From the Guidelines
Phototherapy is recommended for your baby's bilirubin level of 185 micromoles per liter, as it is a safe and effective treatment for newborn jaundice, and staying another night for treatment is appropriate. Phototherapy uses special blue lights to break down bilirubin in the skin, allowing it to be excreted more easily, by exposing newborn infants to light in the blue-green wavelength range (460–490 nm), preferably at an optimal peak of 478 nm and at an irradiance of 25 to 35 mW/cm2/nm to at least 1 surface of the body (ventral or dorsal) 1. The photoconversion of the unconjugated bilirubin molecule mostly occurs in the microcirculation of the skin with almost immediate photo-isomerization to the excretable water soluble 4E,15Z photoisomer, peaking within 120 minutes, resulting in a presumably rapid decrease of excessive unconjugated bilirubin concentrations and the subsequent reduction of potential exposure to neurotoxicity 1. Your baby's bilirubin level is mildly elevated but not severely concerning for a 48-hour-old infant, however, it does warrant treatment to prevent further increase, as the acceptable bilirubin range at 48 hours is <200 μmol/L (11.7 mg/dL) in the USA. During phototherapy:
- Ensure maximum skin exposure to the lights
- Continue frequent feedings (every 2-3 hours) to promote bilirubin excretion
- Monitor for signs of dehydration The doctor will likely recheck bilirubin levels after 12-24 hours of treatment, and the decision to discontinue phototherapy should be individualized to consider the TSB level at which phototherapy was initiated, the cause of the hyperbilirubinemia, the difference between the TSB level and the phototherapy threshold, and the risk of rebound hyperbilirubinemia 1. Most babies respond well to phototherapy within 1-2 days, and once levels decrease sufficiently, you'll be able to go home, but follow-up testing may be needed to ensure levels don't rise again. It is essential to follow the guidelines for phototherapy, including the measurement of total serum/plasma bilirubin (TSB) concentrations, screening for intrinsic risk factors for bilirubin neurotoxicity, and evaluating the underlying cause of hyperbilirubinemia 1.
From the Research
Mechanism of Phototherapy
- Phototherapy is a treatment used to reduce bilirubin levels in newborns with hyperbilirubinemia 2, 3, 4.
- The mechanism of phototherapy involves the use of light to convert bilirubin into a water-soluble form that can be easily excreted by the body 4.
Recommendation for Phototherapy
- The American Academy of Pediatrics (AAP) recommends phototherapy for newborns with bilirubin levels above certain thresholds, which vary based on gestational age and the presence of neurotoxicity risk factors 2, 3.
- For a 48-hour-old neonate, phototherapy is recommended if the bilirubin level is at or above 15 mg/dL (257 micromol/L) 3.
- In this case, the neonate's bilirubin level is 185 micromoles per liter, which is approximately 10.8 mg/dL, below the recommended threshold for phototherapy 3.
Acceptable Ranges in the USA
- The acceptable ranges for bilirubin levels in newborns vary based on gestational age, age in hours, and the presence of neurotoxicity risk factors 2, 3.
- The AAP provides hour-specific phototherapy nomograms to guide the initiation of phototherapy based on these factors 2.
- For a term newborn, the AAP recommends phototherapy if the bilirubin level is above the 95th percentile for age in hours, which is approximately 15 mg/dL (257 micromol/L) at 25-48 hours of age 3.
Risks and Benefits of Phototherapy
- Phototherapy has the potential for short- and long-term adverse effects, including diarrhea and increased risk of seizures 2.
- However, phototherapy can also decrease the need for exchange transfusion and reduce the risk of kernicterus 2, 4.
- The decision to initiate phototherapy should be based on a careful evaluation of the benefits and risks, taking into account the individual newborn's gestational age, age in hours, and presence of neurotoxicity risk factors 2, 3.