Phototherapy for Neonatal Jaundice – Effective Treatment & Benefits Explain

Phototherapy for Neonatal Jaundice – Effective Treatment & Benefits Explained 

Phototherapy remains the major cornerstone in the management of neonatal hyperbilirubinemia. It is highly effective and has demonstrated a strong safety profile for over five decades. The primary mechanism involves the conversion of insoluble unconjugated bilirubin into water-soluble isomers that can be excreted through urine and faeces. Several review articles have extensively discussed phototherapy-related aspects. Under exposure to blue-green light (460–490 nm), bilirubin undergoes isomerization into non-toxic forms. Light sources emitting high irradiance within this wavelength range are more efficacious compared to others1

For phototherapy to be effective, bilirubin must be present in the skin, which is why prophylactic phototherapy has no role. 

The mechanisms by which phototherapy reduces bilirubin levels include:

1. Configurational isomerization: This process converts Z-isomers of bilirubin into E-isomers. Although this reaction is instantaneous upon light exposure, it is reversible as bilirubin enters the bile duct. After 8–12 hours of phototherapy, approximately 25% of total serum bilirubin (TSB) exists in this non-toxic form. However, as this isomer is excreted slowly, it does not significantly contribute to TSB reduction2.

2. Structural isomerization: An irreversible reaction converting bilirubin into lumirubin, a water-soluble product that is rapidly excreted. The extent of this reaction is directly proportional to the dose of phototherapy, forming 2–6% of TSB, making it the primary mechanism responsible for bilirubin reduction3.

3. Photo-oxidation: A minor pathway in which bilirubin photoproducts are excreted in urine4.

Types of Phototherapy Lights:

Various phototherapy units are available, utilizing different light sources such as fluorescent lamps (cool white, blue, green, blue-green, or turquoise), compact fluorescent lamps (CFL), halogen bulbs, high-intensity light-emitting diodes (LEDs), and fiber-optic devices5.

CFL-based phototherapy remains the most commonly used in India due to its affordability and accessibility. Standard CFL units typically contain four blue and two white tubes (for examination purposes), though replacing the white lamps with additional blue CFLs enhances irradiance output6.

Recently, blue LED-based phototherapy has gained traction in neonatal care. LEDs offer advantages such as an extended lifespan (up to 50,000 hours) and the capability to provide higher irradiance than CFL lamps7.

Optimizing Phototherapy Efficacy

The irradiance of phototherapy lights should be periodically assessed, ensuring a minimum level of 30 µW/cm²/nm within the 460–490 nm wavelength range. Lamps should be replaced if flickering occurs, ends are blackened, irradiance drops below recommended levels, or as per manufacturer guidelines8.

Additional measures to enhance efficacy include:

• Maximizing the exposed surface area of the infant.

• Preventing light obstruction by equipment, large diapers, eye patches, caps, dressings, or electrodes.

• Ensuring adequate hydration and nutrition.

• Positioning lights perpendicular to the baby, especially in an incubator.

• Minimizing interruptions for feeding or procedures9.

Administering Phototherapy

• Maintain an ambient room temperature between 25–28°C to prevent hypothermia or hyperthermia.

• Undress the baby except for a diaper.

• Protect the baby’s eyes with an eye patch, ensuring it does not obstruct the nostrils.

• Position the infant under phototherapy lights in a cot or bassinet (if birth weight >2 kg) or in an incubator/radiant warmer (if birth weight <2 kg).

• Maintain a 30–45 cm distance between the baby and the light source, per manufacturer recommendations10.

Breastfeeding and Phototherapy:

Breastfeeding should be continued during phototherapy. The baby can be taken out for feeding, and the eye patch can be removed to facilitate mother-infant interaction. However, interruptions should be minimized to optimize treatment effectiveness. There is no need to supplement or replace breast milk with alternative feeds, including formula, water, or glucose water11.

Monitoring and Discontinuation

• Monitor the baby's temperature every 2–4 hours.

• Measure TSB levels every 12–24 hours.

• Discontinue phototherapy when two consecutive TSB readings, taken 12 hours apart, fall below the age-specific threshold.

• Clinically monitor for rebound hyperbilirubinemia within 24 hours after discontinuation, especially in infants with hemolytic conditions12.

References

1. Wang J, Guo G, Li A, Cai WQ, Wang X. Challenges of phototherapy for neonatal hyperbilirubinemia (Review). Exp Ther Med. 2021;21(3):231. doi: 10.3892/etm.2021.9662. PMID: 33613704; PMCID: PMC7859475.

2. Ghai OP. Essential Paediatrics. 10th ed. New Delhi: CBS Publishers; 2022.

3. Hockenberry MJ, Wilson D. Wong’s Essentials of Paediatric Nursing. 11th ed. St. Louis: Elsevier; 2021.

4. Maisels MJ, McDonagh AF. Phototherapy for neonatal jaundice. N Engl J Med. 2008;358(9):920-8.

5. American Academy of Pediatrics Subcommittee on Hyperbilirubinemia. Management of hyperbilirubinemia in the newborn infant 35 or more weeks of gestation. Pediatrics. 2004;114(1):297-316.

6. Bhutani VK. Phototherapy and other treatment modalities for neonatal jaundice. In: Stevenson DK, Maisels MJ, Watchko JF, editors. Care of the Jaundiced Neonate. McGraw-Hill; 2012. p. 259-74.

7. Vreman HJ, Wong RJ, Stevenson DK. Phototherapy: current methods and future directions. Semin Perinatol. 2004;28(5):326-33.

8. Tan KL. Phototherapy for neonatal jaundice. Clin Perinatol. 1991;18(3):423-39.

9. Hansen TW. Twists and turns in phototherapy for neonatal jaundice. Acta Paediatr. 2010;99(8):1117-8.

10. Seidman DS, Stevenson DK, Ergaz Z, et al. Clinical applications of neonatal phototherapy. Pediatr Clin North Am. 2004;51(3):819-42.

11. Gartner LM, Herschel M. Jaundice and breast-feeding. Pediatr Clin North Am. 2001;48(2):389-99.

12. Maisels MJ. Neonatal jaundice. Pediatr Rev. 2006;27(12):443-54.

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