Aggressive parenteral nutrition

Abstract

Aggressive parenteral nutrition (PN) after preterm birth is commenced on day one with the aim of matching fetal growth rate and body composition. The aim of aggressive PN is to reduce the incidence and severity of ex-utero growth retardation (EUGR). EUGR is currently common in extremely low birth weight (ELBW) infants and is associated with co-morbidities including developmental delay and adult coronary artery disease. Parenteral amino acids at 1.5 g/kg/day is required to prevent negative nitrogen balance and 3.5 g/kg/day for positive nitrogen balance similar to that in-utero. Randomised controlled trials provide further evidence that an aggressive nutritional regime can minimise the large protein deficit most ELBW babies incur, and reduce the rate of EUGR. Preventing EUGR avoids the risk of catch-up growth and associated long-term health sequelae. Improving energy and protein intakes in week 1 is associated with better developmental outcomes of ELBW infants. For preterm infants, it is recommended that parenteral amino acids solutions with profiles to mimic fetal aminogram, be started on day 1. Provision of adequate non-protein calories is necessary to prevent oxidation and facilitate protein synthesis. Early intravenous lipid is safe and an optimal fat blend should be chosen to improve long-chain polyunsaturated fatty acid (LCPUFA) status, reduce lipid peroxidation and maintain immune function. Nutritional intake by day 5 should be 3-4 g/kg/day protein and ≥∈100 kcal/kg/day. Growth and body composition should be analysed with long-term health and developmental outcomes to guide future nutritional interventions within the preterm period.