Effect of dexmedetomidine on cardiovascular response to bronchial intubation of double lumen tube in elderly patients

Objective To explore the effect of dexmedetomidine on cardiovascular response to intubation of double lumen tube in elderly patients with lung cancer.Methods 60 patients aged 65-80 years,weighing 45-75 kg,ASA Ⅰ or Ⅱ,scheduled for elective thoracic surgery were randomly assigned into dexmedetomidine group (group D,n=30) and controlled group (group C,n=30).In group D,dexmedetomidine 1 μ g/kg was infused by syringe pump for 15 min while equal volume of normal saline was given in group C before induction.Anesthesia was induced with fentanyl 4 μ g/kg,etomidate 0.3 mg/kg and atracuruim 0.15 mg/kg.After bronchial intubation was performed,the patients were mechanically ventilated.Systolic and diastolic arterial pressure (SAP,DAP),mean arterial pressure (MAP) and heart rate (HR) were recorded before infusion (T0),ending of infusing dexmedetomidine or normal saline (T1),before bronchial intubation (T2),instance of bronchial intubation (T3),1min,3min and 5min after bronchial intubation (T4-6).Results There was no significant difference of SAP,DAP,MAP and HR at T0 between the two groups (P ＞ 0.05).Compared with group C,SAP,DAP,MAP and HR at T1 and T2 in group D were significantly increased.HR at T1 in group D was obviously lower than that of group C (P ＜ 0.05).At T3-6,SAP,DAP,MAP and HR in group D were significantly lower than those in group C (P ＜ 0.05).Conclusion Intravenous infusing dexmedetomidine before induction of general anesthesia can effectively inhibit the cardiovascular response caused by bronchial intubation in elderly patients with lung cancer and maintain the stability of hemodynamics. Key words: Dexmedetomidine;  Elderly;  Bronchial intubation;  Cardiovascular response