The effects of pre-anesthetic single-dose dexmedetomidine on attenuation of stress response to endotracheal intubation

Objective To investigate the effects of pre -anesthetic single -dose dexmedetomidine on attenuation of stress response to endotracheal intubation in patients with general anesthesia. Methods Sixty ASA Ⅰ ～ Ⅱ patients aged 20～51 years scheduled for gynecologic laparoscopy procedure with general anesthesia were randomly divided into two groups. Finally 53 patients were enrolled. Twenty-eight patients were involved into group D (study group), who received intravenous infusion of dexmedetomidine 0.6 μg/kg diluted with normal saline for over 15 min before induction. Twenty-five patients were involved into group C (control group), who received the same volume of normal saline infusion. Anesthesia was induced with propofol (target -controlled infusion, with the plasma concentration of 3 μg/ml), fentanyl (3 μg/kg) and rocuronium (0.6 mg/kg). Endotracheal intubation was performed when plasma concentration of propofol reached to 3 μg/ml. Hemodynamic parameters including heart rate (HR) and mean arterial pressure (MAP) at the baseline, before induction (right after finishing infusion of dexmedetomidine or normal saline), and right after tracheal intubation were documented. Plasma concentrations of norepinephrine and epinephrine at baseline and after intubation were measured by high performance liquid chromatography. Results In the group D, hemodynamic parameters were kept stable during induction, while in the group C, both MAP and HR were significantly increased after intubation compared with baseline and before induction (P 0.05). There was no significant difference in plasma concentrations of norepinephrine and epinephrine between baseline and after intubation in group D (P 0.05). Plasma concentrations of norepinephrine and epinephrine increased significantly after endotracheal intubation in group C (P 0.05). Although plasma concentrations of norepinephrine and epinephrine between the two groups were similar at baseline (P 0.05), both of them were statistically higher after intubation in group C than those of in group D(P 0.05). Conclusion A single dose of dexmedetomidine given before induction of general anesthesia can significantly decrease stress hormone response to endotracheal intubation, keep hemodynamics stable and contribute to perioperative safety.