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   Coverpages
   Preface
   Introduction
   Chapter 1 - Body Fluids
   Chapter 2 - Goals, Definitions, and Basic Principles
   Chapter 3 - The Simplest Acid-Base System: Pure Water
   Chapter 4 - Stron Ions and the Strong Ion Difference
   Chapter 5 - Weak electrolytes and buffers
   Chapter 6 - Strong ions plus carbon dioxide (isolated, intact interstitial fluid)
   Chapter 7 - Strong ions plus carbon dioxide plus weak acid: isolated blood plasma and isolated intracellular fluid
   Chapter 8 - Interactions between body fluids
   Chapter 9 - Whole-body acid-base balance

Introduction

Acid-base chemistry is an important topic in biology, biochemistry, physiology, and clinical medicine, a topic that should be thoroughly understood by everyone in these fields. Despite this importance, the topic is usually approached in a piecemeal, qualitative, and confusing way, so that misunderstanding and disagreement seem to be much more common than the kind of useful quantitative understanding that is needed. The reason is partly that acid-base chemistry, like many topics in biology and medicine, can only be simplified down to a certain minimum level before serious errors and misinterpretations result. This minimum level is the elementary physical chemistry of aqueous solutions containing ions. Its major message is that we can only make sense of acid-base behavior of body fluids by taking into account how all the ions, not just hydrogen ions, participate in that behavior; hydrogen ions in body fluids cannot be understood as independent entities. Treating that elementary chemistry quantitatively, as we shall do in this book, not only enables us to understand hydrogen ion behavior clearly, it also relates that behavior to fluid and electrolyte balance in the whole organism in a direct and coherent way. Mastering the elementary chemistry is therefore well worth the minor effort involved.

We present the minimum necessary physical and chemical principles in Chapter 2. The rest of the book will then demonstrate their relevance and power by explaining the apparent complexities of acid-base phenomena in simple but thorough and quantitative terms. The treatment will progress from the simplest system, pure water, in Chapter 3, through progressively more complex solutions and body fluids in succeeding chapters, to the final, surprisingly simple treatment of whole-body acid-base balance in Chapter 9.

Modem chemistry, even at the elementary level needed to understand hydrogen ion behavior, is largely understood in quantitative, and therefore mathematical, terms. Until recently, that mathematics has been avoided in acid-base chemistry for the sensible reason that it was not very much help before computers became available. Hydrogen ion concentration, the focus of acid-base chemistry, depends on severable variables, and the quantitative description of its behavior requires many simultaneous equations. Explicit analytical solutions for such sets of equations, when they can be written at all, are not usually regarded as useful because they are so unwieldy for practical calculations. Computers, including handheld programmable calculators, have completely changed this situation; numerical values for the solutions to such equations are now easily and rapidly obtained by computer-implemented techniques of numerical analysis. As a result, computers have revolutionized our ability to analyze, understand, and predict the acid-base behavior of body fluids, or any solutions of biological or medical interest. This book is both an exposition, and an exploitation for its practical usefulness, of that revolution.

The treatment of acid-base chemistry and biology in this book is necessarily not at all like the treatments in current textbooks and research journals. References to previous literature are therefore sparse. There are so many differences in detail between the quantitative analytical treatment presented here and the conventional qualitative treatments that compar- isons with even a few of the classical descriptions would have greatly increased the size of this book. It seemed more valuable in this introductory account to concentrate on the basic principles, and their important quantitative consequences, leaving to the reader the task of comparison and translation.

The nonmathematically oriented reader may ask at this point, how much of this new quantitative understanding of acid-base can be achieved without actually working through all the tedious details of the mathematics and the computer programs? The answer supplied by this book is that the minimum level of mathematical sophistication required is only that needed to appreciate what the relevant equations mean, why they must be true, and how they are related to each other. How they are to be solved can then be treated as an incidental technical problem. Most of the mathematical details therefore appear in appendices to the appropriate chapters rather than in the main text. They are there for those who want them, but for those who do not, they will not interrupt the flow of the main arguments. What we want to know is what the mathematics tells us about the behavior of all the variables in body fluids, especially hydrogen ion concentration, once we have specified the quantitative constraints on that behavior that the laws of physics and chemistry require. Once calculated by the computer, that behavior is readily understood from computer-generated graphs and tables of values. These provide qualitative as well as quantitative pictures of the acid-base behavior of each solution.

In summary, this book presents a nontraditional treatment of acid-base behavior in body fluids. Its purpose is to help the reader work through the elementary physical chemistry of ionic solutions to the synthesis of a clear, quantitative, and practical understanding of how and why hydrogen ion concentration behaves as it does in those solutions and in the whole organism.

>>next: Chapter 1 - Body Fluids