Background: Pediatric cardiac surgery is still a high-risk procedure, with mortality being a significant concern. Lactate clearance has been demonstrated to enhance outcomes in critically ill adult populations; however, data regarding its significance in the context of pediatric cardiac surgery has been limited, particularly in resource-limited settings like Nepal. The aim of this study was to evaluate lactate clearance as a predictor of mortality in children undergoing cardiac surgery with cardiopulmonary bypass (CPB).

Methods: This was a prospective observational cohort study conducted at Shahid Gangalal National Heart Center (SGNHC) involving 129 pediatric patients (?14 years) undergoing elective cardiac surgery for congenital heart disease. Lactate levels were measured at several time points: T0 (post-induction), T1 (ICU admission), and T6, T12, T18, and T24 hours postoperatively. Patients were classified into two groups based on their lactate clearance rates: high (?10%) and low (<10%).The primary outcome was in-hospital mortality; secondary outcomes included duration of mechanical ventilation, inotropic support, and ICU stay.

Results: Non-survivors (n=20) had significantly lower lactate clearance at all time points compared to survivors (n=109) (p<0.001). High lactate clearance was associated with reduced mortality (1.9% vs. 22%, p=0.03), shorter mechanical ventilation (11.29±4.73 vs. 14.56±6.73 hours, p<0.001), and shorter ICU stay (48.85±7.26 vs. 66.64±25.46 hours, p=0.004).

Conclusions: Lactate clearance is a significant prognostic marker of mortality in pediatric patients undergoing elective cardiac surgery for congenital heart defects. The ongoing monitoring of lactate clearance may facilitate the early identification of high-risk patients in the early postoperative period and guide interventions that could potentially improve postoperative outcomes.