In vivo spectroscopy of jaundiced newborn skin reveals more than a bilirubin index.
OBJECTIVE
The aims of this study were to improve the algorithms for calculating a transcutaneous bilirubin index (TcB), to follow the bilirubin concentrations during phototherapy and to evaluate possible changes in skin optical parameters such as pigmentation and erythema during phototherapy.


METHODS
Reflectance measurements were performed on 51 jaundiced newborns, of which 10 were subjected to phototherapy. The measurements were collected with a diode array spectrophotometer with an integrating sphere accessory, and a TcB was calculated from the measured spectra using algorithms based on diffusion theory. The newborns' birthweights were > or = 2000 g and their gestational age was > or = 35.5 wk. They had no substantial illnesses, and no newborns were submitted to the study until their second day. Heel prick blood samples were analysed for total serum bilirubin (Sbr) by the diazo reaction method. Phototherapy equipment was either an overhead lamp or lightbed.


RESULTS
Measurements from the forehead gave the best correlation between TcB and Sbr (r = 0.81, p < 0.05). However, during phototherapy no significant correlation between TcB and Sbr was observed. A correlation (r = 0.45, p < 0.05) was found between phototherapy and melanin index obtained from the patients' back.


CONCLUSIONS
Reflectance spectroscopy is useful in assessing bilirubin concentrations before phototherapy, and can also reveal changes in skin parameters such as pigmentation occurring as a result of phototherapy.
Randeberg
L Lyngsnes
LL
Department of Electronics and Telecommunications, Norwegian University of Science and Technology, Trondheim, Norway. lise.randeberg@iet.ntnu.no
Roll
E Bruzell
EB
Nilsen
L T Norvang
LT
Christensen
T
T
Svaasand
L O
LO
D000465:Algorithms; D001663:Bilirubin / Q000032:analysis* / Q000097:blood; D004890:Erythema / Q000209:etiology / Q000378:metabolism; D006801:Humans; D007231:Infant, Newborn; D007567:Jaundice, Neonatal / Q000378:metabolism* / Q000628:therapy; D008543:Melanins / Q000378:metabolism; D015997:Neonatal Screening / Q000379:methods; D010789:Phototherapy / Q000009:adverse effects; D012867:Skin / Q000378:metabolism*; D013053:Spectrophotometry / Q000379:methods*
D008543:Melanins; D001663:Bilirubin