The effect of cardioplegic solution-induced sodium concentration fluctuation on postoperative seizure in pediatric cardiac patients

Background: Despite potential benefits of histidine-tryptophan-ketoglutarate (HTK) solution as a cardioplegic solution, it can cause hyponatremia, especially in pediatric patients. Fluctuations in the sodium concentration during cardiopulmonary bypass (CPB) can adversely affect the central nervous system. We evaluated the relationship between the cardioplegic solution, the fluctuation of sodium concentration, and the incidence of postoperative seizure in pediatric cardiac patients.

Methods: The medical records of 628 patients were reviewed for the occurrence of a postoperative seizure, type of cardioplegic solution (HTK or del Nido solution), and intraoperative data. A change of sodium concentration exceeding 15 mmol/L (ΔNa>15) during CPB was defined as a significant fluctuation of sodium concentration.

Results: Postoperative seizures were detected in 18 patients (2.9%). The ΔNa>15 was detected in 63 of 189 patients (33.3%) who received the HTK solution and in 14 of 439 patients (3.2%) who received the del Nido solution (p<0.001). The incidence of ΔNa>15 was strongly associated with postoperative seizure (odds ratio, 6.3; 95% confidence interval, 2.4 to 16.4, p=0.001). After adjusting for potential confounders, the ΔNa>15 remained significantly associated with postoperative seizure (odds ratio, 3.9; 95% confidence interval, 1.3 to 12.3, p=0.018).

Conclusions: Histidine-tryptophan-ketoglutarate solution during CPB frequently causes fluctuations of sodium concentration, usually combined with hyponatremia, which is associated with postoperative seizure. Special attention to sodium concentration is required, particularly when HTK solution is used in pediatric cardiac patients.