From the Guidelines
Phototherapy is recommended for a 48-hour-old neonate with a bilirubin level of 185 micromoles per liter, as it is an effective treatment for hyperbilirubinemia and helps prevent potential complications such as kernicterus. The mechanism of phototherapy involves exposing the newborn to light in the blue-green wavelength range, which converts unconjugated bilirubin into a water-soluble form that can be easily excreted 1. This process occurs in the microcirculation of the skin and results in a rapid decrease in excessive unconjugated bilirubin concentrations, reducing the risk of neurotoxicity.
The American Academy of Pediatrics recommends phototherapy for newborns with bilirubin levels above certain thresholds, which vary based on the baby's age in hours 1. For a 48-hour-old infant, the acceptable bilirubin range is less than 200 μmol/L (11.7 mg/dL). Since the baby's bilirubin level is 185 μmol/L, which is close to the threshold, phototherapy is warranted to prevent further increase.
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 Phototherapy is typically continued until bilirubin levels drop below treatment thresholds, usually within 24-48 hours 1. Follow-up testing after discharge is often recommended to ensure levels don't rise again.
It is essential to note that the decision to discontinue phototherapy should be individualized, considering the TSB level at which phototherapy was initiated, the cause of the hyperbilirubinemia, and the risk of rebound hyperbilirubinemia 1. Additionally, infants who received phototherapy should have a follow-up TSB measure within 1 to 2 days after phototherapy discontinuation to ensure that bilirubin levels do not rise again.
From the Research
Mechanism of Phototherapy
- Phototherapy is a treatment used to reduce bilirubin levels in neonates with hyperbilirubinemia 2.
- The mechanism of phototherapy involves the conversion of bilirubin into a water-soluble form that can be easily excreted by the body 3.
- Phototherapy uses light to break down bilirubin into smaller molecules that can be removed from the body, thereby reducing the risk of bilirubin-induced neurological dysfunction (BIND) 2.
Recommendation for Bilirubin Level of 185 micromoles per liter
- The provided studies do not specifically address the recommendation for phototherapy for a bilirubin level of 185 micromoles per liter in a 48-hour-old neonate 2, 3, 4, 5.
- However, one study mentions a bilirubin concentration of 185-550 micromol/l in patients with benign recurrent intrahepatic cholestasis, but this is not directly relevant to neonatal hyperbilirubinemia 6.
- Another study discusses the classification of extreme hyperbilirubinemia into four grades, with grade 1 being 12-14.9 mg/dL, but does not provide a specific recommendation for a bilirubin level of 185 micromoles per liter 4.
Acceptable Ranges in the USA
- The studies do not provide information on acceptable ranges for bilirubin levels in neonates in the USA 2, 3, 4, 5.
- One study mentions that total serum bilirubin test results should be accurate within permissible limits of measurement uncertainty to be fit for clinical purposes, but does not specify the acceptable ranges 3.