Efeitos da infusão contínua de propofol ou etomidato sobre variáveis intracranianas em cães

Abstract

Aluna de pós-graduação -FCAV-UNESP -Jaboticabal, SP 4 Escola de Medicina Veterinária e Zootecnia -UFTO -Palmas, TO 5 Curso de Medicina Veterinária -FMVA-UNESP -Araçatuba, SP  RESUMO Avaliaram-se os efeitos da infusão contínua de propofol ou de etomidato sobre as variáveis intracranianas em cães nomocapneicos. Foram utilizados 20 cães adultos distribuídos aleatoriamente em dois grupos: grupo propofol (GP) e grupo etomidato (GE). Para o GP, os animais foram induzidos à anestesia com propofol (10mg/kg) e, ato contínuo, iniciaram-se a infusão do fármaco (0,6mg/kg/min) e a ventilação controlada. No GE, o etomidato foi usado para indução (5mg/kg) e manutenção empregando-se a dose de 0,5mg/kg/min nos 10 minutos iniciais e, em seguida, de 0,2mg/kg/min. Após 30 minutos da implantação do cateter de fibra óptica do monitor de pressão intracraniana (PIC) na superfície do córtex cerebral direito, realizaram-se as primeiras mensurações (M1) da PIC, da pressão de perfusão cerebral (PPC), da temperatura intracraniana (TIC), de temperatura corpórea (TC), da pressão arterial média (PAM) e da frequência cardíaca (FC). As demais mensurações ocorreram em intervalos de 20 minutos (M2, M3 e M4). O propofol e o etomidato não ocasionaram alterações significativas nas variáveis estudadas com exceção da TC e TIC. Concluiu-se que a infusão contínua desses fármacos em cães mantém a perfusão cerebral e a autorregulação cerebral. Cães anestesiados com etomidato apresentam efeitos adversos intensos e redução gradativa da temperatura corpórea e intracraniana.Palavras-chave: cão, anestesia, etomidato, pressão intracranina, propofol ABSTRACT The effects of total intravenous infusion of propofol or etomidate on intracranial variables in normocapneic dogs were evaluated. Twenty adult mongrel dogs were randomly allotted to: propofol group (GP) or etomidate group (GE). In GP animals, the propofol was used for induction (10mg/kg), followed by immediate continuous infusion of the drug (0.6mg/kg/min) and controlled ventilation. In GE dogs, the etomidate was used for induction (5mg/kg), followed by a continuous rate infusion (CRI) at

Bispectral index in dogs with high intracranial pressure, anesthetized with propofol and submitted to two levels of FiO2

“…The stability of ICP during the continuous infusion of propofol was also observed by Paula et al (2010), who concluded that propofol administration does not change ICP and maintains the cerebral perfusion and autoregulation. Moreover, Mckeage and Perry (2003) mentioned that in normovolemic patients with stable hemodynamic states, propofol conserves or decreases ICP, while maintaining CPP.…”

“…However, there is no consideration about which is the best inspired oxygen fraction to use in these cases. In this study, FiO 2 of 1.0 was chosen because 100% of the oxygen has often been used during the anesthesia procedure (Leite, 2003;Paula et al, 2010). However, Nunes et al (2008), in a study with dogs submitted to CRI of propofol (0.7mg.kg -1 .minute -1 ) and maintained in spontaneous breathing with different FiO 2 (1.0, 0.8, 0.6, 0.4 and 0.21), concluded that 60% of the oxygen should be used.…”

Two levels of the inspired oxygen fraction in propofol-anesthetized dogs with high intracranial pressure: cardiopulmonary function

“…Besides, for the initial stage of traumatic brain injury, 100% oxygen has been indicated (Falcão et al, 2006). In this study, FiO 2 of 1.0 was chosen because the 100% oxygen has been used often during anesthesia procedure (Nunes et al, 2011;Paula et al, 2010). However, in dogs anesthetized with propofol (0.7mgkg -1 minute -1 ) and maintained in spontaneous breathing with different FiO 2 (1.0, 0.8, 0.6, 0.4 and 0.21), authors concluded that 60% of oxygen should be used (Nunes et al, 2008).…”

Intracranial variables in propofol or sevoflurane-anesthestized dogs subjected to subarachnoid administration of iohexol

“…According to Plochl et al (1999), ICP values up to 15mmHg are normal for dogs. In SG, the ICP means were within the normal values during the whole experiment.…”

“…Propofol does not seem to impair cerebral autoregulation (Omoigui, 1998;Paula et al, 2010), even though it can reduce cerebral blood flow (CBF) (Omoigui, 1998), cerebral oxygen consumption (Ravussin et al, 1988) and intracranial pressure (ICP) (Bazin, 1997;Paula et al, 2010). The ICP reduction is associated with an increase in cerebral vascular resistance, which allows the maintenance of perfusion pressure (Magella and Cheibub, 1990).…”