Outcomes Following Early Parenteral Nutrition Use in Preterm Neonates

Premature birth abruptly ends the transplacental transmission of nutrients that allows normal foetal growth and development. Providing adequate nutrition is essential to allow premature babies to continue to grow and mature. Very preterm infants often have difficulty tolerating adequate volumes of milk feeds shortly after birth and so are given supplemental parenteral nutrition (PN). Preterm babies are among the highest PN users of all NHS patients. It has been estimated that PN is received by around 70% of neonatal unit admissions but it is not known exactly which babies receive PN. In addition, how PN affects outcomes has never been tested in a large scale, randomized, placebo controlled neonatal trial.

It is known that PN carries well established risks, of which the most serious and the most common is sepsis with estimates of risk ratios varying from 2.2 to 14.6. In addition there is a growing body of evidence that use of PN within the first seven days of admission to an intensive care unit is associated with worse outcomes in critically unwell adults and children. A subgroup analysis of the paediatric intensive care unit population focusing on neonates showed an increase in infections with early PN use. This suggests that uncertainty exists over the benefit of giving neonates PN in the early postnatal period. It is generally accepted that PN is beneficial to extremely preterm neonates, but in moderately preterm neonates the effect that PN use has on neonatal survival has never been conclusively demonstrated.

The uncertainty over how PN use affects neonatal outcomes is reflected by the wide variety in how PN is used in different units with large variation in use, timing and composition of PN. This is, in part, due to the lack of clear evidence of how PN affects neonatal outcomes like growth and survival. Neonates are also vulnerable to unanticipated treatment effects which can occur in different organ systems and so it is important to show that PN is not detrimental to important neonatal outcomes.

The postmenstrual age at which the nutritional benefits of PN outweigh the risks in moderately preterm babies (30-33 weeks postmenstrual age) is unknown. It is therefore unsurprising that their nutritional management is very variable. In moderately preterm neonates in 2012 and 2013 across England, Scotland and Wales PN was given to 45% of neonates, suggesting clinician equipoise around the balance of benefit to risk. Identifying whether moderately preterm neonates benefit from PN would have important implications for practice in the UK. This work will provide information to guide practice and inform future research.

In summary, PN is widely used in neonates but it is not known exactly how it is used in the UK. It is known to have risks and benefits but there is insufficient evidence to guide practice in moderately preterm neonates.

Study objectives:

• To describe the use of PN in neonatal units across England, Scotland and Wales.
• To identify if use of PN in the first seven postnatal days affects survival in neonates born between 30 and 33 weeks postmenstrual age.
• To explore how PN use in the first seven postnatal days affects other important neonatal outcomes in neonates born between 30 and 33 weeks postmenstrual age.

Study design:

Project A: an epidemiological survey of practice using the National Neonatal Research Database (NNRD).

Project B: a retrospective cohort study of matched groups of babies using data held in the NNRD.

Inclusion criteria

Project A:

• Must be born between 1st January 2012 and 31st December 2017
• Must be admitted to a National Health Service (NHS) neonatal unit in England, Scotland or Wales

Project B:

• Must be born between 30 and 33 weeks postmenstrual age
• Must be born between 1st January 2012 and 31st December 2017
• Must be admitted to an NHS neonatal unit in England, Scotland or Wales

Exclusion criteria

Project A:

No exclusion criteria.

Project B:

• Major congenital gastrointestinal malformations
• Life limiting conditions
• Congenital conditions requiring surgery in the neonatal period
• Missing key background data (birthweight, sex or gestational age)
• Missing data for the primary outcome