«Background: By the turn of the 20th century, it had become apparent that patients who are critically ill could exhibit metabolic acidosis unaccompanied by elevation of ketones or other measurable anions. In 1925, Clausen identified the accumulation of lactic acid in blood as a cause of acid-base disorder. Several decades later, Huckabee's seminal work firmly established that lactic acidosis frequently accompanies severe illnesses and that tissue hypoperfusion underlies the pathogenesis. In their classic 1976 monograph, Cohen and Woods classified the causes of lactic acidosis according to the presence or absence of adequate tissue oxygenation. ~ [...]»