Acid-base homeostasis: a historical inquiry of its origins and conceptual evolution

To a great extent, the conceptual evolution of acid-base homeostasis has been shaped by progress in chemistry. It began with the theoretical consideration of matter by the natural philosophers of antiquity, progressed into an observational craft as chymistry during the Scientific Revolution, evolved into analytical chemistry in the Enlightenment when acid-alkali interactions began to be deciphered, then was clearly exposed in the organic chemistry of the 19th century and ultimately formulated in mathematical precision as the chemical equations of physical chemistry in the 20th century. Two principal transformational changes shaped their clinical application. The first, launched by the Chemical Revolution of Antoine Lavoisier, introduced quantitation, clarified the language and added experimental rigor to chemical studies, which Claude Bernard then introduced into physiology, formulated the concept of regulatory homeostasis, refined experimental medicine and explored the role of the kidney in acid-base balance. The second transformational change in their gradual clinical applicability began in electrochemical studies that revived the atomic composition of matter and introduced the notion of ions and electrolytes that were fundamental in formulating the concept of acid-base ionization by Svante Arrhenius in 1884 and their measurement from hydrogen ion concentration as pH by Søren Sørensen in 1909. Subsequent studies of Lawrence J. Henderson and Donald D. van Slyke introduced these laboratory-based conceptual advances to the bedside in the 20th century. Clinical studies of acidosis and alkalosis that followed over the past few decades have facilitated and refined the clinical recognition, interpretation and treatment of acid-base disorders.