Postgraduate Medicine
ISSN: 0032-5481 (Print) 1941-9260 (Online) Journal homepage: http://www.tandfonline.com/loi/ipgm20
Neonatal nutrition Yves W. Brans To cite this article: Yves W. Brans (1976) Neonatal nutrition, Postgraduate Medicine, 60:1, 113-115, DOI: 10.1080/00325481.1976.11714419 To link to this article: http://dx.doi.org/10.1080/00325481.1976.11714419
Published online: 07 Jul 2016.
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Citing articles: 1 View citing articles
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Date: 25 August 2017, At: 22:52
Downloaded by [Australian Catholic University] at 22:52 25 August 2017
• After a promising beginning during the second quarter of this century, perinatal nutritional and metabolic research slowed its pace, either in frustration at the technical complexities of metabolic studies or out of philosophical belief that nature's work should not be tampered with. In the past few years, however, our ability to help very sick and very premature neonates to survive has improved tremendously. Accompanying this improvement was the necessity to accomplish what nature was not programmed to do-provide adequate nutrients to babies prematurely separated from their matemoplacental supply lines or unable to participate effectively in the act of feeding. This necessity entailed a search for various means of bypassing the stomach or the gastrointestinal tract altogether. From experience with varia us modes of feeding and with various nutritive formulas, and from the consequences of their use and misuse, a wealth of information has accumulated. Books, monographs, and articles on the subject abound1 - 3 to the point of biding our lingering ignorance of basic issues. This article makes no attempt to provide recipes for feeding the average baby. lnstead, it tries to place important notions into perspective, to dispel self-perpetuating myths, and to point a fin ger at the hu ge gaps that still mar our knowledge of very basic problems. Fetal Swallowlng and Digestion
A frequent mistaken notion is that birth is a breaking point between two totally different and scarcely related modes of Iife. Indeed, it is only a storm y episode in what should otherwise be a smooth, continuous transition from aquatic to terrestrial life. Pertinent to the continuity of gastrointestinal function is the fact that the fetus is probably not fed exclusively via the placenta! supply line. Swallowing and digestion of amniotic fluid pro teins have been demonstrated in the human fetus. Near term, the fetus swallows daily about 540 ml of amniotic fluid (90 ml, or 3 oz, in each four-hour period). This quantity of amniotic fluid provides from 0.24 to 0.30 gm of protein per kilogram of body weight, representing 10% to 15% of a mature neonate's protein requirements. To what extent other amniotic fluid constituents, such as glucose and fat, are utilized is yet unknown. That this swallowing and digestive function may be important to fetal nutrition is suggested by the frequency of intrauterine growth retardation among fetuses who cannat swallow because of gastrointestinal obstruction or neurologie damage . .,.
Vol. 60 •
No. 1 • July 1976 • POSTQRADUATE MEDICINE
neonatal nutrition an overview Yves W. Brans, MD Pritzker School of Medicine University of Chicago
consider When should the first feeding occur? When is transfer to a perinatal intensive care center indicated? What should be done for the neonate who has insufficient strength to suck or becomes tired before reaching satiety?
113
Yves W. Brans Dr. Brans is director, neonatal research laboratory, and assistant professer, department of pediatries, Pritzker School of Medicine, University of Chicago.
