Neonatal Nurse Practitioner Practice Exam

The efficacy of phototherapy for jaundice depends primarily on what?

1. Hydration of the infant

2. Duration of exposure

3. Irradiance of the lights

4. Type of phototherapy used

The correct answer is: Irradiance of the lights

The efficacy of phototherapy for jaundice primarily hinges on the irradiance of the lights used during the treatment. Irradiance refers to the amount of light energy that strikes the skin per unit area and is crucial because higher irradiance levels enhance the breakdown of bilirubin in the skin, allowing for more effective treatment. Phototherapy works by converting indirect bilirubin into a more water-soluble form that can be excreted, and sufficient light intensity is essential for this process to occur efficiently. While factors like hydration and duration of exposure can play roles in the overall management of jaundice, they do not have as direct an impact on the fundamental mechanism of how phototherapy works as the irradiance level does. The type of phototherapy used, whether it involves fluorescent lamps, fiberoptic blankets, or newer LED devices, also influences treatment efficacy but is secondary to the importance of adequate irradiance. Thus, ensuring that the light used in phototherapy has optimal irradiance is vital for maximizing the effectiveness of the treatment.