Hemodynamic Responses according to Different Effect Site Concentration of Remifentanil during Endotracheal Intubation

Abstract

Background: We evaluated the hemodynamic responses to laryngoscopy and tracheal intubation using a different effect site concentration of remifentanil when propofol was maintained at the effect site concentration of 5.4mug/ml. Methods: Sixty patients presenting for elective surgery were randomly assigned to one of three groups according to target effect site concentration of remifentanil. Anesthesia was induced using a target effect site controlled infusion of propofol at a concentration of 5.4mug/ml. In all patients, remifentanil target controlled infusion (TCI) was started at the same time with a target effect site concentration of 0 (control group), 2 (group R2), or 4 ng/ml (group R4). Neuromuscular blockade was provided with rocuronium 0.6 mg/kg. The trachea was intubated under direct laryngoscopy 5 min after induction. Noninvasive arterial blood pressure and heart rate (HR) were recorded at 1 min interval from before induction of anesthesia until 3 min after intubation. Results: Mean arterial pressure (MAP) and HR in the control group significantly increased at 1 min after intubation (P< 0.05). MAP in group R2 and R4 significantly decreased from 2 min after induction (P<0.05), but MAP in R4 group remained significantly decreased throughout 3 min after intubation, and were lower than the control group (P <0.05). Conclusions: Effect site concentration of remifentanil at 2 ng/ml administered with propofol TCI at level of 5.4mug/ml attenuates the pressor response to endotracheal intubation, but effect site concentration of remifentanil at 4 ng/ml causes a significant hemodynamic compromise.