title: Lactate as a marker of energy failure in critically ill patients: hypothesis.
abstract: Lactate measurement in the critically ill has been traditionally used to stratify patients with poor outcome. However, plasma lactate levels are the result of a finely tuned interplay of factors that affect the balance between its production and its clearance. When the oxygen supply does not match its consumption, organisms such as man who are forced to produce ATP for their integrity adapt in many different ways up to the point when energy failure occurs. Lactate, being part of the adaptive response, may then be used to assess the severity of the supply/demand imbalance. In such a scenario, the time to intervention becomes relevant: early and effective treatment may allow the cell to revert to a normal state, as long as the oxygen machinery (i.e. mitochondria) is intact. Conversely, once the mitochondria are deranged, energy failure occurs even in the presence of normoxia. The lactate increase in critically ill patients may therefore be viewed as an early marker of a potentially reversible state.
authors.affiliation: Istituto di Anestesia e Rianimazione, Università degli Studi di Milano, Ospedale Maggiore Policlinico, Mangiagalli e Regina Elena--Fondazione IRCCS di Natura Pubblica, Milan, Italy. franco.valenza@unimi.it
authors.forename: Franco
authors.initials: F
authors.lastname: Valenza
authors.forename: Gabriele
authors.initials: G
authors.lastname: Aletti
authors.forename: Tommaso
authors.initials: T
authors.lastname: Fossali
authors.forename: Giorgio
authors.initials: G
authors.lastname: Chevallard
authors.forename: Francesca
authors.initials: F
authors.lastname: Sacconi
authors.forename: Manuela
authors.initials: M
authors.lastname: Irace
authors.forename: Luciano
authors.initials: L
authors.lastname: Gattinoni
mesh_terms: D000136:Acid-Base Equilibrium; D015415:Biomarkers / Q000097:blood; D003422:Critical Care / Q000379:methods*; D016638:Critical Illness / Q000145:classification; D018450:Disease Progression; D004734:Energy Metabolism; D006801:Humans; D000860:Hypoxia / Q000097:blood / Q000503:physiopathology; D019344:Lactic Acid / Q000097:blood*; D012016:Reference Values; D012720:Severity of Illness Index
chemical_list: D015415:Biomarkers; D019344:Lactic Acid