米伐西醇对家兔心肺复苏后心功能影响的实验研究

Effects of selective α2-adrenergic receptor agonist on postresuscitation cardiac function：experiment with rabbits

目的 明确选择性α2-肾上腺素能受体激动剂米伐西醇对心肺复苏（CPR）后血流动力学和B型利钠肽（BNP）及肌钙蛋白T（cTnT）的影响,寻求防治复苏后心功能不全的有效方法.方法 18只清洁级家兔随机均分为三组,A组：生理盐水空白对照组;B组：米伐西醇组（50 μg/kg）;C组：肾上腺素组（30 μg/kg）.建立家兔心肺复苏模型,胸外按压1 min后经右房导管分别注入上述药物.按压5min后行电除颤.持续监测血流动力学指标及左室内压变化至自主循环恢复（ROSC）后240min.分别于基础,ROSC后30、60、120、180、240min时间点检测血BNP、cTnT含量.结果 ①复苏后,B组左室舒张末压（LVEDP）显著低于A组（P〈0.05）、C组（P〈0.01）,左室内压上升和下降最大速率（peak±dp/dt）,各时间段值明显高于A组（P〈0.05）、C组（P 〈0.01）;②复苏后,B组BNP、cTnT浓度明显低于A组（P〈0.05）、C组（P〈0.01）.结论 米伐西醇可改善室颤复苏后家兔血流动力学指标,降低BNP、cTnT的浓度,对复苏后心脏有保护作用.

Objective To investigate the effects of mivazerol, a selective α2-adrenergic receptor agonist, on hemodynamics and B-type natriuretic peptide（BNP）and cardiac troponin T（cTnT） after cardiopulmonary resuscitation （CPR） so as to explore the effective method to improve postresuscitation myocardial dysfunction. Methods Cardiopulmonary resuscitation models were established in 18 rabbits. Cardiac arrest was electrically induced and left untreated for 5 min. Then the rabbits underwent extrathoracic cardiac massage and were randomly divided into 3 equal groups： blank control group undergoing infusion of normal saline （NS） during resuscitation, mivazerol group undergoing infusion of mivazero 150 μg/kg , and adrenalin grouop undergoing infusion of epinephrine （30 μg/kg）. Left ventricular end-diastolic pressure（LVEDP）, and maximum change rate of left ventricular pressure rise and fall （ peak＋dp/dt） were measured. BNP and cTnT levels were examined 15, 30, 60, 120, and 240 min after the return of spontaneous circulation （ROSC） .Four hours after ROSC the rabbits were killed. Results There were not significant differences in the baseline hemodynamic parameters among these 3 groups （all P〉0.05）. The peak ＋ dp/dt and peak-dp/dt values of these 3 groups all markedly decreased after resuscitation, the peak＋dp/dt value of the mivazerol group reaehed its lowest value [（5594± 179） mmHg], 70.0% that of the baseline value, 180 min later, and the peak＋dp/dt values at different time points of the mivazerol group were all significantly higher than those of the NS group （all P〈0.05） and the adrenalin group （all P〈0.01）. The LVEDP value of the mivazerol group increased after the appearance of ventrical fibrillation and reached the peak 30 rain later, being 262% as high as the baseline value, and then gradually decreased; the value 240 rain later was 181% as high as that of the baseline value. The LVEDP values at any time point were all significantly lower than those of the adrenalin group （all P〈0.01） and the NS group （all P〈0.05）. The BNP levels at different time points after ROSC of the mivazerol group were all significantly lower than those of the NS and adrenalin groups （P〈0.05, P〈0.01）. The cTnT levels after ROSC of the 3 groups all increased, those of the adrenalin group were all significantly higher than those of the NS and mivazerol groups （all P〈0.05）; and the cTnT levels at different time points were all significantly lower than those of the NS group （all P〈0.05）. Conclusion Selective ot2-adrenergic receptor agonist mivazerol can improve postresuscitation hemodynamics, reduces the concentrations of BNP and cTnT, thus protecting the postresuscitation myocardium.