The pattern of bilirubin response to phototherapy for neonatal hyperbilirubinaemia

Pediatr Res. 1982 Aug;16(8):670-4. doi: 10.1203/00006450-198208000-00018.


The pattern of bilirubin response to phototherapy was studied using lamps with an emission spectrum closely similar to the bilirubin absorption spectrum. A dose-response relationship was demonstrated, with increased intensity of phototherapy resulting in greater response; however, the rate of bilirubin decline progressively decreased with increasing radiance till a 'saturation' point was reached, beyond which no further response occurred with further increase in radiance, suggesting a curvilinear relationship of the nature of an asymptotic regression. At the 'saturation' point, a 24-h decline of about 50% was achieved. With extended periods of phototherapy, a gradually decreasing response to phototherapy with declining bilirubin levels was observed, both with maximal or moderate intensity phototherapy; an exponential regression was suggested. At about 5 mg/dl little further decline was observed with continued phototherapy. The rate of the 24-h decline evaluated at 6-h intervals was observed to be proportional to the bilirubin level at the start of the 24-h period.

MeSH terms

  • Bilirubin / blood*
  • Dose-Response Relationship, Radiation
  • Humans
  • Infant, Newborn
  • Jaundice, Neonatal / blood
  • Jaundice, Neonatal / radiotherapy*
  • Time Factors
  • Ultraviolet Therapy*


  • Bilirubin