The 100th anniversary of the invention of pH (1909-2009) - Part II. Was it really necessary to replace the Henderson equation with that of Henderson-Hasselbalch?

Abstract

Introduction: The year 2009 marked the centenary of the ‘‘invention’’ of the concept of pH by the Danish chemist-mathematician Søren Peder Lauritz Sørensen (1868-1939), who was working at the time in the chemistry laboratories of the Carlsberg Brewery in Copenhagen. The occasion provides an opportunity to re-examine a concept that is crucial for the understanding of human life–—namely, acid-base balance. This article provides an overview of acid-base pathophysiology and the historical events that led from the simple equation of Henderson to the much more complex one developed by Hasselbalch. Conclusions: The authors conclude that the issue of acid-base balance would be easier to understand, more exciting, and even more pleasant if it were taught without recourse to the infamously abstruse Henderson-Hasselbalch equation. Unquestionably, the whole rationale underlying the understanding and clinical application of this vital concept is already inherent in the simpler, more manageable formula of Henderson (without logs), which is both useful and sufficient for use in medical school curricula.

Keywords

• pH
• History of pH
• Centenary of pH
• Acid-base balance
• Henderson equation
• Henderson-Hasselbalch equation
• Logarithms in medicine.