From the Research
Phototherapy should typically be initiated for a 3-4 day old infant when their total serum bilirubin level reaches 15-18 mg/dL (257-308 μmol/L), depending on the infant's risk factors. For low-risk infants (term, healthy), start phototherapy at 18 mg/dL. For medium-risk infants (near-term or with minor risk factors), start at 16 mg/dL. For high-risk infants (preterm or with significant risk factors), start at 15 mg/dL. Risk factors to consider include gestational age, presence of hemolytic disease, and other clinical conditions like sepsis or dehydration.
The most recent and highest quality study, 1, provides evidence on the efficacy of hospital phototherapy for neonatal jaundice and the number needed to treat to prevent one infant from reaching the exchange transfusion level. However, the American Academy of Pediatrics guidelines are more relevant to this question, which are reflected in study 1.
Key points to consider:
- Continuous phototherapy should be administered using blue light (wavelength 460-490 nm) for maximum effectiveness.
- Monitor bilirubin levels every 4-6 hours initially, then every 12-24 hours as levels stabilize.
- Phototherapy works by converting bilirubin in the skin to water-soluble isomers that can be excreted without liver conjugation.
- Early treatment prevents the potential neurotoxic effects of high bilirubin levels on the developing brain.
- The number needed to treat with phototherapy varies considerably across different infant subgroups, as shown in study 1.
In terms of specific bilirubin levels for initiating phototherapy, the evidence suggests that:
- For low-risk infants, phototherapy can be started at a bilirubin level of 18 mg/dL.
- For medium-risk infants, phototherapy can be started at a bilirubin level of 16 mg/dL.
- For high-risk infants, phototherapy can be started at a bilirubin level of 15 mg/dL.
It's essential to consider the individual risk factors for each infant when determining the appropriate bilirubin level for initiating phototherapy, as emphasized in study 1.