Respiratory Metabolism in Infancy and in Childhood

Abstract

The importance of water in the preservation of health and in the treatment of disease in infancy and in childhood has been recognized for many years. The infantile organism is especially hydrolabile, probably because of its high content of body water; this content comprises over 70 per cent in the newly born infant, as against less than 60 per cent in the adult. This hydrolabile tendency is exemplified by the wide fluctuations in daily body weight of healthy infants while on constant diets, by the ready development of dehydration fever in newly born and in older infants temporarily deprived of water and by the occurrence of anhydremia as a frequent accompaniment of infantile diarrhea.Despite the importance of water to infants, knowledge of their fluid requirements has in large measure been deduced from measurements of the average amounts of milk voluntarily withdrawn from the breast by nursing infants. These observations were later supplemented by studies of water balance, which for the most part were incomplete, since all sources of incoming and outgoing water were not directly determined. The validity of the assumption that the value for fluid intake obtained in these incomplete studies represents the optimal fluid intake for all normal infants can be assessed more accurately through continuous and complete studies of the water exchange throughout the twenty-four hours under varying conditions of diet and environment. This paper presents the results of 28 such measurements of the water exchange of 16 healthy infants. Seven observations on 3 of the infants were made in conjunction with previously reported twenty-The early observations were made in collaboration with Dr. Improved Method for the Determination of Water Balance, ibid. 10:723 (Oct.) 1931. 4. The constants of Newburgh 3 were used to calculate the water of oxidation. One gram of protein, of fat and of carbohydrate when oxidized in the body releases as end products 0.41, 1.07 and 0.60 Gm. of water, respectively. The composition of the metabolic mixture of 3 infants (H. S., J. F. and J. C.) was determined directly in the respiration chamber on the final day of each of 7 observations (17 through 23). In the remaining observations, the daily metabolic mixture was calculated from the energy exchange measured for periods of from two to four hours, the dietary carbohydrate, the urinary nitrogen and the daily behavior records of the infants.1 5. The water loss through skin and lungs was determined from the total insensible perspiration by deducting the difference between exhaled carbon dioxide and inhaled oxygen. CO2\p=m-\O2 was considered to equal 0.41 C + 0.08 P \p=m-\0.08F, when C, P and F represent the grams of carbohydrate, protein and fat, respectively, in the metabolic mixture.3 Downloaded From: http://archpedi.jamanetwork.com/ by a Oakland University User on 06/15/2015