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Supplement

Introduction¹

Department of Pediatrics, McMaster University, Hamilton, Ontario, Canada L8N 3Z5, and ^* Children’s Nutrition Research Center and Department of Pediatrics, Baylor College of Medicine and Texas Children’s Hospital, Houston, TX 77030

²To whom correspondence should be addressed at McMaster University, Department of Pediatrics, 1200 Main Street West, Hamilton, Ontario, Canada L8N325. E-mail: satkins{at}fhs.csu.mcmaster.ca.

	INTRODUCTION

TOP INTRODUCTION

 
In the pediatric population, disorders of chronic pulmonary insufficiency include bronchopulmonary dysplasia in prematurely born infants, and asthma, cystic fibrosis and congenital heart and lung disorders in both infants and children. Although first-line therapy usually relies on drug interventions such as steroids, evidence is emerging that optimal nutrition plays an important role in the prevention and/or treatment of such disorders. Nutritional status is often compromised in infants and children with pulmonary insufficiency because of greater utilization of nutrients such as energy to compensate for the extra work of breathing or dyspnea. Other nutrients such as vitamin A may be required in amounts greater than age-related dietary reference intakes, to influence reepithelialization of the lining of the respiratory tract. Emerging evidence also suggests a role for exogenously delivered antioxidants, to prevent or ameliorate oxidative stress that may be a causative factor in lung disease. This symposium explored current evidence to support a rationale for special nutritional needs imposed by pulmonary insufficiency disorders in infants and children.

In the first instance, it must be appreciated that a less-than-optimal nutritional status is common in infants and children with pulmonary disorders and that the nutritional deficits are multifactorial in origin. Restricted tolerance of fluid intake, elevated nutrient (especially energy) utilization, prematurity, oxidative stress resulting from oxygen therapy and the need for catch-up growth (velocity of growth greater than normal for age) are clinical problems associated with pulmonary disorders that may impact on nutritional needs. The review by Abrams delineates the etiologies of growth and developmental abnormalities specific to disorders of chronic pulmonary insufficiency that most commonly affect children. Because of the severity of the clinical disorders and the usual extended duration of time until remission occurs, growth is often severely interrupted. Aggressive nutritional therapy may be required in such children, to have their growth return to a normal trajectory and to prevent feeding difficulties such as dysmotility or poor oral feeding.

Because of the severity of the nutritional insults associated with pulmonary disorders in infants and children, preventative interventions or at least attenuation of the lung damage are reasonable approaches. Welty’s review outlines the current issues related to oxidative stress as a causative factor in the development of bronchopulmonary dysplasia, and potential therapeutic strategies to prevent oxidative damage to lung tissue. While current research does not support evidence-based nutritional prescriptions, data are available upon which to base sound hypotheses to be tested in clinical trials.

In growing infants and children with chronic pulmonary insufficiency, energy needs may be elevated to support an increased utilization of energy that results from work of breathing, and/or to promote catch-up growth in those who have suffered growth restriction because of prematurity or chronic disease. Despite studies on energy expenditure in infants over more than two decades, there is not a consensus on either the composition or magnitude of dietary energy required as part of therapy for pulmonary disorders. As outlined in the report by Denne, technical advances in the measurement of energy expenditure using stable isotopes of doubly labeled water and mass spectrometry offer new opportunities to achieve a more accurate assessment of energy needs in infants and children under a variety of conditions including ventilation and while in a free-living environment. Evidence is accumulating that premature infants with chronic lung disease or bronchopulmonary dysplasia have greater energy expenditure than infants with severe lung disease, as do infants of extreme low birth weight who are not ill. Further research designed to examine the variables that influence energy expenditure in growing infants and children will be needed before accurate estimates of energy requirements for these special populations can be derived.

In premature infants growth restriction in early life is related to a multitude of factors including extreme malnutrition at birth resulting from lack of nutrient stores, inability to tolerate adequate nutrition while medically unstable and increased needs. The influence of these factors on growth is compounded when the infant is treated with dexamethasone, a potent steroid that is often used in clinical practice for the purpose of improving pulmonary compliance. As discussed in the review by Atkinson, exogenous dexamethasone interrupts growth processes through interference with the growth hormone/insulin-like growth factor-1 axis and protein turnover. Nutritional rehabilitation during the recovery phase from steroid therapy, when the infants’ lung compliance was stable, was studied by Atkinson and her colleagues. Nutrient-enriched formula fed from the time of discharge from hospital to 3-mo corrected age imparted a positive benefit to growth and body composition in infants recovering from bronchopulmonary dysplasia. However, the observed benefit in early life was not sustained out to 1-y corrected age once the infants had been weaned to a standard diet.

The disease process and limitations imposed by pulmonary diseases on ingesting a normal diet together contribute to the growth failure and feeding and developmental problems that are observed in such populations. Clearly, more studies are required before there is sufficient evidence upon which to derive the specific amounts and composition of nutrients required to promote optimal nutritional status and growth in infants and children stricken with chronic pulmonary insufficiencies.

	FOOTNOTES

 
¹ Presented at the symposium entitled "Pediatric Pulmonary Insufficiency: Nutritional Strategies for Prevention and Treatment" as part of the Experimental Biology 2000 meeting held in San Diego, CA on April 15–18, 2000. This symposium was sponsored by the American Society for Clinical Nutrition and was supported in part by an educational grant from Nestle Nutritionals (USA and Canada). The proceedings of this symposium are published as a supplement to The Journal of Nutrition. Guest editors for this supplement publication were Stephanie A. Atkinson, McMaster University, Hamilton, Canada and Steven A. Abrams, Baylor College of Medicine and Texas Children’s Hospital, Houston, TX.

This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Atkinson, S. A. Articles by Abrams, S. A. Search for Related Content PubMed PubMed Citation Articles by Atkinson, S. A. Articles by Abrams, S. A.