The myocardial protective effects of a moderate-potassium blood cardioplegia in pediatric cardiac surgery: a randomized controlled trial

Background: We investigated the myocardial protective effect of a moderate-potassium cold blood cardioplegic solution (K+, 10 mmol/L) in pediatric cardiac surgery.

Methods: Sixty-eight pediatric patients with congenital heart disease and undergoing open heart surgery with cardiopulmonary bypass were randomly allocated to the high potassium (HP [K+, 20 mmol/L, n=31]) cold blood cardioplegia group or the moderate potassium (MP [K+, 10 mmol/L, n=37]) cold blood cardioplegia group. Heart arresting time, rhythm recovery time, mechanical ventilation time, inotropic drug use in the intensive care unit, perioperative serum cardiac troponin I concentrations, morbidities, and mortalities were compared between the two groups.

Results: There were no differences in cardiopulmonary bypass time, aorta cross-clamping time, cardioplegia volume, lowest body temperature during cardiopulmonary bypass, total volume of cardioplegia delivered, hematocrit value, and fluid output during the operation between the two groups. However, there was a longer arresting time and a shorter rhythm recovery time in the MP group (35.6±2.4 s, and 30.8±3.1 s) when compared with that in the HP group (24.7±2.7 s, and 42.0±4.0 s, both p<0.05). The total mediastinal drainage volume, the length of stay in the intensive care unit, the postoperative inotropic drug use, and the postoperative hospital time were similar between the two groups, but the number of patients with a long postoperative mechanical ventilation time (>24 hours) in the MP group (6 of 36) was less than that in HP group (13 of 30; p<0.05). At 1 hour, 3 hours, and 6 hours after myocardium reperfusion, the serum concentration of cardiac troponin I significantly decreased in the MP group (in ng/mL: 15.18±3.57, 24.83±4.91, and 19.62±3.93, respectively) when compared with that in the HP group (in ng/mL: 32.67±5.31, 39.26±7.43, and 30.52±5.17, respectively, p<0.05).

Conclusions: The present study demonstrated that the M (10 mmol/L) cold blood cardioplegia formula is associated with better myocardial protective effects when compared with conventional HP cardioplegia in pediatric patients.