatura corpórea média: 38,1oC). A CAMISO, determinada por meio da estimulação nociceptiva (50V/50Hz/10ms) do membro torácico, foi mensurada antes (basal), durante a infusão contínua de diferentes doses de remifentanil (0,15; 0,30; 0,60 e 0,90 μg/kg/min) e aproximadamente 80 minutos após o término da infusão do opióide. Após um intervalo de 7 dias, a CAMISO foi determinada às 2, 4 e 6 horas após o início da infusão de 0,15 μg/kg/min de remifentanil. As variáveis foram analisadas por meio de ANOVA seguida pelo teste de Tukey ou Dunnett (P<0,05). A CAMISO redeterminada ao término da infusão (1,22±0,20%) não diferiu da CAMISO basal (1,38±0,20%). Os valores da CAMISO foram significativamente mais baixos nas três maiores taxas de infusão em relação à menor (0,15 μg/kg/min). Observou-se redução significativa da CAMISO com todas as taxas de infusão de remifentanil (reduções percentuais em relação ao valor basal de 43±10%, 59±10%, 66±9% e 71±9% para as taxas de 0,15; 0,30; 0,60 e 0,90 μg/kg/min, respectivamente). Embora o valor da CAMISO não tenha diferido entre as taxas de infusão de 0,30; 0,60 e 0,90 μg/kg/min, a percentagem de redução na CAMISO foi maior com a dose de 0,90 em relação à dose de 0,30 μg/kg/min. A CAMISO não se modificou ao longo do tempo com a taxa de 0,15 μg/kg/min. Em uma segunda etapa de experimentos, os efeitos hemodinâmicos da anestesia com remifentanil e isoflurano foram estudados nos mesmos cães. Adicionalmente, amostras de sangue foram colhidas para mensurar a concentração plasmática de arginina vasopressina...
The isoflurane-sparing effect of remifentanil on the minimum alveolar concentration (MACISO) was evaluated in six dogs weighing 27.7±4.3 kg. The dogs were anesthetized with isoflurane and mechanically ventilated to maintain eucapnia (mean PaCO2: 38.5 mm Hg). Mean core temperature was kept at 38.1oC. Noxious stimulation (50V/50Hz/10ms) was applied to the thoracic limb for determination of MACISO before (baseline), during different infusion rates of remifentanil (0.15, 0.30, 0.60 and 0.90 μg/kg/min) and approximately 80 minutes after stopping remifentanil infusion. After a 7-day washout period, MACISO was determined within 2, 4 and 6 hours of a constant rate infusion of remifentanil (0.15 μg/kg/min). Data were analyzed by ANOVA followed by a Tukey or Dunnett test whenever appropriate (P<0.05). After stopping remifentanil infusion, MACISO (1.22±0.20%) did not differ from baseline MACISO (1.38%±0.20). Mean values of MACISO were significantly lower during the infusion rates of 0.30, 0.60 and 0.90 μg/kg/min compared to the lowest infusion rate (0.15 μg/kg/min). All infusion rates of remifentanil decreased MACISO significantly (percentage reductions compared to baseline MACISO were 43±10%, 59±10%, 66±9% and 71±9% for the infusion rates of 0.15, 0.30, 0.60 and 0.90 μg/kg/min, respectively). Although MACISO did not differ among the three highest infusion rates of remifentanil, the percentage reduction in MACISO was significantly greater during 0.90 μg/kg/min compared to 0.30 μg/kg/min. The effect of remifentanil on MACISO was stable during a prolonged constant rate infusion (0.15 μg/kg/min). In a second set of experiments, the hemodynamic changes during remifentanil-isoflurane anesthesia were evaluated in the same six dogs. Additionally, blood samples were collected to determine plasma concentrations of arginine vasopressin. In a randomized cross-over design, the dogs received... (Complete abstract click electronic access below)
The isoflurane-sparing effect of remifentanil on the minimum alveolar concentration (MACISO) was evaluated in six dogs weighing 27.7±4.3 kg. The dogs were anesthetized with isoflurane and mechanically ventilated to maintain eucapnia (mean PaCO2: 38.5 mm Hg). Mean core temperature was kept at 38.1oC. Noxious stimulation (50V/50Hz/10ms) was applied to the thoracic limb for determination of MACISO before (baseline), during different infusion rates of remifentanil (0.15, 0.30, 0.60 and 0.90 μg/kg/min) and approximately 80 minutes after stopping remifentanil infusion. After a 7-day washout period, MACISO was determined within 2, 4 and 6 hours of a constant rate infusion of remifentanil (0.15 μg/kg/min). Data were analyzed by ANOVA followed by a Tukey or Dunnett test whenever appropriate (P<0.05). After stopping remifentanil infusion, MACISO (1.22±0.20%) did not differ from baseline MACISO (1.38%±0.20). Mean values of MACISO were significantly lower during the infusion rates of 0.30, 0.60 and 0.90 μg/kg/min compared to the lowest infusion rate (0.15 μg/kg/min). All infusion rates of remifentanil decreased MACISO significantly (percentage reductions compared to baseline MACISO were 43±10%, 59±10%, 66±9% and 71±9% for the infusion rates of 0.15, 0.30, 0.60 and 0.90 μg/kg/min, respectively). Although MACISO did not differ among the three highest infusion rates of remifentanil, the percentage reduction in MACISO was significantly greater during 0.90 μg/kg/min compared to 0.30 μg/kg/min. The effect of remifentanil on MACISO was stable during a prolonged constant rate infusion (0.15 μg/kg/min). In a second set of experiments, the hemodynamic changes during remifentanil-isoflurane anesthesia were evaluated in the same six dogs. Additionally, blood samples were collected to determine plasma concentrations of arginine vasopressin. In a randomized cross-over design, the dogs received... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Cão - Anestesia, Anestesia veterinaria, Remifentanil, Minimum alveolar concentration, Hemodynamic changes
Como citar
MONTEIRO, Eduardo Raposo. Estudo com anestesia com remifentanil e isoflurano em cães: efeito redutor sobre a concentração alveolar mínima (CAM) e avaliação hemodinâmica. 2007. 147 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Medicina de Botucatu, 2007.