Analysis of correlations between blood lactic acid, lactate clearance rate and emergency stratification as well as prognosis in patients

Abstract

Objective To investigate the correlations between the level of blood lactic acid (Lac), lactate clearance rate (LCR) and emergency stratification Ⅰ or Ⅱ as well as the prognosis in patients. Methods A retrospective analysis was conducted. The clinical data of 370 critically ill patients with emergency stratification Ⅰ or Ⅱ accompanying with hyperlactacidemia admitted to emergency center of People's Hospital of Wuwei City during January 2013 to April 2015 were analyzed. The patients were allocated into two groups: Lac ≥ 10 mmol/L (n = 181) and Lac 4-10 mmol/L (n = 189). Base excess (BE), acute physiology and chronic health evaluation Ⅱ (APACHE Ⅱ) score and hospital mortality were compared between the two groups. The differences in initial Lac, 6-hour LCR and APACHE Ⅱ score were compared between survival group and death group as well as emergency stratification Ⅰ and Ⅱ groups. The correlation between initial Lac, 6-hour LCR and APACHE Ⅱ score was analyzed by Pearson correlation method. Results ① With the increase in Lac level, the negative deviation extent of BE and APACHE Ⅱ score in critical patients were gradually increased [BE (mmol/L): -16.74±8.21 vs. -5.98±8.43, APACHE Ⅱ score: 27.6±5.6 vs. 20.1±4.8], and hospital mortality was increased [76.79% (139/181) vs. 43.39% (82/189), all P < 0.01]. ② The initial Lac and APACHE Ⅱ score of the death group were significantly higher than those of the survival group [initial Lac (mmol/L): 8.81±4.71 vs. 4.43±2.82, APACHE Ⅱ score: 23.6±5.6 vs. 17.3±3.7], and 6-hour LCR was significantly decreased [(12.26±6.47)% vs. (35.16±10.63)%, all P < 0.01]. ③ Patients in emergency stratification Ⅰ group had a higher initial Lac and a higher APACHE Ⅱ score but a lower 6-hour LCR level than those in emergency stratification Ⅱ group [initial Lac (mmol/L): 8.7±2.6 vs. 6.8±2.0, APACHE Ⅱ score: 25.2±6.3 vs. 16.3±4.7, 6-hour LCR: (14.8±4.7)% vs. (33.5±5.8)%, both P < 0.01]. ④ It was shown by correlation analysis that initial Lac was significantly positively correlated with APACHE Ⅱ score (r = 0.731, P = 0.017) in 370 emergency critical ill patients, while 6-hour LCR was negatively correlated with APACHE Ⅱ score (r = -0.694, P = 0.010). Conclusions The early arterial blood Lac of patients with emergency stratification Ⅰ was significantly higher than emergency stratification Ⅱ, and the 6-hour LCR in patients with emergency stratification Ⅱ was significantly higher than emergency stratification Ⅰ. Furthermore, the Lac level and LCR were simple and easy to implement as compared with APACHE Ⅱ score in emergency critical ill patients. Key words: Arterial blood lactate; Lactate clearance rate; Emergency stratification; Prognosis evaluation