Standard formulas and individualised parenteral nutrition preparations in very low birth weight infants

Optimal nutrition in very low birth weight (VLBW) infants is associated with improved clinical outcomes. When parenteral nutrition (PN) with a marketing authorisation is not appropriate, hospital pharmacies can prepare more suitable PN preparation. This corresponds to standard preparations (i.e., available at any time with a fixed composition) or individualised ones (i.e., available after a period of prescription, preparation, and pharmaceutical control). In France, 12 standard formulas to be compounded were proposed by a national consortium in 2018. The objective of the present study was to evaluate whether individualised PN preparations ordered in our hospital are substitutable by one of the 12 standard formulas.

All PN prescriptions for VLBW infants made in 2021 in our hospital were retrospectively extracted. For each prescription, the theoretical intakes that an infant would have received if a standard preparation had been administered were calculated. Standard and individualised preparations were compared using the Mann-Whitney U test for each component. Secondly, the relative difference between the expected intakes and effectively intakes was calculated for each component.

Over the study period, 1708 prescriptions were identified (corresponding to 1708 PN individualised preparations). Most infants were extremely low birth weight infants. Based on the methods of comparison, none of the 12 standard formulas fitted with targeted intakes achieved with individualised PN preparations ordered, whereas prescriptions did fit with international guidelines.

The study highlights how it is difficult to establish nationally standard PN formulas for VLBW infants; the development of local standard formulas seems therefore relevant.