ABSTRACT
Objective To investigate the prognostic significance of serum lactate level and lactate clearance rate for critical illness patients.Methods Two hundred and eighty-six patients with hyperlactacidemia were investigated by analyzing the clinical data,laboratory data and outcomes.Comparison of mortality rate and APACHE Ⅱ score between different stratified levels of serum lactate was carried out.The blood pH,HCO3-,BE,and Lac were compared between survivors and non-survivors in terms of in-hospital death in seven days after admission.The above variables of blood gas analysis were studied in patients with severe hyperlactacidemia as well as the different lactate clearance rates and APACHE Ⅱ scores were compared between survivors and non-survivors.The mortality rates and APACHE Ⅱ scores were compared between high and low lactate-clearance rate groups.Results The mortality rates of different stratified levels of serum lactate (≥2,＜4 mmol/L; ≥4,＜ 10mmol/L; ≥ 10 mmoL/L) were 14.04％,46.67％,78.79％,respectively.As the serum level of lactate increased,the decompensation rate of pH,APACHE Ⅱ score and mortality rate increased consequently.Compared with non-survivors,survivors had a higher lactate clearance rate (P ＜ 0.01),and lower APACHE Ⅱ score (P ＜ 0.01).The high-clearance group had lower mortality rate and 6-hour APACHE Ⅱ score compared with the low-clearance group (P ＜ 0.01),but the initiate levels of serum lactate and APACHE Ⅱ scores were not noticeably different between the two groups (P ＞ 0.05).Serum lactate level had a significant positive relationship with APACHE Ⅱ score (r =0.868,P ＜ 0.01),but lactate clearance rate had a significant reverse relationship with APACHE Ⅱ score (r =-0.823,P ＜ 0.01).Conclusions Both serum lactate levels and early lactate clearance rate had high prognostic value for critical illness patients,and in combination with changes in APACHE Ⅱ score,they could guide clinical treatment and give precise evaluation of the prognosis.