Effect of dexmedetomidine on minimal induced dose of propofol and endotracheal intubation cardiovascular reaction

Objective To investigate the effect of dexmedetomidine on minimal induced dose of propofol and cardiovascular responses to tracheal intubation.Methods A double-blind randomized controlled trial was conducted.Sixty patients who underwent elective laparoscopic surgery were randomly divided into the dexmedetomidine group (treatment group) and control group.Patients in treatment group were given dexmedetomidine at dose of 0.1 μg/kg · min for 10 min before anesthesia induction,and then infused with 0.4 μg/kg · h until the end.Sodium chloride injection was infused at the same rate in control group.After 10 minutes from the start of dexmedetomidine or sodium chloride injection,propofol was infused by 0.4 mg/kg · min.The dosage of propofol used was recorded when eyelash reflex disappearing,and BIS value in 40 to 60.Propofol was infusion at the same rate,and laryngoscope was incubated at 2 minutes after fentanyl and rocuronium were given.The alertness/sedation (OAA/S scores),mean arterial pressure (MAP),heart rate,pluse oxygen saturation (SpO2) and BIS values were recorded at baseline (before dexmedetomidine or sodium chloride injection infusion),5 and 10 minutes after dexmedetomidine or sodium chloride injection infusion,at the time of eyelash reflex disappearing,before endotracheal intubation,placing the laryngoscope,1,3 and 5 min after intubation.Results OAA/S scores and BIS values in the treatment group were significantly lower than that of control group at 5 minutes and 10 minutes after the dexmedetomidine or sodium chloride injection infusion(P ＜0.05).MAP in treatment group was higher than that of control group at the time of eyelash reflex disappearing,before endotracheal intubation,placing the laryngoscope,1,3 and 5 minutes after intubation (P ＜0.05).Heart rate in treatment group was lower than that of control group at 5 and 10 minutes after dexmedetomidine or sodium chloride injection infusion and before the endotracheal intubation(P ＜ 0.05).There was no significant difference in terms of SpO2 between two groups (P ＞ 0.05).When patients consciousness disappeared and BIS values were in 40-60,the minimum induced dose of propofol was (88.00 ± 25.91) mg in treatment group and (117.33 ± 25.45) mg in control group.The dosage of propofol treatment group was obviously less than control group (t =4.423,P ＜ 0.05).Conclusion Dexmedetomidine reduces the minimum induced dose of propofol while maintaining more stable hemodynamic changes during anesthesia induction.However,there has no obvious inhibition effect on cardiovascular response to tracheal intubation. Key words: Dexmedetomidine ;  Propfol ;  Bispectral index;  Laparoscope ;  Trachea cannula