Peter A. Stewart

Peter A. Stewart, born on January first, nineteen twenty-one, was a distinguished Canadian physiologist renowned for his innovative contributions to the field of acid-base physiology. His groundbreaking work introduced an alternative perspective that has since influenced both academic and clinical practices.

In nineteen seventy-eight, Stewart outlined his model in a pivotal paper, which he later elaborated on in his influential book, How to Understand Acid–Base, published in nineteen eighty-one. Although the book was unavailable for many years, it was eventually made accessible online and reprinted in two thousand nine, featuring additional chapters that address contemporary applications in clinical medicine.

Stewart's approach to acid-base balance models the intricate chemical equilibrium system, introducing the term 'strong ion difference' or [SID]. This term refers to the concentration of strongly dissociating cations minus that of strongly dissociating anions. He identified this alongside total weak acid concentration and the partial pressure of CO2 as independent variables, formulating a quartic equation that relates [H+] to these variables. Notably, this equation has been solved numerically by computer but has yet to be validated through titration or physiological experiments.

While the impact of Stewart's analysis has been gradual, there has been a recent resurgence of interest in his work. His model provides valuable insights into complex areas of acid-base disorders, such as dilutional acidosis and conditions related to fluctuations in plasma albumin concentration, making his contributions increasingly relevant in modern medicine.