What is an Optimal Effect Site Concentration of Remifentanil for Minimizing the Hemodynamic Change to Endotracheal Intubation using Light Wand?

Background:In the previous studies, remifentanil reduces the hemodynamic change induced by endotracheal intubation.We studied the optimal effect site concentration of remifentanil for endotracheal intubation using light wand. Methods:Sixty ASA 1 or 2 patients scheduled for elective surgery under general anesthesia were classified in three groups according to the TCI (target controlled infusion) dose of remifentanil.Each group was administered 4μg/ml of propofol TCI, rocuronium, with 2 ng/ml (group 1), 4 ng/ml (group 2), 6 ng/ml (group 3) of remifentanil TCI.Blood pressure, heart rate and bispectral index score were measured before induction, 3 minutes after remifentanil and propofol TCI, after endotracheal intubation using light wand, and 3 minutes after endotracheal intubation.Statistical analysis was done for comparison of time and dose dependant change among the groups.Results: After endotrachal intubation, blood pressure and heart rate were significantly increased in group 1, and decreased in group 2 and 3. 3 minute after endotracheal intubation, heart rate significantly decreased in group 3, but there were no changes in group 2.Conclusions: The spontaneous BRS was decreased during ketamine induction of general anesthesia.These results suggest that anesthesia induction with ketamine impairs baroreflex control of heart rate, which may provoke hemodynamic instability.(Korean J Anesthesiol 2007; 52: 278∼83)