The Association of Perioperative Serum Lactate Levels with Postoperative Delirium in Elderly Trauma Patients

BACKGROUND: Several studies have shown the utility of lactate level as a predictor of early outcomes in trauma patients. We conducted this study to evaluate the association of perioperative serum lactate levels with postoperative delirium (POD) in elderly trauma patients. MATERIALS AND METHODS: This study included 466 elderly trauma patients with measurements of serum lactate levels on admission and 1 h after surgery. The associations of POD with serum lactate levels (on admission and 1 h after surgery) and lactate clearance were analyzed using Kendall's correlation. Perioperative serum lactate levels and lactate clearance as predictors of POD were evaluated using univariate and multivariable analyses. RESULTS: The incidence of POD in the present study was 38.1%. Serum lactate levels on admission and at 1 h after surgery were significantly higher in major trauma than in minor trauma. In univariate analysis of perioperative serum lactate levels and lactate clearance as predictors of POD, the odds ratio (OR) for serum lactate level on admission was 4.19 (P < 0.01, 2.91 < 95% confidence interval (CI) < 6.02) and that 1 h after surgery was 3.83 (P < 0.01, 2.79 < 95% CI < 5.25); however, the OR for serum change of lactate level was 0.99 ((P < 0.09, 0.99 < 95% CI < 1.00). In multivariable analysis for predictors of POD, the OR for serum lactate level on admission was 2.40 (P < 0.09, 0.87 < 95% CI < 6.7), that for serum lactate 1 h after surgery was 2.83 (P=0.01, 1.28 < 95% CI < 6.24), that for ICU admission was 3.01 (P=0.01, 2.09 < 95% CI < 6.03), and that for ISS was 1.47 (P < 0.01, 1.27 < 95% CI < 3.70). CONCLUSIONS: Taking together the results of univariate and multivariable analyses, serum lactate level 1 h after surgery may be used as a prediction model of POD development in elderly trauma patients.