不同负荷剂量右美托咪定对心脏传导系统的影响

Effects of different doses of dexmedetomidine on cardiac conduction system

目的探讨单次泵注不同负荷剂量右美托咪定对心脏传导系统的影响。方法择期行骨科手术男性患者80例,年龄20~65岁,ASAⅠ或Ⅱ级,随机分为四组,每组20例。D1、D2、D3组分别采用微量泵输注右美托咪定0.3、0.5和0.8μg/kg,C组以同样方式输注等容量生理盐水,输注时间为10min。记录泵注前(T_1)、泵注后5min(T_2)、10min(T_3)、泵注结束后10min(T_4)时患者MAP、HR、SpO_2和12导联ECG,计算P波时限、P-R间期、QRS时限和QTc值。结果 T_2~T_4时D2、D3组MAP明显低于,HR明显慢于T_1时和C组(P<0.05)。T_2~T_4时D2、D3组QTc值明显短于T_1时和C组(P<0.05)。四组P波时限、P-R间期和QRS时限组间组内差异无统计学意义。结论右美托咪定不影响心脏传导系统,0.5及0.8μg/kg负荷剂量右美托咪定可有效缩短QT间期,但可能对基础心率偏慢患者宜选用不超过0.5μg/kg负荷剂量右美托咪定,避免严重心动过缓。

Objective To investigate the effect of dexmedetomidine on cardiac conduction system at different loading doses.Methods Eighty male patients with orthopedic surgery,aged 20-65 years,falling into ASA physical atatusⅠ orⅡ,were randomly divided into groups D1,D2,D3 and C with 20 in each.Groups D1,D2 and D3 were infused with dexmedetomidine 0.3,0.5 and 0.8μg/kg using a micro-pump for 10 min,group C infused 0.9% NaCl solution in the same manner.MAP,HR,SpO_2 were recorded and ECG was traced before injection（T_1）,5 min（T_2）,10 min（T_3）after injection and 10 min after the end of pumping（T_4）.P wave duration,P-R interval,QRS time,and QTc value were calculated.Results There was no significant difference in SpO_2,P wave duration,PR interval and QRS time among the four groups.There was no significant difference in MAP,HR and QTc value in group C and group D1.Compared with that in group C,MAP was significantly decreased,HR was significantly slowed down and QTc value was significantly shortened in group D2 and D3 from T2 to T4（P〈0.05）.Conclusion Dexmedetomidine does not affect the cardiac conduction system.0.5μg/kg and 0.8μg/kg dexmedetomidine can effectively shorten the QT interval.To avoid severe bradycardia,patients with low heart rate should use no more than 0.5μg/kg dexmedetomidine.