Bili lights refer to a type of phototherapy that is used to treat newborn jaundice, a yellow coloring of the skin and eyes related to immature liver function.

Phototherapy is performed on infants who have increased levels of bilirubin in the blood. Bilirubin is a yellow pigment that's created in the body during the normal recycling of old red blood cells.

Phototherapy involves the exposure of bare skin to fluorescent light. The newborn (without clothes or in a small diaper) is placed under the fluorescent lights. The eyes are covered to protect them from the bright light. The blue fluorescent "Bili" lamps give off specific wavelengths of light that help break down bilirubin into nontoxic substances that can leave the body through the urine and stools.

The health care team carefully notes the infant's body temperature, vital signs, length of treatment, positioning of the bulbs, and the newborn's responses. The infant is turned frequently so that the therapy is most effective.

Because dehydration may result from being under the lights, fluids may need to be given through a vein. Blood tests are done to regularly check the bilirubin level. When the levels have dropped enough, phototherapy is complete.

Some infants receive phototherapy at home. In this case, a nurse visits daily and draws a sample of blood for testing.

Treatment depends on three factors:

• Birth weight
• Concentration of bilirubin in the blood
• Newborn's age (in hours)

In severe cases of incrased bilirubin in a low birthweight newborn that is less than 24 hours old, an exchange transfusion may be preferred over phototherapy. With very high bilirubin concentrations, regardless of age and weight, an exchange transfusion may be the best option.