The approach appears to compensate more adequately for the nutritional deficit of babies born before seven months of pregnancy.
Babies delivered to term would receive these nutrients via the mother's placenta.
Premature babies fed intravenously are also at increased risk from cholestasis – a form of liver damage that occurs in 10-60% of babies in neonatal intensive care units across Europe and the US.
The high prevalence has been attributed to high doses of amino acids and soybean based lipid emulsions that are used to feed these babies.
Researchers from the Medical University of Vienna’s Department of Pediatrics and Adolescent Medicine undertook a retrospective data analysis of 162 infants born in the study period. These infants were then placed in one of two feeding approaches.
A ‘conservative’ approach involved administering 6-18 grams per kilogram per day (g/kg/d) of glucose, 0.5–4 g/kg/d of protein and 0.5–3.5 g/kg/d of lipids intravenously (parenteral nutrition). These amounts were increased as tolerated by the babies per day.
The approach was supplemented with feeding via a tube (enteral feeding (EF)) in which an extensively hydrolysed formula (eHF) at half strength (10 kcal/oz) was used.
As soon as half EF was tolerated, eHF was advanced to full strength (20 kcal/oz) and switched to preterm formula (24 kcal/oz) as soon as infants reached 1 kg of body weight.
An ‘aggressive’ approach meant babies were given more protein, as well as vitamins, electrolytes, calcium and sugar at an earlier stage.
Babies were fed 7.2 - 18 g/kg/d of glucose, 2 – 4 g/kg/d of protein and 1 – 4 g/kg/d of lipids in an incremental manner as tolerated.
EFs were started with full strength preterm formula (24 kcal/oz) instead of diluted eHF on the first day of life. Clinicians were allowed to perform advancements of EF by a maximum of 20 ml/kg/d.
Enteral feedings for both groups were always started with formula and switched to own mother’s breast milk as soon as available.
Breast milk fortification (140 ml/kg/d (conservative), 100 ml/kg/d (aggressive) was also started earlier in the aggressive approach as soon as EF was reached.
Bigger and fatter babies
Primary outcomes showed that infants fed aggressively weighed more when they were discharged from the hospital (around 2.5 kg vs. 2 kg on average with the conservative approach).
The babies also gained a centimetre more in head circumference and height.
The incidence of PNAC was also significantly lower during the period of aggressive vs. conservative nutrition (27% vs. 46%).
"Previously we have been extremely careful with the feeding of these tiny premature babies, for fear of causing enteritis," said Dr Andreas Repa, paediatrician at the Department of Pediatrics at the Medical University of Vienna in Austria.
"The study shows that the change in best practice is proving to be very successful. These tiny premature babies leave hospital in a more robust state and end up being not much smaller than other children."
The researchers expressed concern about a negative impact of initiating EFs with full strength preterm formula in the aggressive approach.
“Diluted hydrolysed feedings and earlier fortification on the incidence of PNAC, feeding tolerance and necrotising enterocolitis (NEC) are ill-defined,” they commented.
“It was therefore reassuring to find that the incidence of PNAC was even significantly reduced after modifying our feeding regimen.”
Published online ahead of print, doi.org/10.7717/peerj.2483
“Aggressive nutrition in extremely low birth weight infants: impact on parenteral nutrition associated cholestasis and growth.”
Authors: Andreas Repa, Ruth Lochmann, Lukas Unterasinger, Michael Weber, Angelika Berger, Nadja Haiden.