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Foreword to the First Edition
Foreword to the First Edition LEWIS A. BARNESS, M.D.
Reviews of fluid therapy, like water, are everywhere. Some are more comprehensible than others, and the tendency is to make them simpler as understanding becomes better. When Drs. James Gamble, Alan Butler, Daniel Darrow and George Guest were first discovering the 70 to 80 per cent place of fluid in the body, they were considered a breed apart and labelled "salt and water boys." The label is finally being dropped as more knowledge brings ready use of their principles of fluid therapy. That pediatricians should be most interested of all physicians in exactness in fluid therapy arises from two basic causes. Pediatricians traditionally have been in the vanguard of scientific advances in medicine. Indeed, some even believe that pediatrics split off from internal medicine in order to develop science as well as art in medicine. Pediatricians were part mathematicians: thereby the sad tale of early pediatrics, with rigid formulas for babies, rigid schedules for babies and, finally, rigid babies. A more valid reason for exactness in fluid therapy in children is that small changes in fluid intake, though negligible in an adult, may be disastrous in a small child with small total fluid volume. Thus the surgeon for an adult can easily say, "Hang up a bottle of glucose water," knowing that the entire bottle contains only 5 per cent of the adult's extracellular volume and that he can easily adjust for any small errors in salt and water. A baby, on the other hand, may have a total extracellular fluid volume not much greater than that same bottle and may have immature kidney and liver function; therefore fluid therapy must be much more clearly defined as to total volume, rate of infusion, and electrolyte and water content. Fluid therapy of children is simple. Those who consider it complicated either have had too little experience or have a psychologic block about some formidable formulas. Unfortunately, in their desire to make fluid therapy universally applicable, some leaders in salt and water therapy have been seeking common denominators which are not so common in practice.
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792
FOREWORD TO THE FIRST EDITION
A few of these denominators are agreed on by all, and should be used by all physicians. First, regardless of how accurately fluids are calculated, the best evidence of proper fluid therapy is the patient. Therefore the patient should be carefully watched while fluids are being administered parenterally, and therapy should be adjusted according to the patient's response. Second, the best evidence of degree of hydration in a child is change of weight. Therefore all children receiving parenteral fluids should be weighed daily. Third, physicochemical responses of ions occur in proportion to their equivalents, and not according to gram weights. Therefore serum electrolytes and electrolytes administered should be in terms of milliequivalents (mEq.) or millimols (mM.), not milligrams (mg.). Those reared in an atmosphere of milligrams should convert to the more physiologic ionic milliequivalents: mEq. per liter
mg./IOO ml. X 10 atomic wt.
---'::.-.-----X valence
For a few commonly used ions: ION
VALENCE
Na K
1 1
Cl
1 2
Ca ...................... .
ATOMIC WT.
23 39 36 40
Volumes per cent of carbon dioxide may be converted to millimeters per liter by dividing by 2.2. Further details are discussed by Dr. Bergstrom (p. 795). This is practically the end of the areas of common agreement in therapy. In this volume it will be noted that some authors prescribe fluids on the basis of weight of the patient; others on the basis of surface area; and still others according to the number of calories utilized. Obviously, none is satisfactory, or one system would be universally adopted. The problems involved with all these systems are clearly covered by Dr. Darrow in his clinic (p. 819). Whether salt should be expressed in terms of water in the body or water according to its salt content, each physician can decide. Drs. Metcoff and Crawford have used systems which contain both concepts. Sometimes it seems as if we must stand on our heads to appreciate the more physiologic concept of concentration of water. Dr. Holliday, however, who discusses the physiology of dehydration, uses the more conventional concept of concentration of salt. Each of the authors of the section on Clinical Applications has apologized for "having to include some physiology" in his discussiona real'tribute to pediatricians. Therefore some duplication occurs. Fortunately, this makes for easier reading as each pathologic condition is discussed fully. More information is included in some of the clinical articles than
FOREWORD TO THE FIRST EDITION
793
is indicated in the title. For example, Dr. Kaye includes new data on fat solutions as well as techniques of fluid administration through all portals. Dr. Cooke clearly gives concise information not only of diarrhea and vomiting, but also of tricks of fluid therapy; Drs. Guest and Wallace go far beyond simple fluid therapy; Dr. Gardner answers well the question of how fluid therapy differs in children with infection; and the various aspects of surgical fluids are covered in the two papers of Drs. Colle and Paulsen, and Wolferth and Peskin.... Dr. Harrison discusses the still controversial problem of hyperelectrolytemia, and Dr. Cornfeld discusses a syndrome about which we are hearing less and less. Dr. Bongiovanni has recently written on the "Proper Use of Adrenal Hormonal Drugs," so that he quite aptly tells now what to do if the "hormonal drugs" are used improperly. Dr. Barbero discusses the theoretical as well as the practical aspects of fluid therapy in a troublesome respiratory disease which should be the battleground of fluid therapists; and Dr. Engle advises mainly against fluid therapy in the "fluid therapy of heart failure." Dr. Crawford's article is not only an admirable discussion of fluid therapy, but also an admirable presentation in humility . . . . Dr. Oski mentions briefly some of the possibilities in chemistry at the bedside, and Dr. Mellman puts the reader in the proper psychologic approach for good bloodletting. The Editor would like to note also that Drs. John Reinhold and Howard Rawnsley of the Pepper Laboratories, Hospital of the University of Pennsylvania, gave aid and advice in the preparation of several of the papers included in this volume. From this brief review it is noted that the minor ions are apparently not mentioned. This is not so. So far as data are available on such ions as magnesium and phosphate, these are included where applicable. As these ions attain their proper place in the minds of the "salt and water boys," a new review on fluid therapy will appear.
