This study investigates the relationship between serum sodium trajectory and 30-day mortality in septic patients following cardiopulmonary bypass (CPB) surgery using data from the MIMIC-IV database. Among 1,038 patients analyzed, serum sodium trajectories were categorized into three groups using a group-based trajectory model (GBTM). Trajectories showed an initial decrease followed by an increase, with higher sodium levels linked to elevated mortality risk. Kaplan-Meier survival curves revealed significant differences between trajectory groups, especially between the lowest and intermediate classes (log-rank p = 0.039). Cox regression analysis confirmed that higher sodium trajectory groups were associated with increased 30-day mortality risk after adjusting for covariates.
Results indicate that elevated sodium fluctuations, even within normal ranges, may contribute to poorer outcomes. The physiological mechanisms linking sodium changes to mortality likely involve osmotic imbalances affecting cellular functions, particularly in the context of CPB-induced hemodilution. Findings emphasize the importance of rigorous monitoring and management of serum sodium levels to mitigate risks in this patient population. Future studies should explore long-term outcomes and refine strategies for serum sodium management in critically ill surgical patients.
