USA Surgery Today

The prematurely born infant receives limited nutrition as a consequence of inadequate caloric delivery and concurrent medical problems. Immaturity of the gastrointestinal tract in premature infants makes provision of optimal nutrition especially difficult. Parenteral nutrition remains the mainstay in the early nutritional management of the premature infant.:Lozol

Current evidence indicates that parenteral nutrition with amino acids and glucose can be safely started within 24 hours of birth. Provision of amino acids at 1.5 g per kg per day, with 35 kcal per kg per day of nonprotein energy, will prevent negative nitrogen balance and is well tolerated by even the most immature and sick neonates (35:Lozol). Lipids, delivered as 20% Intralipid, may be initiated within the first 24 to 48 hours of life (0.5 to 1 g per kg per day) and gradually increased to a maximum of 3 g per kg per day. Protein intake may be increased to 3.5 g per kg per day. Nitrogen retention close to fetal accretion rates may be achieved with caloric intake of 80 to 85 kcal per kg per day and amino acid intake of 3.5 to 4.0 g per kg per day (36:Lozol). Early, optimal delivery of calcium and phosphate is important for the prevention of metabolic bone disease.

Early introduction of enteral “trophic” feeds has been shown to be beneficial and safe in premature infants with the feeding route usually by a nasogastric tube. Breast milk, with its nutritional, antimicrobial, and immunologic properties, is the preferred source of nutrition, unless there is a maternal contraindication. Trophic feeds may be started in the first 48 to 72 hours and advanced gradually to provide full enteral nutrition by the second or third week of life. Human milk does not provide adequate protein, calcium, phosphorus, sodium, trace metals, and vitamins to meet the tissue and bone growth needs of the VLBW neonate (less than 32 to 34 weeks; less than 1,500 to 2,000 g). Powdered and liquid human milk fortifiers are commercially available and provide the nutritional balance needed. Human milk may be fortified once the infant is tolerating 60% to 70% of the feed volume enterally.:Lozol Special formulas for premature infants contain additional protein, easily absorbed lipids (15% to 50% medium-chain triglycerides:Lozol), increased calcium and phosphorus, and trace minerals and vitamins to optimize growth. Improved long-term growth and bone mineral content have been shown in infants fed with premature infant formula rather than formula for term infants.

To meet the continuing needs of the premature infant after discharge from the hospital, formulas are available that provide increased protein, energy, and mineral intake. Their use has resulted in greater linear growth, weight gain, and bone mineralization when compared with term neonatal formula.