Downloaded by [Australian Catholic University] at 22:52 25 August 2017
Basic Principles of Feedlng
Whenever feeding is being discussed, three questions immediately come to mind: When? What? How? More basic than any of these questions is that of end point: What constitutes for the clinician a sign of optimal nutrition? The obvious answer is an appropriate rate of weight gain, ie, a rate that allows the baby's weight to remain at least on the growth curve being achieved in utero, and preferably on the 50th percentile line. This definition does not take into consideration the quality of weight gain. The infant of a diabetic mother or a hydropic neonate may be larger and heavier than average, but the excess is due to fat in the former case and water in the latter. No good studies of body composition have been performed on these babies, but anecdotal data suggest that they are actually deficient in body proteins. Neonates whose intrauterine growth was retarded not only are smaller at term than their normal gestational peers but also have an excess of water and a lack of proteins. Fin ally, sorne feeding techniques or formulas produce water retention instead of (or in addition to) tissue accretion and may appear ''better'' to the casual observer bec ause they result in faster rates of weight gain. A more appropriate end point would be the rate of tissue accretion, but the measurement of this parameter must await the development of readily available, noninvasive techniques. Normal mature babies learn to regulate their own nutritional intake soon after birth, voicing hunger loudly and sucking to satiety if left to their own deviees. These babies thus serve to illustrate sorne of the basic principles of feeding. When to feed-It is customary in our society to allow babies a resting or fasting period of a few hours, during which they presumably recover from the shock of birth. The logic of such a practice is questionable. In developing
114
countries, neonates are commonly found sucking the breast half an hour after delivery without suffering any harm. Neonates who tend to become hypoglycemie, such as infants of diabetic mothers or babies asphyxiated at birth, are often fed within the first four hours after birth without major problems. The practice of waiting a "magic" eight hours before initiating feedings should be seriously reevaluated. Early feedings reduce wastage offat and glycogen reserves and li mit the rise of serum bilirubin, presumably by reducing the enterohepatic reabsorption of bilirubin. Intestinal motility is decreased in the fasting neonate, and conjugated bilirubin excreted with biliary fluids stagnates in the intestinal lumen. This gives bacterial flora and enzymes greater opportunity to unconjugale bilirubin. Unconjugated bilirubin is theo reabsorbed into the bloodstream and contributes to overloading an immature liver. What to feed- This is more important than when to feed. The main concem at the time of the first feeding is to avoid regurgitation and aspiration pneumonia. The first step should al ways be to test the neonate 's pharyngeal coordination and patency of the upper gastrointestinal tract. The use of 5% or 10% dextrose in water for this purpose remains much too common. Experiments with rabbits have demonstrated that dextrose and milk formulas have similar irritating effects on the bronchoalveolar epithelia and that sterile water is less damaging. The first feeding, therefore, should always be with sterile water. Isotonie saline would probably be preferable physiologically, as the bronchial tree has been exposed to amniotic fluid throughout fetal life, but it is not very palatable. Beginning with the second feeding, breast milk or artificial formula may be used. There is no need to start with dilute formula and gradually increase the concentration. The standard dilution of 20 calories/oz is weil tolerated from the beginning. The value of higher concentrations for normal mature bahies is doubtful when they are fed ad lib. Infants will usually compensate for the higher concentration by reducing volume intake. How to F eed-I shaH not enter here into the controversy of breast milk versus formula feeding. Breast milk may have immunologie and digestive properties which might be advantageous under special circumstances. The higher morbidity and mortality observed in infants fed artificial formulas, however, were
POSTGRADUATE MEDICINE o July 1976 o Vol. 60
o
No. 1
either reported before 1940, when adequate refrigeration facilities were not available to ali households, or in developing countries where poor hygiene was a primary factor in contamination.
Downloaded by [Australian Catholic University] at 22:52 25 August 2017
Special Problems
Large, low-birth-weight infants-If such infants are doing well-and if they have matured beyond 33 weeks' gestation or weighed more than 1,500 gm at birth or both-they usually have little more difficulty in feeding than the normal mature neonate. However, they require doser supervision. Early feedings are especially important to these infants bec a use they have fewer metabolic reserves. Feeding should be attempted with great care in order to avoid aspiration pneumonia. The use of a more concentrated formula (up to 30 calories/oz) may be considered for a baby whose gastric capacity is limited, keeping in mind that proper evaluation of such formulas is still incomplete. Small, frequent feedings may be better tolerated than large feedings every three or four hours, but the optimal timing should be determined by measuring gas tric emptying ti me. An oro gastric tube-and not a nasogastric tube, which partially ocdudes the nares of a baby whose breathing capacity may be compromisedmay be required if the neonate does not have sufficient strength to suck or becomes tired be fore reaching satiety. Tin y preterm or ill neonates-Tin y preterm neonates or larger infants who are too ill to feed properly obviously cause concem. That we have yet to devise the optimal feeding technique for these neonates is indicated by their disproportionately large Joss of birth weight within the first postnatal days, the sometimes considerable Iapse of time before they regain their birth weight, and the persisting deviation from their intrauterine growth curve in postnatal life ("extrauterine growth retardation' '). The problem is complicated by many factors, induding our lack of knowledge re garding precise calorie and nutritive requirements, the extreme metabolic lability of the tiny neonate, and our inability to provide easily even minimal calorie requirements for se veral days or weeks after birth. The first of these problems has recently been discussed at length, 3 and the second is discussed in another portion of this symposium.* Attempts to re*See Dweck. p 118.
