Extrauterine Growth Restriction: What Is the Evidence for Better Nutritional Practices in the Neonatal Intensive Care Unit?



NAINR. 2014;14(3):92-98. 

In This Article

Early Aggressive Nutrition

The American Academy of Pediatrics (AAP) Committee on Nutrition stated in 1985 that optimal nutrition is critical in the management of premature infants and even though the exact goal for nutrition is unknown, postnatal growth should mimic the intrauterine growth of a normal fetus with the same postconceptual age.[13] The 1985 AAP policy statement and Ziegler's et al.'s 1976 paper that defined intrauterine nutrient accretion rates are considered to be the gold standard for neonatal nutrition.[14] Furthermore, they serve as the foundation for the concept of early aggressive nutrition in premature infants.

Early aggressive nutrition is a nutritional approach aimed at preventing the catabolic state that occurs during the first few days after birth in a small premature infant.[15] This approach involves the administration of: 1) total parenteral nutrition (TPN) with a high level of amino acids, usually 3–4 g kg−1 day−1 within hours of birth, 2) Intralipids within the first 24 hours of life usually at 0.5–1 g kg−1 day−1 with advancement to 3 g kg−1 day−1, and 3) Minimal enteral feedings at 10–20 ml kg−1 day−1 are initiated within the first 1–2 days of life.

To date only three randomized controlled trials (RCT) have been conducted to study the effects of early aggressive nutrition in small premature infants. Wilson et al. studied 125 VLBW infants who were randomized to receive a glucose only regimen with amino acids and intralipids being added at 3 days of age and enteral feedings were started once the infant was deemed stable (control group) or TPN with amino acids and intralipids started at 12 hours of life and 48 hours of life, respectively along with enteral feedings being started at 24 hours of life (intervention group). Infants in the intervention group had significantly higher energy intake, took less time to regain their birth weight, and had a significant improvement in weight gain and linear growth at hospital discharge.[16]

Ibrahim and colleagues studied 32 ventilator dependent preterm infants with birth weight < 1250 g and a gestational age between 24 and 32 weeks who were randomized to the control or intervention group.[17] The control group received a similar nutritional regimen as described in a study by Wilson et al.[16] The intervention group received TPN with 3.5 g kg−1 day−1 of amino acids and 3 g kg−1 day−1 of intralipids started within 1 hour of birth. Infants who received the early TPN were shown to have significantly higher energy intake in comparison to the control group and showed positive nitrogen balance throughout the study.

A more recent study by Morgan and associates randomized 150 very preterm infants to receive a control TPN (10% glucose, 2.8 g kg−1 day−1 of protein and intralipids) or to receive a standardized solution, concentrated with added macronutrients parenteral (SCAMP) nutrition regimen (12% glucose, 3.8 g kg−1 day−1 of protein and intralipids). Each group received their TPN within 6 hours of birth. Infants in the SCAMP group had a significant improvement in head circumference at 28 days of age, which the authors report is still apparent at 36 weeks corrected gestational age.[18] Evidence from these RCTs strongly suggest that early aggressive nutrition is safe and results in higher protein and energy intake leading to a positive nitrogen balance, which promotes early and late postnatal growth in small premature infants.