Warm Blood Cardioplegia

The current gold standard of cardiac surgical myocardial protection is the administration of cardioplegia. Administration of potassium-rich cardioplegia solution leads to elective reversible diastolic cardiac arrest and results in decreased myocardial metabolic demand. It provides intraoperative myocardial protection by matching myocardial oxygen demand during intraoperative periods of decreased oxygen supply. The goal of cardioplegia is to provide a motionless (non-beating) operative field along with the protection of myocardial function. Early cardioplegic methods used cold crystalloid solutions to induce and maintain cardiac arrest during heart surgery. Since the 1950s, cold crystalloid cardioplegia (CCC) was the cornerstone of cardiac surgical practice.

In the 1970s, blood was introduced as a medium of cardioplegia delivery because of its increased oxygen-carrying capacity, innate buffering capacity (from histidine), and superior osmotic properties. The majority of cardiac surgeons in the United States use blood cardioplegia (72%). No standard federal guidelines exist for the composition of cardioplegia solution. The optimal temperature of cardioplegia has been a matter of debate. Although hypothermia has the advantage of decreasing myocardial oxygen demand, it has been criticized for impairing the homeostatic processes of the myocardium. Normothermic or warm blood cardioplegia (WBC) provides a metabolically balanced milieu for the myocardium and helps in the resuscitation of energy-depleted myocardium. Lichtenstein et al. were the first to report the use of warm heart surgery when they administered continuous warm cardioplegia for a patient requiring a cross-clamp time of over 6 hours.