HYPNOTIC, ANALGESIC, AND EEG ENDPOINTSDURING INTRAVENOUS ANAESTHESIA: Effective doses, catecholamine, and cardiovascular responses

In this study, differences, effective doses, and concentrations of propofol and thiopental in hypnotic, analgesic, and EEG end-point were evaluated. Nine rabbits, and 143 patients were studied. In rabbits propofol revealed to be the best choice because recovery was rapid and breathing patterns were well preserved. In humans propofol attenuated better the catecholamine response (CA) to tracheal intubation (TI) than thiopental. The CA response to TI was almost totally blocked during burst suppression pattern (BSP) of EEG induced by propofol. At BSP level thiopental attenuated the cardiovascular response to TI nearly as well as propofol. Remifentanil infusion started before propofol significantly reduced times and doses of propofol at the attainment of differrent endpoints. Remifentanil also affects the BIS value and might be kinetically useful for loss of consciousness because it accelerates the hypnotic onset of propofol. Propofol and thiopental have similarities in BSP but during propofol 13-15 Hz spindle oscillations are seen. An algorithm for automatic detection of BSP was developed.