Lactate Concentrations Evaluated In Suspected Infections

The relationship between blood lactate concentrations categorized into groups and mortality appears to be linear, but the relationship between lactate as a continuous measurement and mortality is uncertain.

The prognostic significance of incremental blood lactate concentrations among emergency department (ED) patients with suspected infection has been evaluated and categorized into low, intermediate, and high groups.

Scientists at the University of Mississippi Medical Center (Jackson, MS, USA) carried out a retrospective cohort analysis of adult ED patients with suspected infection from a large urban ED during January 2007 to May 2011. Over the study period, 2,596 patients met inclusion criteria and the median age was 61 years, the median hospital length of stay was eight days and the overall mortality was 14.4%.

The whole blood lactate measurements were performed in the ED using the i-STAT point-of-care (POC) measurement (Abbott Point of Care Inc.; Princeton, NJ, USA; www.abbottpointofcare.com ). The median initial lactate concentration was 2.1 mmol/L, and 459 (17.6%) subjects had an initial lactate greater than 4 mmol/L. Mortality continued to rise across the continuum of incremental elevations, from 6% for lactate greater than 1.0 mmol/L up to 39% for lactate 19-20 mmol/L. Polynomial regression analysis showed a strong curvilinear correlation between lactate and mortality.

The authors concluded that in ED patients with suspected infection, incremental elevations in whole blood lactate values up to 20 mmol/L are associated with progressive increases in mortality. Clinicians should be aware of the prognostic significance of incremental increases in lactate, even in the significantly elevated range, and should avoid considering all patients with a high lactate to be at similar risk of death. The study was published on August 20, 2012, in the journal Academic Emergency Medicine.

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University of Mississippi Medical Center
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