This study is a single-center retrospective observational study comparing two cohorts of very low birth weight (VLBW, birth weight < 1500 grams) infants who received parenteral nutrition (PN) either before or after a concentrated PN regime was implemented into clinical use. Both PN regimes were based on standardized PN solutions with the possibility to complement with additive nutritional products according to individual assessment by the attending physician. To meet recommended macronutrient intakes, in 2012 a concentrated parenteral nutrition regime was implemented into clinical use at the neonatal intensive care unit in Umeå University hospital, Sweden. However, there is a lack of data on how changes in nutrient intakes affect growth and electrolyte status in preterm infants. Recent studies have demonstrated an increased incidence of hypokalaemia, hypophosphatemia and hypercalcaemia in infants who received enhanced parenteral energy and protein intakes.~This study is a single-center retrospective observational study comparing two cohorts of very low birth weight (VLBW, birth weight < 1500 grams) infants who received parenteral nutrition (PN) either before or after a concentrated PN regime was implemented into clinical use. Both PN regimes were based on standardized PN solutions with the possibility to complement with additive nutritional products according to individual assessment by the attending physician.
A single-center retrospective observational study comparing two cohorts of very low birth weight (VLBW, birth weight < 1500 grams) infants who received parenteral nutrition (PN) either before or after a concentrated PN regime was implemented into clinical use. Primary outcome is weight SDS at 28 days.