Malnutrition is a common problem in the neonatal intensive care unit. Recent studies
indicate that prematurely born neonates commonly develop a severe nutritional deficit during
the first weeks after birth, referred to as extrauterine growth restriction. Despite an
increase in growth during the second month of hospitalization, many neonates are ultimately
discharged home having grown inadequately. The early nutritional deficit affects weight gain
as well as growth in length and head circumference.
Growth measurements such as weight, length, and head circumference, however, are macroscopic
measures of nutritional status and underestimate the physiologic consequences of prolonged
nutritional deprivation. Energy and micronutrient deficiencies alter growth at a cellular
and tissue level before macroscopic measures are altered. In the brain, for instance, energy
is required for cell division and neuronal growth, glial cell function, and myelination.
Energy deprivation may consequently alter neuronal function and growth, resulting in adverse
Immunocompetence also appears to be sensitive to the untoward effects of energy and
nutritional deficiency. Malnourished neonates often exhibit immune deficiencies related to
inadequate protein intake that compound an already immature immune system. Such
immunodeficiency results in susceptibility to infectious agents that creates substantial
morbidity and mortality to the course of intensive care for premature infants.
A recent study suggests that postnatal malnutrition and growth restriction are inevitable if
current recommended dietary intakes are followed. Multicenter studies show that variation in
dietary intake accounts for 45% of the variation in growth. Hence, efforts have focused on
determining whether nutritional deficiency and the observed growth restriction of premature
infants can be prevented through the use of more optimal nutritional intake. In addition,
inadequate protein support may be a primary cause for growth failure.
Based on animal studies showing high in utero amino acid flux observed during the latter
phase of gestation, Thureen et al have suggested the use of higher doses of amino acid
supplementation in order to minimize growth restriction and improve outcomes of premature
infants. However there are no large human trials that demonstrate that this approach
promotes better growth or that it is safe. While small doses of amino acids may be
inadequate to promote normal growth, high doses may lead to elevated serum amino acid levels
and increase the occurrence of toxicity. Through the implementation of a multicenter,
randomized trial and tandem mass spectrometry, the investigators propose to evaluate the
effects of two distinct strategies of amino acid supplementation on serum amino acid
profiles and growth of premature infants during the first 28 days of life.
- Documentation of informed consent
- Gestational age between 23 weeks and 0/7 days and 29 weeks and 6/7 days
- If subject is transferred to another hospital, the ability to obtain follow-up data
- No major anomalies
- Ability to begin parenteral nutrition within the first 48 hours after birth
- Gestational age < 23 weeks or >= 30 weeks
- Any major congenital anomalies