Wettervik TS, Engquist H, Howells T, et al. - Researchers investigated the link of endogenous arterial lactate with systemic physiology, pressure autoregulation, cerebral energy metabolism, and clinical outcome in traumatic brain injury (TBI) in this retrospective analysis. Participants were patients (n = 115) (consent given) with severe TBI managed in the neurointensive care unit between 2008 to 2018. On day 1 after injury, arterial lactate peaked and slowly reduced thereafter. A multiple regression analysis revealed a correlation of higher arterial lactate with lower age, higher Marshall score and higher arterial glucose. Higher arterial lactate was found to be related to poor pressure autoregulation, but not to worse cerebral energy metabolism. Unfavorable clinical outcome was reported in relation to higher arterial lactate. Based on these data, high endogenous arterial lactate was concluded as a biomarker of poor systemic physiology and may disturb cerebral blood flow autoregulation.