448 - Bilirubin isomers during phototherapy of neonates with hyperbilirubinemia - blue-green light (≈478 nm) versus blue light (≈459 nm)

Poster Number: 448
Publication Number: 448.1082

Background: The clinical part of this randomized controlled trial concerning phototherapy of hyperbilirubinemic neonates showed that blue-green LED light (≈478 nm) was 31 % more efficient than standard blue LED light (≈459 nm), measured by decline of total serum bilirubin. Blue-green LED light (≈475-480 nm) is recommended by the American Academy of Pediatrics (AAP).

Objective: The objective of this part of the trial was to compare the serum bilirubin isomers using the above mentioned two light sources.

Design/Methods: The trial was performed at Aalborg University Hospital, Aalborg, Denmark between March 1 2017 and July 31 2018. The inclusion criteria were: neonates healthy except for hyperbilirubinemia, gestational age ≥33 weeks, birth weight ≥1800 g and postnatal age ˃24 hours. 42 neonates were randomized to receive overhead blue-green LED light and 44 neonates overhead blue LED light. The neonates were treated for 24 hours. The light irradiance were equal, 9.2 x 10^15 and 9.0 x 10^15 photons/cm2/s, respectively.
The serum bilirubin isomers, native Z,Z-bilirubin and photoisomers Z,E-bilirubin, E,Z-bilirubin and E,Z-lumirubin (cyclobilirubin), were identified and quantified using isocratic reverse phase high performance liquid chromatography.

Results: The demographic and clinical data for the two groups were comparable. The decrease of Z,Z-bilirubin and increase of each of the photoisomers were as expected highly statistical significant.
The percentage decrease of the combined bilirubin isomers was 55.6 % for the blue-green light versus 44.2 % for the blue light, the ratio between them being 1.43. The corresponding values for Z,Z-bilirubin were 47.8 % versus 33.4 %, the ratio between them being 1.26. The increase in the serum concentrations of the photoisomer Z,E-bilirubin and combined bilirubin photoisomers was greater for the blue light.
After 24 hours of treatment the serum fractions (percentages) of combined photoisomers and Z,E-bilirubin were greater using blue light, while the fraction of E,Z-bilirubin was greater, and E,Z-lumirubin tented to be greater, using blue-green light.

Conclusion(s): Blue-green LED light was essentially more efficient determined by 1) the combined bilirubin isomers, the efficacy being 43 % greater for the blue-green light, and 2) the corresponding efficacy for Z,Z-bilirubin itself was 26 % greater. The serum concentrations of Z,E-bilirubin and combined bilirubin photoisomers increased more using blue light.