Newborn jaundice happens when bilirubin, a yellow pigment made during normal red blood cell breakdown, builds up faster than a baby's body can remove it. Phototherapy treats jaundice by using carefully chosen blue light that shines on the baby's skin. This medical technology matters because high bilirubin levels can be dangerous if they reach the brain.
With proper monitoring, phototherapy is a safe and common treatment that helps many newborns recover without invasive procedures.
Blue light changes bilirubin molecules in the skin into forms that dissolve more easily in water. These changed forms can leave the body through urine and stool without needing as much processing by the liver. Phototherapy lamps often use LEDs because they can produce a strong blue wavelength range while limiting heat.
Nurses and doctors protect the baby's eyes, expose enough skin, and track bilirubin levels to make sure the treatment is effective.
Key Facts
- Bilirubin is produced when hemoglobin from old red blood cells is broken down.
- Effective phototherapy uses blue light, often near wavelengths of 460 to 490 nm.
- Photon energy is given by E = hf, where h is Planck's constant and f is light frequency.
- Light speed, wavelength, and frequency are related by c = λf.
- Phototherapy converts bilirubin into more water-soluble isomers that can be excreted.
- Treatment effectiveness depends on light wavelength, irradiance, exposed skin area, and distance from the lamp.
Vocabulary
- Jaundice
- Jaundice is yellowing of the skin and eyes caused by a buildup of bilirubin in the body.
- Bilirubin
- Bilirubin is a yellow pigment formed when the body breaks down hemoglobin from old red blood cells.
- Phototherapy
- Phototherapy is a medical treatment that uses light to cause helpful chemical changes in the body.
- Irradiance
- Irradiance is the light power delivered to a surface per unit area, often measured in mW/cm².
- Isomer
- An isomer is a molecule with the same atoms as another molecule but a different arrangement or shape.
Common Mistakes to Avoid
- Thinking any bright light can treat jaundice is wrong because bilirubin responds best to specific blue wavelengths and controlled medical irradiance.
- Placing the lamp too far from the baby is wrong because irradiance decreases with distance, making treatment less effective.
- Covering too much of the baby's skin is wrong because phototherapy works through light reaching the skin where bilirubin is present.
- Assuming phototherapy destroys bilirubin completely is wrong because it mainly changes bilirubin into forms the baby can excrete more easily.
Practice Questions
- 1 A phototherapy LED emits blue light with wavelength 470 nm. Using c = 3.00 x 10^8 m/s, calculate the frequency of the light.
- 2 A lamp delivers an irradiance of 30 mW/cm² over 600 cm² of exposed skin. What total light power reaches the skin in mW?
- 3 Explain why a blue LED phototherapy lamp is more effective for newborn jaundice than a warm white room light, even if the room light looks bright.