低温麻醉下安氟醚及异氟醚对心内传导系统的影响

Effects of enflurane and isoflurane on heart conduction system under hypothemia

目的 研究低温 3 0℃下安氟醚、异氟醚对心内传导系统的影响。方法 健康家兔 4 8只 ,离体 L angendorff灌注 ,随机分为六组 ( n=8) :常温 0 .65 MAC Enf组 ,常温 1.3 MAC Enf组 ,常温1.3 MAC Iso组 ,低温 0 .65 MAC Enf组 ,低温 1.3 MAC Enf组 ,低温 1.3 MAC Iso组。不同组别 K- H液平衡灌注 15分钟后测定 HR、SACT、CSNRT、SNRTI、AVERP、2∶ 1B、QTc、P- R间期、QRS时间。结果 常温 0 .65 MAC Enf对心内传导系统无影响。 1.3 MAC Enf使 SACT、CSNRT、P- R间期显著延长 ( P<0 .0 5 ) ,常温 1.3 MAC Iso使 CSNRT显著延长 ( P<0 .0 5 )。低温 0 .65 MAC Enf,1.3 MACEnf及 1.3 MAC Iso的心电生理参数值 ( SNRTI除外 )分别较常温相应麻醉强度时有显著 ( P<0 .0 5 )或非常显著 ( P<0 .0 1)的差异。结论 常温下安氟醚对窦房结自律性及房室传导功能有浓度依赖性抑制作用 ;低温显著加重安氟醚、异氟醚对心内传导系统的抑制。

Objective To investigate the effects of enflurane and isoflurane with hypothermia on isolated rabbiit hearts conduction system.Methods Fourty eight rabbit hearts were perfused by modified Krebs Hensleit buffer with Langendorff device.All of hearts were randomly divided into six groups (n=8):0.65MAC enflurane (37.5℃),1.3MAC enflurane (37.5℃),1.3MAC isoflurane (37.5℃),0.65MAC enflurane(30℃),1.3MAC enflurane(30℃),1.3MAC isoflurane (30℃).All groups were perfused for 15 min to derermine the cardiac electrophysiological parameters:HR,sinus node recovery time (SNRT) corrected sinus node recovery time (CSNRT),sinus node recovery time index (SNRTI),sinus atrial conduction time (SACT),atrial ventricular effective refractory period (AVERP),2∶1 block (2∶1B),P R interval and QRS.Results 0.65MAC enflurane produced no significant changes in all cardic electrophysiological parameters(P>0.05),while 1.3MAC enflurane lengthened SACT,CSNRT and P R interval (P<0.05)and 1.3MAC isoflurane only lengthened CSNRT(P<0.05)at 37.5℃.Compared with at 37.5℃ inhalation anesthetics made a significant changes in all eiectrophysiological paramenters except for SNRTI(P<0.05 or P<0.01)at 30℃.Conclusion Enflurane and isoflurane may cause pronounced depression on heart conduction system at a lower temperature,especially enflurane.