Yano Y, Braimbridge M V, Hearse D J
Cardiovascular Research, Rayne Institute, St. Thomas' Hospital, London, England.
J Thorac Cardiovasc Surg. 1987 Dec;94(6):887-96.
Myocardial protection during pediatric cardiac operations has been suggested to be less successful than in adult hearts. In the present study we have compared the resistance of adult, infant, and neonatal rat hearts to various periods of ischemic arrest with normothermic (37 degrees C) crystalloid cardioplegia. Isolated hearts with intraventricular balloons, from adult (50 to 60 days of age, heart weight 865 +/- 13 mg), infant (20 to 25 days of age, heart weight 251 +/- 3 mg), and neonatal rats (3 to 5 days of age, heart weight 40 +/- 1 mg) were subjected to 10, 20, 30, 40, 50, 60, 80, and 100 minutes of ischemia (n = 6 hearts for each time point and for each age group). St. Thomas' Hospital cardioplegic solution was infused at the onset of the period of arrest. With increasing durations of ischemia there was a declining postischemic recovery of function. Up to 40 minutes of ischemia there was no significant difference between the three age groups in postischemic recovery of left ventricular developed pressure: 40.3% +/- 4.4%, 45.4% +/- 6.5%, and 44.4% +/- 2.2% of preischemic control for adult, infant, and neonatal hearts, respectively. Beyond 40 minutes adult and infant hearts showed an identical deterioration with effectively no recovery beyond 60 minutes of ischemia. By contrast, neonatal hearts were much more resistant to ischemia. After 100 minutes of ischemia the mean recovery of left ventricular developed pressure was 20.9% +/- 1.1%, whereas in infant and adult hearts the values were 0.6% +/- 0.3% after 80 minutes of ischemia and 0% after 100 minutes, respectively. Analysis of creatine kinase leakage also indicated that with ischemic durations in excess of 40 minutes, the neonatal heart was far more resistant to ischemia, and creatine kinase leakage per gram dry weight was much less than in infant or adult rats. Analysis of the rates of recovery during reperfusion again revealed differences between neonatal hearts and hearts from the other two age groups. We conclude that in the normal rat the neonatal heart has a greater inherent tolerance to ischemia than that of the infant or adult rat.
有人认为，小儿心脏手术期间的心肌保护效果不如成人心脏手术。在本研究中，我们比较了成年、幼年和新生大鼠心脏在常温（37℃）晶体停搏液灌注下对不同时长缺血停搏的耐受性。将带有心室内球囊的成年（50至60日龄，心脏重量865±13毫克）、幼年（20至25日龄，心脏重量251±3毫克）和新生大鼠（3至5日龄，心脏重量40±1毫克）的离体心脏分别进行10、20、30、40、50、60、80和100分钟的缺血处理（每个时间点和每个年龄组n = 6颗心脏）。在停搏开始时注入圣托马斯医院停搏液。随着缺血时间延长，缺血后功能恢复逐渐下降。缺血40分钟以内，三个年龄组左心室舒张末压的缺血后恢复无显著差异：成年、幼年和新生心脏分别为缺血前对照的40.3%±4.4%、45.4%±6.5%和44.4%±2.2%。超过40分钟后，成年和幼年心脏表现出相同程度的恶化，缺血60分钟后基本无恢复。相比之下，新生心脏对缺血的耐受性要强得多。缺血100分钟后，左心室舒张末压的平均恢复率为20.9%±1.1%，而幼年和成年心脏在缺血80分钟后的恢复率分别为0.6%±0.3%和100分钟后的0%。肌酸激酶泄漏分析也表明，缺血时长超过40分钟时，新生心脏对缺血的耐受性要强得多，每克干重的肌酸激酶泄漏量远低于幼年或成年大鼠。再灌注期间恢复率分析再次显示新生心脏与其他两个年龄组的心脏存在差异。我们得出结论，在正常大鼠中，新生心脏对缺血的固有耐受性比幼年或成年大鼠更强。
