Shining light on hyperbilirubinemia: optical diagnosis and therapy
Lida Dam-Vervloet is a PhD student in the department of Biomedical Photonic Imaging. (Co)Promotors are prof.dr.ir. N. Bosschaart and prof.dr.ir. W. Steenbergen from the faculty S&T and dr.ir. L. Poot from Isala.
Jaundice in newborn infants is a common condition and it affects up to 60% of term, and 80% of preterm newborn infants. Timely treatment of jaundiced newborn infants with phototherapy can prevent severe hyperbilirubinemia. Hyperbilirubinemia may result in kernicterus spectrum disorders, potentially causing irreversible brain damage. Transcutaneous bilirubinometry (TcB) is a non-invasive screening method for hyperbilirubinemia, which can reduce the number of invasive and painful total serum bilirubin (TSB) determinations. In this thesis, we evaluate how TcB measurements are affected by biological variations in the optical properties of neonatal skin. The optical properties of neonatal skin can vary significantly, due to differences in skin composition. A better understanding of the influence of these differences in skin composition is important for the interpretation of TcB measurements on newborn infants.
Based on the in vitro and in vivo TcB measurements in this thesis, it can be concluded that biological variations in the optical properties of neonatal skin and the inter-device reproducibility of the TcB meter itself have a significant effect on TcB measurements. Some of the underestimations and overestimations exceeded the TcB meter's specified accuracy, as well as the clinical safety margin.
Treatment of hyperbilirubinemia
Phototherapy (PT) is the standard treatment of neonatal hyperbilirubinemia. The American Academy of Pediatrics recommends a spectral irradiance output of at least 30 μWcm−2nm−1 blue light for intensive PT, that covers as much of the body surface area of a newborn infant as possible.
Measurements of the spectral irradiance and spectral irradiance footprint, i.e. the illuminated area by the PT device with sufficient spectral irradiance, are essential for PT to be effective, but guidelines on how to measure these two parameters are not included in hyperbilirubinemia guidelines. As a consequence, these measurements are not performed in current clinical practice.
Based on the measurements in this thesis, it can be concluded that the spectral irradiance and the HSI footprint is dependent on the brand and type of PT devices, which causes the effectiveness of the PT therapy to vary.
