Arterial Lactate Level a Reliable Prognostic Predictor for Septic Shock

Lactate test, blood test
Lactate test, blood test
Researchers evaluated the prognostic significance of the cutoff value for lactate via comparison of clinical presentation and outcome between patients with septic shock with high and low lactate levels.

Patients with septic shock and hyperlactatemia had poorer prognoses and a high Sequential Organ Failure Assessment (SOFA) scores were significant in predicting lactate levels, according to research published in The Journal of Microbiology, Immunology and Infection.

Revised definitions of septic shock deem vasopressor therapy and hyperlactatemia essential for diagnosis. However, cutoff values for lactate levels and prognostic factors in patients with septic shock and hypolactatemia remain unclear. Therefore, analysis of a retrospective observational cohort of 1022 eligible patients who met the new definition of septic shock was performed to evaluate the prognostic significance of the cutoff value for lactate via comparison of the clinical presentation and outcomes in high- and low-lactate patient groups.

A total of 653 patients met the study criteria of high lactate levels, defined as patients with arterial lactate >2 mmol/L and 369 patients had an arterial lactate level ≤2 mmol/L. Organ failure was significantly more frequent in the high-lactate group. In the high-lactate group, 7-day and 28-day mortality was also significantly higher than in the low-lactate group (10.3% vs 1.6%; P <.001; 15.6% vs 4.9%; P <.001, respectively). SOFA score was a significant variable in predicting arterial lactate, showing positive correlation with serum lactate in simple correlation analysis (r = .394; P <.001) and linear regression (R2 = .155; P <.001).

Study data were limited to a single center. Also, patients with nosocomial infections and patients undergoing surgeries with high likelihood of septic shock were excluded, limiting the data and applicability to these clinical scenarios.

“Re-examination of arterial lactate should be considered when treating patients with suspected septic shock and low arterial lactate,” noted the investigators. “Further studies are needed that will identify other predictive factors for high-risk cases of septic shock without hyperlactatemia,” they added.

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Hyun Oh D, Hyun Kim M, Yong Jeung W, et al. Risk factors for mortality in patients with low lactate level and septic shock [published online August 26, 2017]. J Microbiol Immunol Infect. doi:10.1016/j.jmii.2017.08.009