ABSTRACT
Objective To investigate the effects of different doses of dexmedetomidine used in SEP and MEP monitoring in patients undergoing neurosurgery. Methods Eighty patients undergoing neurosurgery receiving SEP and MEP monitoring were randomly divided into 4 groups(n = 20 each):group C,group D1,group D2 and group D3. In groups D1 ,D2 and D3 ,dexmedetomidine 0.5 μg/kg was infused over 10 minutes before anesthesia induction,and then was infused at a rate of 0.1,0.3 and 0.5μg/(kg·h)respectively toward the end of operation. Group C received the equal volume of normal saline. HR ,MAP and BIS were recorded at admission to the operating room(T1),skin incision(T2),when the muscle relaxants were stopped(T3)and 50 minutes later(T4). The current intensity and the time when first MEP was induced after muscle relaxant was stopped ,the amplitudes and latencies of SEP(N20-P25,N20)and MEP on thenar muscle at T4,the total consumption of propofol,and development of adverse affects were also recorded. Results Compared with groups C and D1,HR and MAP were decreased at T2-T4 in groups D2 and D3(P0.05). Conclusion Dexmedetomidine infused at 0.3 μg/(kg · h) after infusion of a loading dose of 0.5 μg/kg could improve monitoring quality of MEP through reducing the amount of propofol consumed ,have less inhibition on MEP than other groups,have no obvious effects on SEP,andmaintain hemodynamic stability.
ABSTRACT
Objective To observe the feasibility and safety of dexmedetomidine used in motor evoked potentials(MEP)monitoring in patients undergoing neurosurgery.Methods Thirty ASA Ⅰ orⅡ patients,male 1 5 cases,female 1 5 cases,aged 20-60 years,weighing 40-80 kg undergoing neuro-surgery receiving MEP monitoring were randomly divided into 2 groups (n =1 5 each):control group (group C)and dexmedetomidine group (group D).In group D,dexmedetomidine 0.5 μg/kg was in-fused over 10 minutes before anesthesia induction,and then was infused at a rate of 0.5 μg·kg-1 · h-1 toward the end of operation.Group C received the equal volume of normal saline.HR,MAP and BIS were recorded at admission to the operating room (T0 ),skin incision (T1 ),when the muscle re-laxants were stopped (T2 )and 50 minutes later (T3 ).The current intensity and the time when first MEP was induced after muscle relaxant was stopped,the amplitudes and latencies of MEP on thenar muscle at T3 ,the total consumption of anesthetics,and development of adverse effects were also re-corded.Results Compared with T0 ,HR in group C at T1 ,T3 and MAP in group C at T1-T3 was in-creased,HR in group D was decreased at T2-T3 (P <0.05).Compared with group C,HR and MAP were decreased at T1-T3 in group D(P <0.05).The amount of propofol consumed and the current in-tensity inducing MEP were lower in group D than in group C (P <0.05).The amplitude of MEP at T3 was higher in group D than in group C (P <0.05).Compared with group C,the incidences of hy-pertension and tachycardia were decreased in group D,and the incidence of bradycardia was increased (P <0.05).Conclusion Dexmedetomidine used in MEP monitoring in patients undergoing neurosur-gery can meet the operation requirements,maintain hemodynamic stability,reduce the incidences of adverse reactions,and improve monitoring quality of MEP.It is a safe and feasible anesthesia method.