Few laboratory values receive as much attention in critical care as lactate. Elevated lactate levels often trigger aggressive resuscitation efforts, serial measurements, and heightened concern for impending circulatory collapse.
While lactate is undeniably an important biomarker, it is frequently misunderstood. One of the most persistent myths in critical care is that elevated lactate automatically indicates tissue hypoxia.
Under normal conditions, glucose undergoes glycolysis to produce pyruvate. Pyruvate may then enter the mitochondria for aerobic metabolism or be converted into lactate by lactate dehydrogenase.
During critical illness, lactate may rise for numerous reasons beyond inadequate oxygen delivery. Adrenergic stimulation is one of the most important mechanisms.