Vol. 60 • No. 1 • July 1976 • POSTGRADUATE MEDICINE
solve the third problem may include the use of special formulas enriched with medium-chain triglycerides, which increase calorie content without increasing osmolality. or the use of parenteral alternatives such as transpyloric feedings or supplementation with infusates of dextrose and amino acid. A recent promising approach is the addition of soybean lipids to parenteral infusates. Above ali, meticulous monitoring of metabolic parameters is essential. Whenever special techniques need to be used, the infant should be placed in a center capable of providing special care around the dock. Inability to provide adequate nutrition should be a major indication for transferring a neonate to the nearest perinatal intensive care center. Summary
Sorne everyday practices in infant feeding, such as waiting eight hours after birth, have no logical or scientific foundation and their value should be reassessed. The first feeding should al ways be with sterile water because it is Jess irritating to bronchoalveolar epithelia than are dextrose solutions. Large, low-birth-weight infants present few feeding problems but require doser supervision than normal mature neonates. Optimal feeding techniques have not yet been devised for tiny preterm or ill neonates. Application of special techniques to provide these infants with even minimal calorie requirements for severa! days or weeks after birth should only be attempted in centers capable of providing special, around-theclock care and meticulous monitoring of metabolic parameters. • Address reprint requests to Yves W. Brans. MD. Department of Pediatries. 5825 Maryland Ave. Chicago. IL 60637. ReadySource on neon a tai problems appears on page 135. CME Credit Quiz on neonatal problems be gins on page 135.
References 1. Barness LA, Pitkin RM: Symposium on nutrition. Clin Perinatol 2:309-352, 373-417. 1975 2. Brans YW. Cassady G: Fetal nutrition and body composition. In Ghadimi H (Editor): Total Parenteral Nutrition: Premises and Promises. New York. John Wiley & Sons, Inc. 1975. pp 301-333 3. Dweck HS: Feeding the prematurely born infant: Fluids. calories. and methods of feeding during the period of extrauterine growth retardation. Clin Perinato12: 183-202, 1975
115
ISSN: 0032-5481 (Print) 1941-9260 (Online) Journal homepage: http://www.tandfonline.com/loi/ipgm20
Neonatal nutrition Yves W. Brans To cite this article: Yves W. Brans (1976) Neonatal nutrition, Postgraduate Medicine, 60:1, 113-115, DOI: 10.1080/00325481.1976.11714419 To link to this article: http://dx.doi.org/10.1080/00325481.1976.11714419
Published online: 07 Jul 2016.
Submit your article to this journal
View related articles
Citing articles: 1 View citing articles
Full Terms & Conditions of access and use can be found at http://www.tandfonline.com/action/journalInformation?journalCode=ipgm20 Download by: [Australian Catholic University]
Date: 25 August 2017, At: 22:52
Downloaded by [Australian Catholic University] at 22:52 25 August 2017
• After a promising beginning during the second quarter of this century, perinatal nutritional and metabolic research slowed its pace, either in frustration at the technical complexities of metabolic studies or out of philosophical belief that nature's work should not be tampered with. In the past few years, however, our ability to help very sick and very premature neonates to survive has improved tremendously. Accompanying this improvement was the necessity to accomplish what nature was not programmed to do-provide adequate nutrients to babies prematurely separated from their matemoplacental supply lines or unable to participate effectively in the act of feeding. This necessity entailed a search for various means of bypassing the stomach or the gastrointestinal tract altogether. From experience with varia us modes of feeding and with various nutritive formulas, and from the consequences of their use and misuse, a wealth of information has accumulated. Books, monographs, and articles on the subject abound1 - 3 to the point of biding our lingering ignorance of basic issues. This article makes no attempt to provide recipes for feeding the average baby. lnstead, it tries to place important notions into perspective, to dispel self-perpetuating myths, and to point a fin ger at the hu ge gaps that still mar our knowledge of very basic problems. Fetal Swallowlng and Digestion
A frequent mistaken notion is that birth is a breaking point between two totally different and scarcely related modes of Iife. Indeed, it is only a storm y episode in what should otherwise be a smooth, continuous transition from aquatic to terrestrial life. Pertinent to the continuity of gastrointestinal function is the fact that the fetus is probably not fed exclusively via the placenta! supply line. Swallowing and digestion of amniotic fluid pro teins have been demonstrated in the human fetus. Near term, the fetus swallows daily about 540 ml of amniotic fluid (90 ml, or 3 oz, in each four-hour period). This quantity of amniotic fluid provides from 0.24 to 0.30 gm of protein per kilogram of body weight, representing 10% to 15% of a mature neonate's protein requirements. To what extent other amniotic fluid constituents, such as glucose and fat, are utilized is yet unknown. That this swallowing and digestive function may be important to fetal nutrition is suggested by the frequency of intrauterine growth retardation among fetuses who cannat swallow because of gastrointestinal obstruction or neurologie damage . .,.
