Efeitos cardiorrespiratórios da infusão contínua de amitraz ou de romifidina em equinos anestesiados com isofluorano. Determinação das concentrações plasmáticas do amitraz
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Data
2009-03-06
Autores
Mendes, Marina Ceccato [UNESP]
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Universidade Estadual Paulista (Unesp)
Resumo
Com base na ação do amitraz (AMZ) e da romifidina (RMF) em receptores alfa-2 adrenérgicos e nas possíveis vantagens da associação destes fármacos com agentes inalatórios para uma anestesia geral segura, compararamse os efeitos clínicos, cardiocirculatórios e hemogasométricos da infusão contínua (IC) de AMZ ou de RMF associada ao isofluorano. Relacionaram-se os efeitos observados à concentração plasmática do amitraz (CPA) e investigaram-se possíveis efeitos farmacodinâmicos do diluente lipídico (DIL) utilizado na sua formulação. A medicação pré-anestésica (MPA) intravenosa (IV) para cada grupo foi: RMF - 60 μg/kg; AMZ - 0,2 mg/kg; DIL - 60 μg/kg de RMF. Induziu-se a anestesia com midazolam (0,1 mg/kg IV) e cetamina S(+) (0,2 mg/kg IV). A manutenção foi feita com 1,3 V% de isofluorano associado às ICs (RMF - 60 μg/kg.h; AMZ - 0,2 mg/kg.h; DIL - 0,1 mL/kg.h) por 60 minutos. Um minuto após a MPA a CPA média foi 396 ng/mL, aumentando durante a IC (de 93 ng/mL para 257 ng/mL) e diminuindo na recuperação, atingindo 47 ng/mL em 60 minutos. A RMF causou boa sedação e indução, com intubação fácil; manteve a FC estável e aumentou gradualmente a PAM, alterando pouco o CO2; resultou em recuperação ideal. O AMZ causou sedação leve e manteve planos anestésicos mais superficiais do que a RMF, com hipotensão durante a IC; a indução e a intubação foram de boa qualidade; o miorrelaxamento foi maior do que com RMF; a recuperação não teve boa qualidade. O DIL não causou sedação e resultou em recuperação de má qualidade, sendo inerte em relação aos efeitos do AMZ. Concluiu-se que há possibilidade do uso clínico do AMZ, ficando indicados estudos complementares.
Based on the action of amitraz (AMZ) and romifidine (RMF) on alpha-2 adrenergic receptors and in the possible advantages of combining them with inhalation anesthetics for a safe general anesthesia, the clinical, cardiocirculatory and hemogasometric effects of the continuous infusion (CI) of AMZ or RMF in association with isoflurane anesthesia were compared. The observed effects were related to the AMZ plasmatic levels (APL). The existence of pharmacodynamic effects of the lipid vehicle (LV) used for AMZ formulation was also investigated. The intravenous (IV) pre-anesthetic medications (PAM) were: RMF - 60 μg/kg; AMZ - 0.2 mg/kg; LV - 60 μg/kg de RMF. Anesthesia was inducted with midazolam (0.1 mg/kg IV) and S-ketamine (0.2 mg/kg IV) and maintained with 1.3 V% isoflurane, in association with the CIs (RMF - 60 μg/kg.h; AMZ - 0.2 mg/kg.h; LV - 0.1 mL/kg.h) for 60 minutes. One minute after PAM, APL was 396 ng/mL. During the CI, APL increased from 93 to 257 ng/mL. On recovery, APL decreased to 47 ng/mL in 60 minutes. With RMF there were good sedation and induction and the intubation was easy; HR was stable and MAP increased, with little CO2 alterations; the recovery was ideal. AMZ had less sedative effect and reached superficial anesthesia compared to RMF, with hypotension during CI; there were good induction and easy intubation; miorelaxation was greater with AMZ than with RMF; recovery was not good. The LV did not induce sedative effects and resulted in a poor recovery; it did not influence AMZ effects. The clinical use of AMZ is possible, but further studies are indicated.
Based on the action of amitraz (AMZ) and romifidine (RMF) on alpha-2 adrenergic receptors and in the possible advantages of combining them with inhalation anesthetics for a safe general anesthesia, the clinical, cardiocirculatory and hemogasometric effects of the continuous infusion (CI) of AMZ or RMF in association with isoflurane anesthesia were compared. The observed effects were related to the AMZ plasmatic levels (APL). The existence of pharmacodynamic effects of the lipid vehicle (LV) used for AMZ formulation was also investigated. The intravenous (IV) pre-anesthetic medications (PAM) were: RMF - 60 μg/kg; AMZ - 0.2 mg/kg; LV - 60 μg/kg de RMF. Anesthesia was inducted with midazolam (0.1 mg/kg IV) and S-ketamine (0.2 mg/kg IV) and maintained with 1.3 V% isoflurane, in association with the CIs (RMF - 60 μg/kg.h; AMZ - 0.2 mg/kg.h; LV - 0.1 mL/kg.h) for 60 minutes. One minute after PAM, APL was 396 ng/mL. During the CI, APL increased from 93 to 257 ng/mL. On recovery, APL decreased to 47 ng/mL in 60 minutes. With RMF there were good sedation and induction and the intubation was easy; HR was stable and MAP increased, with little CO2 alterations; the recovery was ideal. AMZ had less sedative effect and reached superficial anesthesia compared to RMF, with hypotension during CI; there were good induction and easy intubation; miorelaxation was greater with AMZ than with RMF; recovery was not good. The LV did not induce sedative effects and resulted in a poor recovery; it did not influence AMZ effects. The clinical use of AMZ is possible, but further studies are indicated.
Descrição
Palavras-chave
Anestesia veterinaria, Equino, Amitraz, Infusão contínua, Romifidina, Anesthesia, Horse, Continuous infusion, romifidine
Como citar
MENDES, Marina Ceccato. Efeitos cardiorrespiratórios da infusão contínua de amitraz ou de romifidina em equinos anestesiados com isofluorano. Determinação das concentrações plasmáticas do amitraz. 2009. xix, 118 f. Tese (doutorado) - Universidade Estadual Paulista, Faculdade de Ciências Agrárias e Veterinárias, 2009.