Reviews of fluid therapy, like water, are everywhere. Some are more comprehensible than others, and the tendency is to make them simpler as understanding becomes better. When Drs. James Gamble, Alan Butler, Daniel Darrow and George Guest were first discovering the 70 to 80 per cent place of fluid in the body, they were considered a breed apart and labelled "salt and water boys." The label is finally being dropped as more knowledge brings ready use of their principles of fluid therapy. That pediatricians should be most interested of all physicians in exactness in fluid therapy arises from two basic causes. Pediatricians traditionally have been in the vanguard of scientific advances in medicine. Indeed, some even believe that pediatrics split off from internal medicine in order to develop science as well as art in medicine. Pediatricians were part mathematicians: thereby the sad tale of early pediatrics, with rigid formulas for babies, rigid schedules for babies and, finally, rigid babies. A more valid reason for exactness in fluid therapy in children is that small changes in fluid intake, though negligible in an adult, may be disastrous in a small child with small total fluid volume. Thus the surgeon for an adult can easily say, "Hang up a bottle of glucose water," knowing that the entire bottle contains only 5 per cent of the adult's extracellular volume and that he can easily adjust for any small errors in salt and water. A baby, on the other hand, may have a total extracellular fluid volume not much greater than that same bottle and may have immature kidney and liver function; therefore fluid therapy must be much more clearly defined as to total volume, rate of infusion, and electrolyte and water content. Fluid therapy of children is simple. Those who consider it complicated either have had too little experience or have a psychologic block about some formidable formulas. Unfortunately, in their desire to make fluid therapy universally applicable, some leaders in salt and water therapy have been seeking common denominators which are not so common in practice.
791
1ib
• iii
792
FOREWORD TO THE FIRST EDITION
A few of these denominators are agreed on by all, and should be used by all physicians. First, regardless of how accurately fluids are calculated, the best evidence of proper fluid therapy is the patient. Therefore the patient should be carefully watched while fluids are being administered parenterally, and therapy should be adjusted according to the patient's response. Second, the best evidence of degree of hydration in a child is change of weight. Therefore all children receiving parenteral fluids should be weighed daily. Third, physicochemical responses of ions occur in proportion to their equivalents, and not according to gram weights. Therefore serum electrolytes and electrolytes administered should be in terms of milliequivalents (mEq.) or millimols (mM.), not milligrams (mg.). Those reared in an atmosphere of milligrams should convert to the more physiologic ionic milliequivalents: mEq. per liter
mg./IOO ml. X 10 atomic wt.
---'::.-.-----X valence
For a few commonly used ions: ION
VALENCE
Na K
1 1
Cl
1 2
Ca ...................... .
ATOMIC WT.
23 39 36 40
Volumes per cent of carbon dioxide may be converted to millimeters per liter by dividing by 2.2. Further details are discussed by Dr. Bergstrom (p. 795). This is practically the end of the areas of common agreement in therapy. In this volume it will be noted that some authors prescribe fluids on the basis of weight of the patient; others on the basis of surface area; and still others according to the number of calories utilized. Obviously, none is satisfactory, or one system would be universally adopted. The problems involved with all these systems are clearly covered by Dr. Darrow in his clinic (p. 819). Whether salt should be expressed in terms of water in the body or water according to its salt content, each physician can decide. Drs. Metcoff and Crawford have used systems which contain both concepts. Sometimes it seems as if we must stand on our heads to appreciate the more physiologic concept of concentration of water. Dr. Holliday, however, who discusses the physiology of dehydration, uses the more conventional concept of concentration of salt. Each of the authors of the section on Clinical Applications has apologized for "having to include some physiology" in his discussiona real'tribute to pediatricians. Therefore some duplication occurs. Fortunately, this makes for easier reading as each pathologic condition is discussed fully. More information is included in some of the clinical articles than
FOREWORD TO THE FIRST EDITION
793
is indicated in the title. For example, Dr. Kaye includes new data on fat solutions as well as techniques of fluid administration through all portals. Dr. Cooke clearly gives concise information not only of diarrhea and vomiting, but also of tricks of fluid therapy; Drs. Guest and Wallace go far beyond simple fluid therapy; Dr. Gardner answers well the question of how fluid therapy differs in children with infection; and the various aspects of surgical fluids are covered in the two papers of Drs. Colle and Paulsen, and Wolferth and Peskin.... Dr. Harrison discusses the still controversial problem of hyperelectrolytemia, and Dr. Cornfeld discusses a syndrome about which we are hearing less and less. Dr. Bongiovanni has recently written on the "Proper Use of Adrenal Hormonal Drugs," so that he quite aptly tells now what to do if the "hormonal drugs" are used improperly. Dr. Barbero discusses the theoretical as well as the practical aspects of fluid therapy in a troublesome respiratory disease which should be the battleground of fluid therapists; and Dr. Engle advises mainly against fluid therapy in the "fluid therapy of heart failure." Dr. Crawford's article is not only an admirable discussion of fluid therapy, but also an admirable presentation in humility . . . . Dr. Oski mentions briefly some of the possibilities in chemistry at the bedside, and Dr. Mellman puts the reader in the proper psychologic approach for good bloodletting. The Editor would like to note also that Drs. John Reinhold and Howard Rawnsley of the Pepper Laboratories, Hospital of the University of Pennsylvania, gave aid and advice in the preparation of several of the papers included in this volume. From this brief review it is noted that the minor ions are apparently not mentioned. This is not so. So far as data are available on such ions as magnesium and phosphate, these are included where applicable. As these ions attain their proper place in the minds of the "salt and water boys," a new review on fluid therapy will appear.