Effect Of Dexmedetomidine On The Circulation During The Intubation Through Transthoracic Echocardiography

Objective:To study the effect of preoperative administration of dexmedetomidine during the intubaition on the circulation through transthoracic echocardiography.Methods:The study was performed in 60 cases of patients undergoing elective surgery which were randomly divided into three groups,with 20 patients in each group.In group D1 and D2,the patients were given 0.2μg·kg^-1or 0.4μg·kg^-1dexmedetomidine in 5 min after the patients coming into the operation room respectively.And group C was given the same volume of saline in 5 min after the patients coming into the operation room as controlgroup.Thentheheartrate（HR）,meanarterialpressure（MAP）,left ventricular end systolic volume（ESV）,left ventricular end diastolic（EDV）,left ventricular ejection fraction（EF%）,stroke volume（SV）,and cardiac output（CO）which were monitored in three times:after the patients coming into the operation room（T0）,at15 min after finished administration dexmedetomidine or saline（T1）,and after intubation（T2）,were compared among three groups.Results:Although no significant difference was found in the EDV,ESV,EF%,CO,SV,mean blood pressure and heart rate among three groups at T1,differences could be seen at T2.In group D1,HR,MAP,and CO were decreased significantly compared with group C（P<0.05）.Meanwhile,the reduction of HR,MAP,CO,SV,EDV and EF became significantly decreased but increased in ESV when using 0.4μg.kg^-11 dexmedetomidine before induction（P<0.05）.Conclusion:Administration of 0.4μg.kg^-11 dexmedetomidine could effectively decrease the sympathetic tone and cardiac load,which could protect the cardiac function and inhibit the circular wave caused by the stress response to the intubation during the induction of anesthesia.