Background: Systemic inflammatory response syndrome (SIRS) is a common complication after cardiac surgery. There are no definite optimal glycemic threshold for pediatric patients receiving open-heart surgery with CPB. The study aimed to investigate the optimal cardiopulmonary bypass (CPB) glucose in patients undergoing cardiac surgery.

Methods: We enrolled children with congenital heart disease who underwent surgical repair between June 2012 and December 2020. We included only patients who underwent cardiac surgery with CPB. The primary outcome was severe SIRS. A two-piece-wise regression model was applied to examine threshold effect of CPB glucose on severe SIRS.

Results: A total of 7350 patients were enrolled in the present study, of whom 3895 (52.99%) are female. After potential confounders were adjusted, non-linear relationship was detected between CPB glucose and severe SIRS, whose turning point was 8.1. By gender, the J-shaped risk curve for female patients is not significantly different from the risk curve for male patients. With CPB glucose < 8.1mmol/L, the estimated dose-response curve was consistent with a horizontal line. However, the prevalence of severe SIRS increased with increasing glucose up to the turning point (Glucose > 8.1mmol/L); the odds ratio (OR) of the Glucose was 2.13 (95% CI: 1.99-2.28).

Conclusions: The present study indicates the association of CPB glucose with inflammatory response after pediatric cardiac surgery. The patients might have the best outcomes with the optimal CPB glucose no more than 8.1mmol/L.