Lactate: the Black Peter in high-risk gastrointestinal surgery patients

Lactate arises from metabolisation of glucose to pyruvate. Pyruvate either is transformed to or from lactate in the cytosol or converted by pyruvate dehydrogenase in mitochondria to acetyl coenzyme A which enters the Krebs cycle to produce energy for cellular metabolism. Any switch to anaerobic metabolism will reduce activity of the highly oxygen-dependent Krebs cycle and shunt “redundant” pyruvate towards lactate (1).