Lipid peroxidation assessment by malondialdehyde measurement in parenteral nutrition solutions for newborn infants: a pilot study.

Aim: To determine malondialdehyde (MDA) concentrations in parenteral nutrition admixtures exposed to ambient room light, and in the serum of neonates.

Methods: Using a new method to measure MDA specifically, this study analysed MDA of lipid-containing all-in-one admixtures provided by the pharmacy, with a composition identical to that used in routine clinical conditions. First, 12 admixtures were exposed to ambient light for 24 h, in the neonatal intensive care unit. Secondly, 18 solutions were either exposed to (n = 9) or protected from ambient light (n = 9) during the same period. Samples of admixtures were collected at baseline and 24 h later, for MDA measurement. Serum MDA was also randomly measured in orally fed healthy neonates.

Results: After 24 h exposure to ambient room light, MDA concentrations in parenteral nutrition admixtures increased from 179 (129, 348) nmol l(-1) to 5800 (1632, 14679) nmol l(-1) (p = 0.0002) [50th (10th, 90th) centiles]. When admixtures were protected from light, the increase in MDA was significantly lower than without protection: 187 (60, 429)nmol l(-1) versus 13 696 (3472, 26 049)nmol l(-1) (p = 0.0003). In 54 infants with a gestational age of 33 (28, 39) wk and a birthweight of 1750 (960, 3388) g, plasma MDA concentrations were 173 (98, 315) nmol l(-1).

Conclusion: In solutions protected from light, MDA concentrations were low and were close to the serum MDA concentrations observed in orally fed neonates. Administration of all-in-one admixtures containing lipids in ambient lighting results in intravenous infusion of high levels of MDA which may present an additional source of morbidity in immature infants. This study confirms the need to protect parenteral admixtures from light.