Influence of heart surgery on magnesium concentrations in pediatric patients.

Background: There have been only a few investigations into the effects of cardiopulmonary bypass (CPB) on the magnesium (Mg) concentrations in pediatric patients. The purpose of the present study was to compare the postoperative Mg concentrations and their recovery time to pre-surgical values in pediatric patients undergoing CPB for surgical repair of congenital heart disease. The incidence of dysrhythmia was also determined.

Methods: Twenty-seven pediatric patients undergoing open-heart surgery with CPB were enrolled in this study. Controls were 23 pediatric patients undergoing palliative surgery without CPB. Serum Mg (SMg) concentrations and ionized Mg (iMg) concentrations were measured at four sample points: 24 h before the surgery, immediately after the surgery, 24 h after the surgery and 48 h after the surgery.

Results: Serum Mg and iMg concentrations were significantly decreased after open-heart surgery. Immediately after the surgery, the mean SMg concentration was 64.1% and the mean iMg concentration was 68.8% of the pre-surgical values. The concentration of iMg showed quicker recovery than that of SMg, and returned to normal range 48 h after surgery. However, SMg and iMg concentrations after palliative surgery did not show significant differences from the pre-surgical values. The incidence of dysrhythmia was almost the same between the two groups; dysrhythmia was observed in two patients in the open-heart surgery group and in three patients in the palliative surgery group.

Conclusions: Mg concentrations showed significant decrease after CPB; however, they showed quick recovery and did not increase the incidence of dysrhythmia in pediatric patients.