• R Meierhans, G Brandi, M Fasshauer, J Sommerfeld, R Schüpbach, M Béchir, and J Stover.
• Surgical Intensive Care, University Hospital Zürich, Zürich, Switzerland.
• Minerva Anestesiol. 2012 Feb 1;78(2):185-93.

BackgroundLactate fuels cerebral energy-consuming processes and it is neuroprotective. The impact of arterial lactate on brain metabolism determined by microdialysis was investigated retrospectively in patients with severe traumatic brain injury (TBI).MethodsCerebral microdialysis (glucose, lactate), neuromonitoring (ICP, CPP, ptiO2, SjvO2) and blood gas data collected in 20 patients during pharmacologic coma were grouped within predefined arterial lactate clusters (<1, 1-2, >2 mM). Microdialysis samples were only taken from time points characterized by normoventilation (paCO2 34.5-42 mmHg), sufficient oxygenation (paO2 >75 mmHg) and hematocrit (≥24%) to exclude confounding influences.ResultsElevated arterial lactate ≥2 mM was associated with significantly increased brain lactate which coincided with markedly decreased brain glucose despite significantly increased arterial glucose levels and sufficient cerebral perfusion indirectly determined by normal SjvO2 and ptiO2 values. At elevated arterial lactate levels signs of significantly increased cerebral lactate uptake coincided with markedly decreased cerebral glucose uptake. Infused lactate above 50 mM per 24 hours was associated with significantly decreased cerebral glucose.ConclusionIncreased arterial lactate levels were associated with increased cerebral lactate uptake and elevated brain lactate. At the same time brain glucose uptake and brain glucose were significantly reduced. It remains unclear whether arterial lactate is the driving force for the increased cerebral lactate levels or if the reduced glucose uptake also contributed to the increased cerebral lactate levels. Further studies are required to assess the impact of lactate infusion under clinical conditions.

20 keywords...

hide…