BACKGROUND: This study evaluated the tracheal intubating conditions and hemodynamic changes in tracheal intubation according to the different effect-site concentrations of remifentanil combined with a target controlled infusion (TCI) of propofol using low dose rocuronium.

METHODS: Forty-five patients presenting for ambulatory surgery were randomly assigned to one of three groups according to the target effect-site concentration of remifentanil: 2.5 ng/ml (group R2.5), 3.0 ng/ml (group R3.0), 3.5 ng/ml (group R3.5). After midazolam administration, anesthesia was induced using a target effect-site controlled infusion of propofol 4.0µg/ml, which was then reduced to 2.5µg/ml. At the same time, a TCI of remifentanil was started. A neuromuscular blockade was produced by rocuronium 0.4 mg/kg. The trachea was intubated 4 min after induction. The tracheal intubation conditions were assessed using a standard scoring system. The noninvasive arterial blood pressure, heart rate (HR), and bispectral index were recorded at 1 min intervals from the start of induction to 5 min after intubation.

RESULTS: Intubation was successful in all patients except for one in the R2.5 group. The number of excellent intubating conditions was significantly higher in the R3.5 group (12/15) than in the R2.5 group (6/15) (P < 0.05). The mean arterial pressure (MAP) in the R2.5 and R3.0 groups increased significantly at 1 min after intubation (P < 0.05), but the MAP in the R3.5 group increased slightly at 1 min after intubation.

CONCLUSIONS: The effect-site concentration of remifentanil 3.5 ng/ml combined with a TCI of propofol using rocuronium 0.4 mg/kg provides the most adequate intubating conditions and hemodynamic stability.