Efeitos da administração peridural de neostigmina associada ou não a clonidina sobre a concentração alveolar mínima do isoflurano em cães
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Data
2010-02-22
Autores
Sisto, Renata Kerche Alvaides [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Os agentes anticolinesterásicos (neostigmina), quando associados com agonistas de receptores alfa-2 adrenérgicos (clonidina) pela via espinhal, resultam sinergismo no que se refere à analgesia promovida em ratos, ovinos e humanos. Na presente pesquisa, formulou-se a hipótese de que a administração peridural de neostigmina potencializaria a redução da concentração alveolar mínima (CAM) do isoflurano proporcionada pela clonidina peridural em cães. Seis cadelas hígidas (14,9 ± 2,9 kg) foram anestesiadas com isoflurano em 3 ocasiões distintas, com intervalo de 7 dias. Durante as anestesias foi empregada a ventilação controlada a pressão para prevenção da hipercapnia (PaCO2 > 45 mmHg) e a temperatura esofágica foi mantida entre 37,5 a 38,5oC por meios de aquecimento artificiais. Em cada anestesia, os animais receberam aleatoriamente 1 de 3 tratamentos pela via peridural: neostigmina (10 μg/kg), clonidina (20 μg/kg), ou a associação clonidina (20 μg/kg) e neostigmina (10 μg/kg). A CAM do isoflurano, mensurada por meio de estimulação nociceptiva do membro pélvico (50 V, 50 Hz, 10 ms), foi registrada após 2 horas da indução da anestesia (CAM basal) e após 2,5 e 5 horas da administração dos tratamentos peridurais. Em um dos animais, tanto a clonidina como a clonidina/neostigmina resultou em elevação paradoxal da CAM (8-9 %). Nos demais animais estudados (n = 5), os valores de CAM basal (média ± desvio padrão) foram de 1,49 ± 0,26, 1,51 ± 0,23 e 1,49 ± 0,26 vol%, nos tratamentos clonidina, neostigmina e clonidina/neostigmina, respectivamente, não havendo diferença entre tratamentos. As reduções da CAM observadas após a administração peridural de neostigmina não foram significativas (p < 0,05) (reduções percentuais de 11 ± 5% e 8 ± 9% após 2,5 e 5 horas, respectivamente). Houve redução significativa da CAM após a administração peridural de...
Spinal administration of anticholinesterase drugs (neostigmine) in combination with alpha-2 adrenergic receptor agonists (clonidine) results in a synergistic analgesic effect in rats, sheep and humans. The hypothesis of the present study was that the epidural administration of neostigmine would enhance the isoflurane minimum alveolar concentration (MAC) reduction induced by the epidural injection of clonidine in dogs. Six healthy bitches (14,9 ± 2,0 kg ) were anesthetized with isoflurane on 3 distinct occasions, with 7 day intervals among experiments. During the anesthetic episodes, animals were maintained under pressure controlled ventilation to prevent hypercapnia (PaCO2 > 45 mmHg) and esophageal temperature was maintained between 37.5 and 38.5 oC by means of artificial heating devices. During each anesthetic, animals were randomly allocated to receive 1 of 3 epidural treatments: neostigmine (10 μg/kg), clonidine (20 μg/kg), or the combination of clonidine (20 μg/kg) and neostigmine (10 μg/kg). Isoflurane MAC, determined by means of electric stimulation of the pelvic limb (50 V, 50 Hz, 10 ms), was recorded 2 hours after induction of anesthesia (baseline MAC) and 2.5 and 5 hours after epidural injections. In 1 of the animals, clonidine and clonidine/neostigmine caused paradoxical increases in MAC (8-9 % increases). For the remaining animals (n = 5), baseline MAC values (mean ± standard deviation) were 1.49 ± 0.26, 1.51 ± 0.23 e 1.49 ± 0.26 vol%, in the clonidine, neostigmine, and clonidine/neostigmine treatments, respectively. Baseline MAC did not differ among treatments. The isoflurane MAC reductions recorded after epidural injection of neostigmine were not significant (p < 0.05) (percent reductions of 11 ± 5% and 8 ± 9% after 2.5 and 5 hours respectively). The MAC reductions observed after epidural injection of clonidine (35 ± 9% and 22 ± 14% after 2.5 and 5 hours, ... (Complete abstract click electronic access below)
Spinal administration of anticholinesterase drugs (neostigmine) in combination with alpha-2 adrenergic receptor agonists (clonidine) results in a synergistic analgesic effect in rats, sheep and humans. The hypothesis of the present study was that the epidural administration of neostigmine would enhance the isoflurane minimum alveolar concentration (MAC) reduction induced by the epidural injection of clonidine in dogs. Six healthy bitches (14,9 ± 2,0 kg ) were anesthetized with isoflurane on 3 distinct occasions, with 7 day intervals among experiments. During the anesthetic episodes, animals were maintained under pressure controlled ventilation to prevent hypercapnia (PaCO2 > 45 mmHg) and esophageal temperature was maintained between 37.5 and 38.5 oC by means of artificial heating devices. During each anesthetic, animals were randomly allocated to receive 1 of 3 epidural treatments: neostigmine (10 μg/kg), clonidine (20 μg/kg), or the combination of clonidine (20 μg/kg) and neostigmine (10 μg/kg). Isoflurane MAC, determined by means of electric stimulation of the pelvic limb (50 V, 50 Hz, 10 ms), was recorded 2 hours after induction of anesthesia (baseline MAC) and 2.5 and 5 hours after epidural injections. In 1 of the animals, clonidine and clonidine/neostigmine caused paradoxical increases in MAC (8-9 % increases). For the remaining animals (n = 5), baseline MAC values (mean ± standard deviation) were 1.49 ± 0.26, 1.51 ± 0.23 e 1.49 ± 0.26 vol%, in the clonidine, neostigmine, and clonidine/neostigmine treatments, respectively. Baseline MAC did not differ among treatments. The isoflurane MAC reductions recorded after epidural injection of neostigmine were not significant (p < 0.05) (percent reductions of 11 ± 5% and 8 ± 9% after 2.5 and 5 hours respectively). The MAC reductions observed after epidural injection of clonidine (35 ± 9% and 22 ± 14% after 2.5 and 5 hours, ... (Complete abstract click electronic access below)
Descrição
Palavras-chave
Cão - Anestesia, Minimum alveolar concentration, Clonidine
Como citar
SISTO, Renata Kerche Alvaides. Efeitos da administração peridural de neostigmina associada ou não a clonidina sobre a concentração alveolar mínima do isoflurano em cães. 2010. 115 f. Dissertação (mestrado) - Universidade Estadual Paulista, Faculdade de Medicina de Botucatu, 2010.