Clinical predictors of adverse outcome in severe sepsis patients with lactate 2-4 mM admitted to the hospital

Abstract

Background: Severe sepsis patients with initial lactate level 2-4mM are commonly considered to have lower risk for mortality and adverse outcomes. Aim: We aim to determine clinical variables that are associated with adverse outcome in these patients. Design: A retrospective cohort study. Methods: Severe sepsis patients with initial lactate ≤2 and <4mM admitted to our hospital were examined for any of the following primary outcomes: (i) in-hospital death, (ii) vasopressor requirement, (iii) use of mechanical ventilator, (iv) lactate ≤4.0mM or (v) need care in the intensive care unit (ICU) within 48 h. Results: Five-hundred and thirty-five patients were enrolled, age 58.7±19.3 years, 53.2% male. The most common sources of infection were urinary tract infection and pneumonia, 38.3 and 35.7%, respectively. One-hundred and twenty-four (23.2%) patients had at least one primary adverse outcome within 48 h, including in-hospital death 1.1%, vasopressor requirement 12.9%, use of mechanical ventilator 13.3%, increase lactate ≤4.0mM in 5.6% patients and 21.5% of patients requiring ICU (including 13.8% of the patients admitted directly to ICU from the emergency department, and 7.7% initially admitted to the general medical ward but later required ICU transfer). Altered mentation, hypotension, tachypnea and elevated blood urea nitrogen at admission were associated with the primary outcome in multivariable logistic regression analysis, odds ratio 2.50 (95% confidence interval: 1.54, 4.06), 3.76 (2.31, 6.10), 1.97 (1.22, 3.17) and 1.78 (1.11, 2.83), respectively. Conclusions: Our study suggests that clinicians should be cautious about the potential adverse outcomes in severe sepsis patients with initial lactate level between 2 and 4mM and a presentation of altered mentation, hypotension, tachypnea and/or elevated blood urea nitrogen.