Serum total carbon dioxide as a prognostic factor for 28-day mortality in patients with sepsis

Metabolic acidosis is commonly associated with the disease severity in patients with sepsis or septic shock. This study was performed to investigate the association between serum total carbon dioxide (TCO₂₎ concentration and 28-day mortality in patients with sepsis.

This study was a multicenter retrospective cohort study of patients with sepsis or septic shock. The relationships between serum TCO₂ and 28-day mortality, bicarbonate, pH, lactate, and anion gap were determined with cubic spline curves. The patients were divided into four groups according to their serum TCO₂ concentration: Group I (TCO₂ > 20 mmol/l), Group II (15 < TCO₂ ≤ 20 mg/dl), Group III (10 < TCO₂ ≤ 15 mmol/l), and Group IV (TCO₂ ≤ 10 mmol/l).

A total of 3168 patients were included in the analysis, and the overall mortality rate was 24.1%. Serum TCO₂ concentrations below 20 mmol/l showed an almost linear correlation with mortality as well as with lactate, bicarbonate, and pH. The 28-day mortality rates of Group I, II, III, and IV were 18.3%, 23.6%, 32.6%, and 50.0%, respectively (p < .001). In Multivariable Cox proportional hazard regression analysis, the groups with lower serum TCO₂ concentrations had a higher risk of 28-day mortality compared with Group I: Group II (Hazard ratio (HR), 1.35; 95% confidence interval (CI), 1.11-1.64), Group III (HR, 1.74; 95% CI, 1.37-2.21), and Group IV (HR, 2.72; 95% CI, 2.03-3.64).

Serum TCO₂ concentrations of 20 mmol/l or less were associated with 28-day mortality in patients with sepsis.