Comparison of Hemodynamic Responses Associated with Tracheal Intubation Under Various Induction Doses of Remifentanil and Propofol

.Background: The optimal dose of propofol and remifentanil induction to minimize the cardiovascular response associated with tracheal intubation may exist. We investigated the cardiovascular response associated with tracheal intubation when various continuous induction doses of remifentanil in combination with propofol were used. Methods: Seventy- five patients were randomly allocated into 1 of 3 groups: the R-0.4 P-1 group (remifentanil 0.4 μg/kg/min and propofol 1 mg/kg); the R-0.5 P-1 group (remifentanil 0.5 μg/kg/min and propofol 1 mg/kg); and the R-0.4 P-2 group (remifentanil 0.4 μg/kg/min and propofol 2 mg/kg). One minute after remifentanil infusion commenced, a bolus of propofol was injected. Rocuronium 1 mg/kg was administered 1 min after propofol injection following loss of consciousness. Controlled ventilation was then performed for 2 min, and the trachea was intubated 4 min after the start of the remifentanil infusion. The infusion rate of remifentanil was decreased to 0.1 μg/kg/min after intubation. Blood pressure (BP) and heart rate (HR) were measured during this period until 5 min after tracheal intubation. Results: The changes in BP response due to tracheal intubation in the R-0.4 P-1 group were greater than those in the other 2 groups, whereas the HR responses to tracheal intubation were similar among the 3 groups. Conclusion: The combination of remifentanil 0.4 μg/kg/min and propofol 1 mg/kg led to an exaggerated cardiovascular response to tracheal intubation compared with the other combination groups.