RESUMO
BACKGROUND: The purpose of this study is to determine the optimal dose of remifentanil and propofol for minimizing the cardiovascular changes to tracheal intubation during total intravenous anesthesia (TIVA) using propofol target controlled infusion (TCI). METHODS: One hundred thirty five patients, aged 20-60 years, were randomly divided into three groups. Anesthesia was induced with remifentanil, propofol and rocuronium 1 mg/kg for intubation. Group I received remifentanil 0.1microgram/kg/min and a propofol target concentration 4microgram/ml. Group II received remifentanil 0.2microgram/kg/min and propofol 4microgram/ml. Group III received remifentanil 0.2microgram/kg/min and propofol 3microgram/ml. Remifentanil was infused continuously, and 2 minutes after remifentanil infusion, propofol was infused continuously. Mean arterial blood pressure (MAP) and heart rate (HR) were measured at pre-induction, 1 minute after remifentanil infusion, before propofol TCI, immediately before and after intubation and 1, 2, 3 minutes after intubation, respectively. RESULTS: Compared with pre-induction values, MAP at immediately after intubation was significantly increased in group I, but decreased in group II, with no change in group III. The HR immediately after intubation was significantly increased after intubation in all groups compared to the pre-induction values, but the rate of increase of HR in groups II, III were significantly lower than those of group I (p < 0.05). Hypotension was observed in 6 patients in group II and 3 in group III. CONCLUSIONS: Remifentanil 0.2microgram/kg/min and the propofol target concentration 3microgram/ml are optimal doses for minimizing cardiovascular changes and side effects to tracheal intubation during TIVA.
