Stewart’s Textbook of Acid-Base. Edited by John A. Kellum, M.D., and Paul W. G. Elbers, M.D. London, United Kingdom, Lulu Enterprises, UK Ltd., 2009. Pages: 504. Price: $88.13.

Stewart’s Textbook of Acid-Base  edited by John Kellum, M.D. and Paul Elbers, M.D., consists of a reprint from Dr. Peter Stewart’s original text in 1981, How to Understand Acid-Base.  This reprint provides Dr. Stewart’s original concepts of the physicochemical and quantitative approach to acid-base physiology. The new text has 20 well-referenced chapters, written by authoritative authors in the field, that review the development of quantitative acid-base physiology over the last 20 yr.

In Stewart’s approach, the strong ion difference [[Na+]+[K+]+[Ca++]+[Mg++]]−[[Cl−]+[lactate−]], total weak acids (protein, phosphate etc.) and pCO2are seen as independent determinants of pH. In contrast, bicarbonate and protons are variable dependents in the physicochemical approach but play a central role in the classic approach.

This book is published by,*a Web site that over the past few years was the easiest way to read Stewart’s original text (it is still available on the Web site). This Web site serves as an additional resource and includes useful clinical calculators that make analysis of even complex cases easy from a mathematical standpoint. In addition to serving as a calculator, the Web site can be used as an excellent teaching tool with its ability to graphically display acid-base analysis results and plot them over time.

Much has been written about the advantages and disadvantages of Stewart’s approach versus  the conventional bicarbonate-centered approach to acid-base physiology. The basic advantages of Stewart’s approach are nicely summarized in this book’s foreword, where emphasis is placed on the benefits of unifying acid-base physiology and electrolytes into one concept. This approach enables practitioners to gain a panoramic view of physiologic imbalances. It is especially useful for students of the field who struggle to achieve oversight while being taught to examine a complex interplay of systems in a disjointed way that never reveals the full picture.

This book serves as an excellent resource for all who are interested in acid-base physiology. It offers a depth of knowledge well beyond of what is necessary for daily practice. Ironically, it is so well referenced that it also will serve as a useful starting point for further reading in this field.

The newly written part of this book is divided into two subsections. One subsection deals with more basic concepts, including advances in the understanding of the influence of weak acids such as proteins on pH, acid-base physiology in pregnancy, or intracellular pH. The other details the clinical applicability of Stewart’s approach at the bedside and its use in understanding, among others, concepts of hyperchloremic and lactic acidosis, as well as the effect liver and renal failure have on acid-base homeostasis.

The authors were largely successful in continuing Stewart’s clear style. They avoid losing the reader while going through a series of fairly complex calculations and formulas. Bedside applicability of a large number of chapters, especially when used in combination with the online calculator, is excellent.

The authors note their desire that this book enable readers to view the field more clearly, no matter what their primary approach. They base this desire on a change of perspective rather than requiring a restart of the prior controversy regarding the superiority of one approach to interpretation of acid-base physiology over another. Given the excellent resource this book offers, the quantitative physicochemical approach to one of the most common clinical problems becomes more practical. This, in turn, makes Stewart’s Textbook of Acid-Base a useful stepping-stone for upgrading one’s acid-base analysis from rule-of-thumb–driven to data-driven.

Mayo Clinic, Rochester, Minnesota.