ENHANCED MYOCARDIAL PROTECTION DURING ISCHEMIC ARREST - OXYGENATION OF A CRYSTALLOID CARDIOPLEGIC SOLUTION

  • 1 January 1983
    • journal article
    • research article
    • Vol. 85  (5) , 769-780
Abstract
To determine if, during elective cardiac arrest, the myocardial protection afforded by a cold (4.degree. C) crystalloid K cardioplegic solution could be improved by oxygenation of the solution, 16 dogs were placed on cardiopulmonary bypass and their hearts were subjected to 4 h of cold cardioplegic arrest. Group 1 hearts (n = 8) received aerated crystalloid solution perfused through the aortic root every 20 min. Group 2 hearts (n = 8) were treated identically except that the crystalloid cardioplegic solution was fully oxygenated. Left ventricular function curves (ejecting heart) were generated before arrest (control) and after 45 min of reperfusion. A cardiac output of 1000 ml/min could be attained in only 2 hearts of group 1 after reperfusion; all but 1 heart of group 2 had excellent functional preservation. Mean postreperfusion ATP levels in group 1 and group 2 hearts were 62 and 89% of control, respectively (P < 0.01). Myocardial water content had increased significantly (P < 0.002) after reperfusion in group 1, but not in group 2. During cardioplegic solution infusion, myocardial O2 consumption (M.ovrhdot.VO2) was 1.42 .+-. 0.15 ml O2/min per 100 g LV for group 1 and 6.91 .+-. 1.27 ml O2/min per 100 g LV for group 2 (P < 0.001). O2 consumed per minute of arrest was 0.027 .+-. 0.003 ml O2/min per 100 g LV for group 1 and 0.128 .+-. 0.015 ml O2/min per 100 g LV for group 2 (P < 0.001). Postreperfusion ultrastructural evaluation of 2 of the group 1 hearts revealed severe ischemic damage in contrast to the normal ultrastructural appearance of 2 of the group 2 hearts. With careful attention given to maintenance of myocardial hypothermia and cardioplegic delivery methods, the myocardial protection afforded by an oxygenated crystalloid cardioplegic solution exceeds that provided by the aerated control and compares favorably with other methods of myocardial protection during ischemic arrest.

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