Initial lactate level and mortality in septic shock patients with hepatic dysfunction

Abstract

An elevated serum lactate level is associated with morbidity and mortality in patients with severe sepsis and septic shock. In patients with hepatic dysfunction, however, an elevated serum lactate level may be due to either impaired lactate clearance or excessive production. Thus, we evaluated whether the initial serum lactate level was also associated with mortality in septic shock patients with hepatic dysfunction. A retrospective observational study enrolled 307 patients with septic shock admitted to the intensive care unit (ICU) between May 2007 and July 2009. Hepatic dysfunction was defined as a serum total bilirubin >34.2 μmol/l (2 mg/dl). Selected patients were divided into high (≥4 mmol/l) and low (<4 mmol/l) lactate groups, according to the initial serum lactate level. Of 307 patients with septic shock, 118 (38%) patients with hepatic dysfunction were eligible for this study. The median lactate levels were 5.9 (interquartile range 4.7 to 9.0) and 2.6 (interquartile range 1.7 to 3.2) mmol/l for the high and low lactate groups respectively (P <0.001). The initial serum lactate level was strongly associated with in hospital mortality in a univariate analysis (P <0.001). After adjusting for potential confounding factors, the initial serum lactate level remained significantly associated with in-hospital mortality (odds ratio 1.281, 95% confidence interval 1.097 to 1.496, P=0.002). In conclusion, the serum lactate level could be useful in predicting the outcome of patients with septic shock regardless of hepatic dysfunction.