The inhibitory effects, according to infusion rate of remifentanil, on the hemodynamic responses during laryngeal microscopic surgery

Abstract

Background: The hemodynamic responses to tracheal intubation and placement of a suspension rigid laryngoscope are increases of the heart rate and blood pressure during laryngeal microscopic surgery (LMS). Therefore, several methods have been used to attenuate these responses. The aim of the present study was to compare the effects of three different infusion rate of remifentanil on the hemodynamic responses and recovery characteristics of patients who are under going LMS. Methods: Forty-five patients (ASA class 1 and 2) who were scheduled for LMS were randomly allocated to three groups. The patients received propofol 3μg/ml (the effective target concentration) with remifentanil 0.2μg/kg/min (Group R0.2), 0.3μg/ kg/min (Group R0.3), or 0.4μg/kg/min (Group R0.4), respectively. The patients` systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP), and heart rate (HR) were measured at baseline, 1 minute before and after tracheal intubation and 1 minute after placement of a suspension rigid laryngoscope. The patients` recovery characteristics (spontaneous respiration and eye opening) were assessed at 15 to 30 seconds intervals after discontinuation of the anesthetics. Results: The blood pressure and heart rate at the time of tracheal intubation and placement of the suspension rigid laryngoscope were unchanged in Group R0.3, yet they were increased in Group R0.2 and they were decreased in Group R0.4. The emergence time was significantly shorter for the R0.2 and R0.3 Groups than that for Group R0.4. Conclusions: We concluded that TIVA with using propofol and remifentanil (0.3μg/kg/min) can provide a stable hemodynamic status during LMS.