Vol. 60 •
No. 1 • July 1976 • POSTQRADUATE MEDICINE
neonatal nutrition an overview Yves W. Brans, MD Pritzker School of Medicine University of Chicago
consider When should the first feeding occur? When is transfer to a perinatal intensive care center indicated? What should be done for the neonate who has insufficient strength to suck or becomes tired before reaching satiety?
113
Yves W. Brans Dr. Brans is director, neonatal research laboratory, and assistant professer, department of pediatries, Pritzker School of Medicine, University of Chicago.
Downloaded by [Australian Catholic University] at 22:52 25 August 2017
Basic Principles of Feedlng
Whenever feeding is being discussed, three questions immediately come to mind: When? What? How? More basic than any of these questions is that of end point: What constitutes for the clinician a sign of optimal nutrition? The obvious answer is an appropriate rate of weight gain, ie, a rate that allows the baby's weight to remain at least on the growth curve being achieved in utero, and preferably on the 50th percentile line. This definition does not take into consideration the quality of weight gain. The infant of a diabetic mother or a hydropic neonate may be larger and heavier than average, but the excess is due to fat in the former case and water in the latter. No good studies of body composition have been performed on these babies, but anecdotal data suggest that they are actually deficient in body proteins. Neonates whose intrauterine growth was retarded not only are smaller at term than their normal gestational peers but also have an excess of water and a lack of proteins. Fin ally, sorne feeding techniques or formulas produce water retention instead of (or in addition to) tissue accretion and may appear ''better'' to the casual observer bec ause they result in faster rates of weight gain. A more appropriate end point would be the rate of tissue accretion, but the measurement of this parameter must await the development of readily available, noninvasive techniques. Normal mature babies learn to regulate their own nutritional intake soon after birth, voicing hunger loudly and sucking to satiety if left to their own deviees. These babies thus serve to illustrate sorne of the basic principles of feeding. When to feed-It is customary in our society to allow babies a resting or fasting period of a few hours, during which they presumably recover from the shock of birth. The logic of such a practice is questionable. In developing
114
countries, neonates are commonly found sucking the breast half an hour after delivery without suffering any harm. Neonates who tend to become hypoglycemie, such as infants of diabetic mothers or babies asphyxiated at birth, are often fed within the first four hours after birth without major problems. The practice of waiting a "magic" eight hours before initiating feedings should be seriously reevaluated. Early feedings reduce wastage offat and glycogen reserves and li mit the rise of serum bilirubin, presumably by reducing the enterohepatic reabsorption of bilirubin. Intestinal motility is decreased in the fasting neonate, and conjugated bilirubin excreted with biliary fluids stagnates in the intestinal lumen. This gives bacterial flora and enzymes greater opportunity to unconjugale bilirubin. Unconjugated bilirubin is theo reabsorbed into the bloodstream and contributes to overloading an immature liver. What to feed- This is more important than when to feed. The main concem at the time of the first feeding is to avoid regurgitation and aspiration pneumonia. The first step should al ways be to test the neonate 's pharyngeal coordination and patency of the upper gastrointestinal tract. The use of 5% or 10% dextrose in water for this purpose remains much too common. Experiments with rabbits have demonstrated that dextrose and milk formulas have similar irritating effects on the bronchoalveolar epithelia and that sterile water is less damaging. The first feeding, therefore, should always be with sterile water. Isotonie saline would probably be preferable physiologically, as the bronchial tree has been exposed to amniotic fluid throughout fetal life, but it is not very palatable. Beginning with the second feeding, breast milk or artificial formula may be used. There is no need to start with dilute formula and gradually increase the concentration. The standard dilution of 20 calories/oz is weil tolerated from the beginning. The value of higher concentrations for normal mature bahies is doubtful when they are fed ad lib. Infants will usually compensate for the higher concentration by reducing volume intake. How to F eed-I shaH not enter here into the controversy of breast milk versus formula feeding. Breast milk may have immunologie and digestive properties which might be advantageous under special circumstances. The higher morbidity and mortality observed in infants fed artificial formulas, however, were
POSTGRADUATE MEDICINE o July 1976 o Vol. 60
o
No. 1
either reported before 1940, when adequate refrigeration facilities were not available to ali households, or in developing countries where poor hygiene was a primary factor in contamination.
