Cold Intermittent Cardioplegia Reduces the Acidosis During Prolonged Cardiac Surgery with Cardiopulmonary Bypass

The effect on acid-base balance efficacy of intermittent warm and cold blood cardioplegia (IWBC, ICBC) was assessed in 44 patients who underwent cardiac surgery with prolonged aortic cross clamping. With this purpose a customized multi sensor probe was inserted in the coronary sinus, and pH, PO2, PCO2 and temperature were continuously measured at 1 Hz sampling rate. The mean cross-clamping time was of 76 +/- 26 min on 19 IWBC cases and of 80 +/- 24 min on 14 ICBC cases. With IWBC perfusion, at the end of every ischemic period, the lowest pH and PO2 progressively decreased and the maximal PCO2 increased. During ICBC the minimum of pH and PO2 and maximum of PCO2 at the end of different ischemic period during time were constant, also during long cross-clamping time. With IWBC, myocardial ischemia seemed not completely reversed by standardized reperfusions, as reflected by steady deterioration of PCO2 and pH after each reperfusion.