Fishman N H, Abouav J
Isr J Med Sci. 1981 Jan;17(1):3-7.
Cold potassium solution (4 C) is used to induce cardioplegia during coronary artery bypass surgery. When 1,000 ml of the cold solution are introduced through the root of the aorta, the temperature of the myocardium drops to about 7 C within a few minutes. At this level of hypothermia, ischemia can be tolerated for at least 2 h, the surgical field is rendered quiet and dry, and the safety and precision of the procedure are increased. This method, however, does not provide uniform cooling of the myocardium and some areas remain less protected than others. The temperatures in the different areas of the myocardium are measured directly with needle thermistors and the "warm" areas are cooled in turn, in descending order of myocardial temperature. Saphenous vein grafts are anastomosed to the arteries in these warm areas and additional cold solution is instilled through the graft until the temperature drops to 7 C. The coronary artery bypass, and any other required surgical procedure, is then performed. To maintain hypothermia, small amounts of cold solution are infused at intervals through the root of the aorta and through the appropriate graft. With this method of cooling, the operative mortality rate in a series of 200 high-risk patients with coronary artery disease in whom there was at least one factor predisposing to perioperative mortality and/or infarction was only 3%.
在冠状动脉搭桥手术中，冷钾溶液（4℃）用于诱导心脏停搏。当通过主动脉根部注入1000毫升冷溶液时，心肌温度在几分钟内降至约7℃。在这种低温水平下，缺血至少可耐受2小时，手术视野变得安静且干燥，手术的安全性和精确性得以提高。然而，这种方法并不能使心肌均匀降温，一些区域受到的保护比其他区域少。用针状热敏电阻直接测量心肌不同区域的温度，按心肌温度从高到低的顺序依次冷却“温暖”区域。在这些温暖区域将大隐静脉移植物与动脉进行吻合，并通过移植物滴注额外的冷溶液，直到温度降至7℃。然后进行冠状动脉搭桥以及任何其他所需的外科手术。为维持低温，每隔一段时间通过主动脉根部和合适的移植物注入少量冷溶液。采用这种降温方法，在一系列200例患有冠状动脉疾病的高危患者中，这些患者至少有一个导致围手术期死亡和/或梗死的因素，手术死亡率仅为3%。
