Transcutaneous bilirubinometry during and after phototherapy.
OBJECTIVE
To evaluate the reliability of transcutaneous bilirubinometry (TcB) during and after phototherapy.


METHODS
TcB was performed on the forehead and chest of infants with neonatal jaundice when capillary blood was sampled for bilirubin determination in a control group of 240 neonates. In a second group of 70 neonates exposed to phototherapy the same procedure was performed after at least 24 h of exposure: on the forehead, TcB was done in the centre of the unexposed area and also on the adjacent exposed area, and the exposed chest. During the post-phototherapy period, TcB was again done during the first and second days, at least 18-24 h after cessation of phototherapy. The results were then statistically evaluated and regression curves were plotted.


RESULTS
A close correlation between TcB values and bilirubin levels was observed in the control group. In the phototherapy group, a correlation was also found between the TcB and the bilirubin values, but this correlation was significantly poorer than that of the controls; the correlation for the covered part of the forehead was significantly better than that of the exposed part but still poorer than that of the controls, though the difference was no longer significant. Skin colour recovered during the post-phototherapy period and correlation was better than that during exposure and no longer significantly different from that of the controls.


CONCLUSIONS
Through its bleaching effect on the skin, phototherapy affects the correlation between TcB and the bilirubin values, but does not totally eliminate it. The unexposed parts show a better correlation, though this was still poorer than that of the controls. Recovery of skin colour occurred within 18-24 h after cessation of exposure.
Specialist Infant-Child Centre, Mt. Elizabeth Medical Centre, Singapore. ylkltan@singnet.com.sg
K L
KL
Tan
F
F
Dong
D000279:Administration, Cutaneous; D001663:Bilirubin / Q000032:analysis* / Q000097:blood / Q000528:radiation effects*; D001724:Birth Weight; D005260:Female; D005865:Gestational Age; D006801:Humans; D007231:Infant, Newborn; D007567:Jaundice, Neonatal / Q000097:blood / Q000175:diagnosis* / Q000628:therapy*; D008297:Male; D010789:Phototherapy; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012867:Skin / Q000737:chemistry* / Q000528:radiation effects*; D013997:Time Factors
D001663:Bilirubin