Effects Of Different Dosages Of Dexmedetomidine On Stress Response During Modified Electroconvulsive Therapy

Objective:This study was designed to evaluate the effect of premedication with different doses of dexmedetomidine(DEX) on the stress response and adverse reactions in patients undergoing modified electroconvulsive therapy(MECT). Methods:One hundred and sixty patients scheduled for MECT were randomly allocated to four groups by random digit table, who receive either DEX 0.2μg/kg(group D1), 0.4μg/kg(group D2), 0.6μg/kg(group D3), or saline(group C) in a total volume of 30 ml given intravenously 10 min before the induction of anesthesia. Anesthesia was induced with propofol slowly(20mg/10s), additional propofol were given in 20 mg increments if the responsiveness to verbal command had not been lost within 60 s after 1mg/kg drug administration in each group. And then intravenous succinylcholine, 0.5mg/kg, was administered. Manual ventilation was performed with face mask using 100% oxygen, and the stimulus dosage was adjusted in accordance with “age±15% method.” Mean blood pressure(MAP) and heart rate(HR) were recorded at baseline(T0), 10 min after DEX administration(T1), after anesthesia induction(T2), and at 0, 1, 3 and 5 min after the seizure ended(T3, T4, T5 and T6, respectively). The plasma levels of epinephrine(E), norepinephrine(NE) and cortisol(Cor) were determined at(T0) and(T4). Recording spontaneous breathing time, eye-opening time, Electroencephalographic duration, inhibition index of energy and probable side effects including headache, agitation and so on. Results:MAP and HR at T 1 ~T 6 in groups D2 and D3, MAP and HR at T3~T5 in group D1 were significantly lower than those in group C(P<0.05). And, the decreased range of MAP and HR were positive correlated with the load dosage of DEX. The levels of E, NE and Cor at T4 were significantly higher than those at T0 in each groups, and the increased levels is group D3< D2< D1< C. There was no difference in time from administration of succinylcholine to spontaneous respiration returned among the three DEX groups, and which were shorter than group C. With the increasing dosages of DEX, time to opening the eyes was progressive prolonged, and the incidence rate of side effects such as headache, agitation and injection pain were lower. By the way, in group D3 one patient occured severe hypotension, four patients of HR less than 50 beats/min. There was no significant difference among the groups with regard to the EEG convulsion duration and inhibition index of energy(P>0.05). Conclusion:Premedication with 0.4μg/kg DEX combined propofol infusion is more effective and safer than the loading dose of 0.2μg/kg or 0.6μg/kg DEX in MECT.