Effect of general anesthesia induction assisted dexmedetomidine on pressor responses to ephedrine

Objective To observe the effect of general anesthesia induction assisted dexmedetomidine on blood pressure responses to ephedrine.Methods Forty-four patients scheduled for laparoscopic cholecystectomy were randomly divided into normal saline(group N)and dexmedetomidine(group D)group.Group D was treated 15 minutes by micro pump injecting the dose of 0.8μg/kg dexmedetomidine before anesthesia induction.Then the rate was changed to 0.4μg·kg-1·h-1 and maintained.Meanwhile patients were given anesthesia induction and trachea intubation.0.1 mg/kg ephedrine was injected 5minutes after trachea intubation.Likewise group N was treated 15 minutes by micro pump injecting physiological saline before anesthesia induction.The other treatments were same.SBP,DBP and HR were recorded before micro pump injecting dexmedetomidine or physiological saline(T0),before anesthesia induction(T1),during trachea intubation(T2),2min after trachea intubation(T3),during ephedrine injection(T4),2 min,5 min,10 min and 15 min after ephedrine(T5,T6,T7,T8).Results Compared with T0,SBP and DBP of group N was lower at T1,T3-T8 but SBP,DBP and HR was higher at T2(P0.05 or P0.01).HR of group N was lower at T4,T7 and T8(P0.05 or P0.01).SBP at T1-T8,DBP at T1-T4 and T8,HR at T1 and T3,T4 was lower in group D(P0.05 or P0.01).Compared with T2,SBP,DBP and HR of group N was lower at T3 and T4(P0.01).SBP of group D was lower at T4(P0.01).Compared with T4,SBP of group N was only higher at T5 and T6(P0.05 or P0.01).SBP,DBP and HR of group D were higher at T5-T7 and SBP was kept higher until T8(P0.01).Compared with group N,HR of group D was lower at T1-T3(P0.05 or P0.01),SBP,DBP was lower at T2(P0.01)and was kept higher from T5 to T8(P0.05 or P0.01).Conclusion Intubation stress response will be relieved during anesthesia induction with dexmedetomidine,which can amplified ephedrine effect.