The expected effect of phototherapy
Phototherapy uses light to change unconjugated bilirubin in the skin into water-soluble isomers. These isomers can be excreted in bile and urine without needing conjugation by the liver. As more bilirubin reaches the gut, stools become loose and greenish. Frequent loose, green stools are an expected effect of phototherapy, and the nurse can explain this to the parents.
What the nurse monitors at the same time
Although loose stools are expected, they increase fluid loss. Phototherapy also raises insensible water loss through the skin. The nurse therefore watches hydration closely by counting wet diapers, weighing the infant, and checking feeding, and monitors temperature because the infant is exposed and under a light source. The eyes are shielded, the skin is exposed as fully as possible, and the infant's position is changed so the light reaches more of the skin.
Why the other findings are not expected
| Finding | Meaning | Nursing response |
|---|
| Pale, clay-colored stools | Bilirubin is not reaching the gut; suggests conjugated hyperbilirubinemia such as biliary atresia | Report; a direct bilirubin test is needed |
| Bronze-gray skin | Bronze baby syndrome, seen when phototherapy is used in conjugated hyperbilirubinemia | Report; it is not an expected effect |
| Fewer wet diapers | Dehydration from increased water loss | Report and increase fluid intake as ordered |
Watch out! The two stool options look similar but mean opposite things. Green stools show that bilirubin is being cleared through the gut, while pale stools show that it is not getting there at all. Pale stools during treatment should never be passed off as a side effect of phototherapy.
Exam takeaway
Phototherapy makes bilirubin water-soluble, so loose green stools and darker urine are expected, while signs of dehydration, pale stools, or bronze skin are not. When teaching parents, the nurse explains the expected stool changes so they are not alarmed, and asks them to report fewer wet diapers or poor feeding.