Downloaded by [Australian Catholic University] at 22:52 25 August 2017
Special Problems
Large, low-birth-weight infants-If such infants are doing well-and if they have matured beyond 33 weeks' gestation or weighed more than 1,500 gm at birth or both-they usually have little more difficulty in feeding than the normal mature neonate. However, they require doser supervision. Early feedings are especially important to these infants bec a use they have fewer metabolic reserves. Feeding should be attempted with great care in order to avoid aspiration pneumonia. The use of a more concentrated formula (up to 30 calories/oz) may be considered for a baby whose gastric capacity is limited, keeping in mind that proper evaluation of such formulas is still incomplete. Small, frequent feedings may be better tolerated than large feedings every three or four hours, but the optimal timing should be determined by measuring gas tric emptying ti me. An oro gastric tube-and not a nasogastric tube, which partially ocdudes the nares of a baby whose breathing capacity may be compromisedmay be required if the neonate does not have sufficient strength to suck or becomes tired be fore reaching satiety. Tin y preterm or ill neonates-Tin y preterm neonates or larger infants who are too ill to feed properly obviously cause concem. That we have yet to devise the optimal feeding technique for these neonates is indicated by their disproportionately large Joss of birth weight within the first postnatal days, the sometimes considerable Iapse of time before they regain their birth weight, and the persisting deviation from their intrauterine growth curve in postnatal life ("extrauterine growth retardation' '). The problem is complicated by many factors, induding our lack of knowledge re garding precise calorie and nutritive requirements, the extreme metabolic lability of the tiny neonate, and our inability to provide easily even minimal calorie requirements for se veral days or weeks after birth. The first of these problems has recently been discussed at length, 3 and the second is discussed in another portion of this symposium.* Attempts to re*See Dweck. p 118.
Vol. 60 • No. 1 • July 1976 • POSTGRADUATE MEDICINE
solve the third problem may include the use of special formulas enriched with medium-chain triglycerides, which increase calorie content without increasing osmolality. or the use of parenteral alternatives such as transpyloric feedings or supplementation with infusates of dextrose and amino acid. A recent promising approach is the addition of soybean lipids to parenteral infusates. Above ali, meticulous monitoring of metabolic parameters is essential. Whenever special techniques need to be used, the infant should be placed in a center capable of providing special care around the dock. Inability to provide adequate nutrition should be a major indication for transferring a neonate to the nearest perinatal intensive care center. Summary
Sorne everyday practices in infant feeding, such as waiting eight hours after birth, have no logical or scientific foundation and their value should be reassessed. The first feeding should al ways be with sterile water because it is Jess irritating to bronchoalveolar epithelia than are dextrose solutions. Large, low-birth-weight infants present few feeding problems but require doser supervision than normal mature neonates. Optimal feeding techniques have not yet been devised for tiny preterm or ill neonates. Application of special techniques to provide these infants with even minimal calorie requirements for severa! days or weeks after birth should only be attempted in centers capable of providing special, around-theclock care and meticulous monitoring of metabolic parameters. • Address reprint requests to Yves W. Brans. MD. Department of Pediatries. 5825 Maryland Ave. Chicago. IL 60637. ReadySource on neon a tai problems appears on page 135. CME Credit Quiz on neonatal problems be gins on page 135.
References 1. Barness LA, Pitkin RM: Symposium on nutrition. Clin Perinatol 2:309-352, 373-417. 1975 2. Brans YW. Cassady G: Fetal nutrition and body composition. In Ghadimi H (Editor): Total Parenteral Nutrition: Premises and Promises. New York. John Wiley & Sons, Inc. 1975. pp 301-333 3. Dweck HS: Feeding the prematurely born infant: Fluids. calories. and methods of feeding during the period of extrauterine growth retardation. Clin Perinato12: 183-202, 1975
115
