title: Effect-site concentration of remifentanil for blunting hemodynamic responses to tracheal intubation using light wand during target controlled infusion-total intravenous anesthesia.
abstract: BACKGROUND
  Transillumination using a light wand is an alternative type of laryngoscope used for tracheal intubation. There is little information available on the effect-site concentration of remifentanil required to control hemodynamic changes induced by tracheal intubation using the transillumination method during total IV anesthesia. We therefore conducted this study to determine the effect-site concentration of remifentanil blunting hemodynamic responses after tracheal intubation in patients receiving propofol anesthesia.
  
  
  METHODS
  We enrolled 26 healthy adult patients (ASA physical status I-II), aged 16-67 scheduled for surgery within 2 hours. All patients received a target-controlled infusion of 4 µg/ml propofol. The effect-site target-concentration of remifentanil of 5.0 ng/ml was chosen for the first patient. We used the Dixon's up-and-down sequential allocation method for determining the next remifentanil concentration. The time required for tracheal intubation was measured as the level of intubation stimulation.
  
  
  RESULTS
  The average intubation time was 13.9 ± 9.1 seconds. From the Dixon's method, the EC(50) of remifentanil blunting the hemodynamic response to tracheal intubation was 2.94 ng/ml.
  
  
  CONCLUSIONS
  This study shows that effect-site concentrations of remifentanil of 2.94 ng/ml is effective in blunting sympathetic responses to tracheal intubation in 50% of patients with normal airway anatomy when combined with a target controlled infusion of propofol (4 µg/ml).
authors: Department of Anesthesiology and Pain Medicine, Sanggye Paik Hospital, College of Medicine, Inje University, Seoul, Korea.
authors: Jun Heum
authors: JH
authors: Yon
authors: Jae Keun
authors: JK
authors: Jo
authors: Young-Suk
authors: YS
authors: Kwon
authors: Hae-Gyun
authors: HG
authors: Park
authors: Sangseok
authors: S
authors: Lee