Risk Stratification of Patients with Acute Respiratory Distress Syndrome Complicated with Sepsis Using Lactate Trajectories

Background: No consensus has been reached on an optimal blood lactate evaluation system although several approaches have been reported in the literature in recent years. A group-based trajectory modeling (GBTM) method could better stratify patients with acute respiratory distress syndrome (ARDS) complicated with sepsis in the intensive care unit (ICU). Methods: : 762 patients from the comprehensive ICU of Tianjin Medical University General Hospital with ARDS complicated with sepsis were eligible for analysis. Serial serum lactate levels were measured within 48 h of admission. In addition to the GBTM lactate groups, the initial lactate, peak lactate level, the area under the curve of serial lactate (lactate AUC), and lactate clearance were also considered for comparison. The short- and long-term outcomes were the 30- and 90-day mortality rates, respectively. Results: : Three lactate groups were identified based on GBTM, with group 3 exhibiting the worse short- (hazard ratio (HR): for 30-days mortality: 2.26, 95% CI: 1.75 to 2.92, P <0.001) and long term (HR for 90-day mortality: 3.06, 95% CI: 1.78 to 5.27, P <0.001) outcomes followed by group 2 [HR for 30-day mortality: 1.79, 95% confidence interval (CI): 1.30 to 2.47, P <0.001] and HR for 90-days mortality: 1.73, 95% CI: 1.30 to 2.31, P <0.001). GBTM lactate groups exhibited significantly improved diagnostic performance of initial lactate + SOFA scores/APACHE II scores models. Based on the multivariable fractional polynomial interaction (MFPI) approach, GBTM lactate groups could better differentiate high-risk patients than the initial lactate groups in short- and long-term outcomes. Conclusions: : To the best of our knowledge, this is the first report that GBTM-based serial blood lactate evaluations significantly improve the diagnostic capacity of traditional critical care evaluation systems and bring many advantages over previously documented lactate evaluation systems.