Abstract
Elevations in blood lactate concentrations have been studied in sepsis and other disease
states for decades and are well known to be associated with increased mortality. Many
studies have also demonstrated the prognostic accuracy of serial lactate levels, and
some have suggested that lactate clearance may be a useful therapeutic target for
resuscitation. Lactate measurements have therefore gained an increasingly prominent
role in sepsis definitions, screening protocols, management guidelines, and quality
measures over the past two decades. The heavy emphasis on lactate monitoring, however,
has also generated controversy and concerns. Lactate is not specific to infection
and its frequent use for sepsis screening and diagnosis may therefore trigger unnecessary
broad-spectrum antibiotic use in some patients. Because hyperlactatemia does not always
reflect fluid-responsive hypoperfusion, titrating resuscitation to lactate clearance
can also lead to unnecessary fluid and volume overload. More broadly, there is a lack
of high-quality evidence demonstrating that initial and serial lactate monitoring
leads to better patient-centered outcomes. Indeed, a recent randomized controlled
trial comparing resuscitation strategies based on lactate clearance versus normalizing
capillary refill time showed no benefit and potential harm with lactate-guided therapy.
In this article, we review the basic pathobiology of lactate metabolism and delineate
why the traditional paradigm that hyperlactatemia reflects tissue hypoxia is overly
simplistic and incomplete. We then review the evidence behind the diagnostic, prognostic,
and therapeutic uses of lactate monitoring and place this in the context of evolving
sepsis diagnosis and management guidelines.
Keywords
lactate - lactic acidosis - hyperlactatemia - sepsis - septic shock - lactate clearance
