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

Abstract

Intracranial variables in propofol or ABSTRACTThe effects of subarachnoid administration of iohexol on intracranial hemodynamic in dogs anesthetized with propofol or sevoflurane were evaluated. Thirty adult animals (10.92.9kg) were distributed into two groups: PG, where propofol was used for induction (100.5mg/kg), followed by a continuous rate infusion at 0.550.15mg/kg/hour, and SG, where sevoflurane was administered for induction (2.5 MAC) and for anesthetic maintenance (1.5 MAC). A fiberoptic catheter was implanted on the right superficial cerebral cortex to monitor intracranial pressure (ICP). After 30 minutes, cerebrospinal fluid (CSF) was collected at the cisterna magna and iohexol was injected. The measurements were performed before CSF collection (TA), after the iohexol injection (T0), and at 10-minute intervals (T10 to T60). Intracranial pressure decreased at T0 in SG. Cerebral perfusion pressure at T0 was higher than at TA, T50 and T60 in PG, but in SG, the mean value at T0 was higher than the ones from T20 to T60. Mean arterial pressure at T0 was higher than at TA in PG, while in SG, the values from T20 to T60 were lower than at T0. The heart rate at T60 was lower than at T0 in PG. Cardiac output at TA was lower than at T60 in SG. The cerebrospinal fluid collection and administration of iohexol promoted decrease in intracranial pressure in sevolflurane-anesthetized dogs and increase in cerebral perfusion pressure in propofol-anesthetized dogs.Keywords: anesthesia, dogs, cerebral autoregulation, myelography Palavras-chave: cão, anestesia, autoregulação cerebral, mielografia RESUMO Avaliaram-se os efeitos da administração subaracnóidea de iohexol sobre a hemodinâmica intracraniana em cães anestesiados com propofol ou sevofluorano. Trinta e dois animais (10,9±2,9kg) foram distribuídos em dois grupos: no GP, o propofol foi usado para indução, 100.5mg/kg, seguido por infusão contínua, 0,55±0,15mg/kg/min; no GS, o sevofluorano foi administrado para indução, 2,5 CAM, e manutenção, 1,5 CAM, da anestesia. O cateter de fibra óptica foi implantado na superfície direita do córtex cerebral para monitorar a pressão intracraniana (PIC). Após 30 minutos, o fluido cerebroespinhal (FCS) foi coletado da cisterna magna e o iohexol injetado. As mensurações ocorreram antes da coleta do FCS (TA), depois da injeção de iohexol (T0) e em intervalos de 10 minutos (T10 a T60