超声心动图在低温后复温兔左心功能评价中价值

目的探讨超声心动图评价兔低温后复温心功能的价值。方法将20只兔随机分为4组,每组各5只。第1组在室温条件下不做任何处理,为常温组;第2组置于低温环境(-23~-17℃)8 h,为低温组;第3、4组置于低温环境下8 h,并分别置于室温环境下复温2 h和4 h,分别设为复温2 h组与复温4 h组。应用超声心动图仪测量各组射血分数(EF)、舒张末期容积(EDV)、收缩末期容积(ESV)、短轴缩短率(FS)及等容舒张时间(IVRT);应用组织多普勒超声诊断技术(TDI)检测各组兔心脏在心尖四腔心切面上室间隔侧的二尖瓣环舒张早期的峰值运动速度(Em)以及收缩期的峰值运动速度(Sm)。超声测量后,从耳缘静脉取血测量肌酸激酶(CK)、肌酸激酶同工酶(CK-MB)、乳酸脱氢酶(LDH)及超敏C反应蛋白测定(h CRP)。检查、测量结束后,各组兔均处死,并每组随机取1只兔,取其左室心尖部心肌观察病理改变。结果超声心动图显示,20只兔中有1只兔为房间隔缺损,故最后纳入统计分析的动物数量为19只。对4组兔的EF、EDV、ESV、FS值分别进行两两比较发现,差异均无统计学意义(P>0.05);低温组、复温2 h组、复温4 h组的IVRT均高于常温组,差异均有统计学意义(P<0.05);复温2 h组、复温4 h组、低温组的IVRT值进行两两比较,差异均无统计学意义(P>0.05)。低温组、复温2 h组、复温4 h组的Em、Sm值均低于常温组,差异均有统计学意义(P<0.05);低温组、复温2 h组、复温4 h组的Em、Sm值两两比较,差异均无统计学意义(P>0.05)。低温组、复温2 h组、复温4 h组的CK、LDH均明显高于常温组,但4组兔的CK、CK-MB、LDH及h CRP组间两两比较,差异均无统计学意义(P>0.05)。结论超声心动图可较早的反应低温后复温对于兔左心功能的影响,可有助于临床早期诊断。

Assessment of heart function in oryctolagus cuniculus under rewarming after hypothermia by echocardiography

Objective To assess the changes of heart function under rewarming after hypothermia by echocardiography.Methods A total of 20 oryctolagus cuniculus were divided into 4 groups,with 5 in each group.The cuniculus in Group 1(room temperature group) were kept in room temperature,cuniculus in Group 2(hypothermia group) were kept in hypothermia(-23℃ to-17℃) for 8 hours without handling,cuniculus in Group 3(rewarmed 2 hours group) and Group 4(rewarmed 4 hours group) were kept in hypothermia for 8 hours then were rewarmed for 2 hours and 4 hours,respectively.Ejection fraction(EF),end-diastole volume(EDV),end-systolic volume(ESV),fractional shortening(FS) and isovolumic relaxation time(IVRT) were measured by echocardiography.Early diastolic velocity of mitral annulus(Em) and systolic velocity of mitral annulus(Sm) in interventricular septum were measured by Tissue Doppler Image(TDI).After ultrasonic measurement,blood creatine kinase(CK),creatine kinase isoenzyme(CK-MB),lactate dehydrogenase(LDH) and high sensitive C reactive protein(hCRP) were measured from the ear vein.Myocardial enzyme by bleeding from vein of ear edge was measured and myocardium of left ventricle was sent to pathology.Results One oryctolagus cuniculu with the disease of atrial septal defect was detected by echocardiography,therefore,19 oryctolagus cuniculus were included in statistical analysis.There were no statistically significant differences in EF,EDV,ESV and FS of the four groups(P>0.05);IVRT in the hypothemia group,rewarmed 2 hours group and rewarmed 4 hours group were higher than that in the room temperature group(P<0.05);there were no statistically significant difference of IVRT in the hypothermia group,rewarmed 2 hours and rewarmed 4 hours groups(P>0.05).Em and Sm value in the hypothermia group,rewarmed 2 hours and rewarmed 4 hours group were lower than that in the room temperature group(P<0.05);there were no statistically significant difference of EM and Sm value compared in the hypothermia group,rewarmed 2 hours and rewarmed 4 hours group(P>0.05).CK and LDH value were significantly higher than that in the room temperature group compared with the hypothermia group,rewarmed 2 hours and rewarmed 4 hours group,however,CK,CK-MB,LDH and hCRP,compared between each two groups had no statistically significant difference(P>0.05).Conclusion The changes of heart function in oryctolagus cuniculus under rewarming after hypothermia can be early examed by echocardiography,which is helpful for earlier clinical diagnosis.