The influence of pre-injection with dexmedetomidine on sedation and tracheal intubation responses ingeneral anesthesia

Objective To observe the influence of pre-injection of dexmedetomidine on sedation and tracheal intubation responses in patients with general anesthesia.Methods Forty-two ASAⅠorⅡpatients,aged 18-60yr,with body mass index of 18-30kg /m~2,scheduled for elective subtotal thyroidectomy under total intravenous anesthesia were randomly divided into two groups: dexmedetomidine group(group D) and control group(group C).Dexmedetomidine 0.6 μg /kg was infused intravenously 15min prior to anesthesia induction in group D(with in 10 min),while equal volume of normal saline was infused in group C.All the patients received the same anesthesia induction protocol.Tracheal intubation was performed when the BIS value≤45.MAP,HR,SpO_2,BIS and Ramsay scores were monitored and recorded at the time points of pre-administration(T_0),administration completed immediately(T_1),5minutes after administration(T_2),immediately pre-intubation(T_3),immediately after successful intubation(T_4),1min(T_5),3min(T_6) and 5 min after intubation(T_7).The time when the patients losing consciousness and BIS value dropping to 45was also recorded.Results Compared with group C,the time when the patients losing consciousness and BIS value dropping to 45 was shorter in group D(P0.05).Compared with T_0,values of MAP,HR and BIS were significantly decreased,while Ramsay scores were significantly increased at T_1-T_7 in group D(P 0.05).Compared with T_0,values of MAP and BIS were significantly decreased,while Ramsay scores were significantly increased at T_3-T_7 in group C(P0.05);HR was significantly decreased at T_3,T_6 and T_7 in goup C(P0.05).Compared with T_3,MAP was significantly decreased at T_6 in group D,Values of MAP,HR were significantly increased at T_4 and T_5 in group C(P0.05).Conclusion Dexmedetomidine 0.6 μg /kg prior to induction can present obvious sedation,significantly shorten the time of induction,suppress cardiovascular responses during tracheal intubation in total intravenous general anesthesia.