Optimizing parenteral nutrition to achieve an adequate weight gain according to the current guidelines in preterm infants with birth weight less than 1500 g: a prospective observational study

AIM: European Society for Clinical Nutrition and Metabolism released the guidelines on pediatric parenteral nutrition in 2018. We aimed to compare the parenteral nutrition (PN) regimen with the current guidelines, evaluate weight gain and explore the correlation of parenteral macronutrient and energy intakes with weight gain outcome in preterm infants with birth weight less than 1500 g. METHODS: A prospective observational study was conducted. Parenteral macronutrients and energy intakes were described. Weight gain during PN was assessed. Nutritional factors associated with weight gain outcome after PN were identified using a cox proportional hazards model. RESULTS: A total of 163 infants were included in this study, in which 41 were extremely low birth weight (ELBW) infants and 122 were very low birth weight (VLBW) infants. Average glucose, amino acid, lipid, and energy during the first postnatal week were 7.5 g/kg/d, 2.4 g/kg/d, 0.8 g/kg/d, 48 kcal/kg/d. Median maximum glucose, amino acid, lipid, and energy were 11.1 g/kg/d, 3.5 g/kg/d, 3 g/kg/d, 78 kcal/kg/d. Median days to maximum glucose, amino acid, lipid, and energy were 10, 9, 12, 11 days. The proportion of appropriate for gestational age (AGA) infants was 76.9%. The ratio of infants without poor weight gain outcome after PN was 38%. With every 0.1 g/kg/d decrease of maximum amino acid and average lipid during the first postnatal week, the probability of appropriate weight gain outcome decreased by 77.6 and 74.4% respectively. With each additional day to maximum glucose and energy, the probability of appropriate weight gain outcome decreased by 5.6 and 6.1% respectively. CONCLUSIONS: Most preterm infants with birth weight less than 1500 g remain below the latest recommended nutrition goals. The poor weight gain outcome of these infants after PN is related to insufficient parenteral macronutrient and energy intakes. PN strategies should be improved according to the latest evidence-based recommendations. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s12887-021-02782-1.