Mildly Elevated Lactate Levels Are Associated With Microcirculatory Flow Abnormalities And Increased Mortality: A Microsoap Post Hoc Analysis

Background Mildly elevated lactate levels (i.e., 1–2 mmol/L) are increasingly recognized as a prognostic finding in critically ill patients. One of several possible underlying mechanisms, microcirculatory dysfunction, can be assessed at the bedside using sublingual direct in vivo microscopy. We aimed to evaluate the association between relative hyperlactatemia, microcirculatory flow, and outcome. Methods This study was a predefined subanalysis of a multicenter international point prevalence study on microcirculatory flow abnormalities, the Microcirculatory Shock Occurrence in Acutely ill Patients (microSOAP). Microcirculatory flow abnormalities were assessed with sidestream dark-field imaging. Abnormal microcirculatory flow was defined as a microvascular flow index (MFI) 1.5 mmol/L was independently associated with a MFI < 2.6 (OR 2.5, 95% CI 1.1–5.7, P = 0.027). Conclusions In a heterogeneous ICU population, a single-spot mildly elevated lactate level (even within the reference range) was independently associated with increased mortality and microvascular flow abnormalities. In vivo microscopy of the microcirculation may be helpful in discriminating between flow- and non-flow-related causes of mildly elevated lactate levels. Trial registration ClinicalTrials.gov, NCT01179243. Registered on August 3, 2010. Electronic supplementary material The online version of this article (doi:10.1186/s13054-017-1842-7) contains supplementary material, which is available to authorized users.PubMedWoSScopu