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The provision of parenteral nutrition (PN) forms part of standard practice in neonatal intensive care units, supporting growth in preterm infants until such time that they can be fully enterally nourished, representing the largest single patient group receiving PN.1 There is a paucity of evidence concerning the recommended micronutrient intake required. Vitamin A plays a vital role in growth and development of many organ systems, and deficiency of vitamin A increases the risk of retinopathy of prematurity and chronic lung disease.2 The current consensus guidelines recommend 700–1500 IU/kg/day of vitamin A.3 Vitlipid N (Fresenius Kabi, Runcorn, UK) provides 920 IU/kg/day of vitamin A. We performed this study aiming to describe vitamin A concentrations in those receiving standard parenteral vitamin A supplementation (920 IU/kg/day) as Vitlipid N.
Neonates requiring PN for >28 days, (January 2009–December 2013) were identified using Badgernet. Those receiving ≥50% of nutritional requirements as PN at 4 weeks were included, as they received the full Vitlipid N dose. No other form of vitamin A supplementation was provided. Serum fat-soluble vitamins (A, D, E) were measured at 4–6 weeks of age. Low serum vitamin A was defined as <200 µg/L (0.7 µmol/L), very low <100 µg/L (0.35 µmol/L). Forty-three preterm infants met inclusion criteria. Median gestational age was 27.3 weeks (range; 23.6–36.2). Low vitamin A n=31 (72%) and very low concentrations n=15 (35%) were recorded at 4–6 weeks. C-reactive protein levels were within normal range at all time points. Twenty-seven (84%) infants ≤1500 g had low vitamin A concentrations, with 15 (47%) recording very low concentrations. In comparison, only 5 (54%) infants >1500 g had low concentrations, with none having very low concentrations. The serum concentrations for other vitamins were within normal range.
Higher doses of vitamin A are associated with improved outcomes in preterm infants2 and Tyson et al4 demonstrated intramuscular doses of 5000 IU were safe and effective in maintaining serum concentration. Our results show that, despite intravenous supplementation of vitamin A in PN using amounts recommended, vitamin A levels continued to be low, particularly in those infants with birth weight ≤1500 g; mirroring much previous work. The limitations to our work are the retrospective cohort analysis, absence of retinol-binding-protein levels and the use of vitamin A plasma concentrations rather than actual tissue levels of vitamin A.
This study has added further weight to evidence that preterm infants at the extreme ends of prematurity are at greatest risk of vitamin A insufficiency, despite adequate parenteral supplementation. It suggests that the current vitamin A dose recommended is inadequate and should be supplemented with oral or intramuscular vitamin A.
Contributors HO: first author, reporting of the work, editor of work, background research into current evidence. CH: data collection. AB: planning or work, editor of written work. FP: planning of work. LVM: data collection, editor of written work. AS: background research of current evidence.
Competing interests None declared.
Provenance and peer review Not commissioned; externally peer reviewed.
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