[Experimental study on resuscitation and salvage of myocardial function (RSMF) after normothermic ischemic arrest]

We studied in anesthetized dogs, the effects of cardiopulmonary bypass with normothermic blood, crossclamping of the aortic root, and continuous warm blood cardioplegia as a part of circulatory support on the ability of the recovery of the deteriorated myocardial function, and compared this method with the circulatory support under empty beating stage. Eleven dogs were subjected to the deteriorated myocardial function by 30 minute normothermic ischemic arrest and myocardial function was measured (baseline function). In 5 dogs (Group A), coronary perfusion of 5 ml/kg/min with normothermic blood was established under empty beating state. In other 6 dogs (Group B), the aorta was then clamped and 30 minute infusion of warm blood contained 15 mEq/l of potassium and 2 mEq/l of Magnesium was given by 2.5 ml/kg/min as a part of circulatory support. After this, aortic clamp was released and coronary perfusion of 5 ml/kg/min with normal warm blood followed under empty beating state. Cardiac function was measured at the periods of 40, 60 and 90 minutes of circulatory support and compared between the two groups. The parameters of left ventricular function (developed pressure, dp/dt, -dp/dt) were deteriorated by 30 minutes ischemia by about 50% compared with baseline function. In Group a, they improved gradually along with the duration of circulatory support and 90 minutes were required to return to the baseline function. In Group B, however, their % recovery reached 100% at the period of 40 minutes and maintained over 100% thereafter. RSMF could recover myocardial function from ischemic damage more quickly and effectively compared with circulatory support under empty beating state.