Premature infants, especially those born at 27 weeks of gestation, face numerous physiological challenges, one of which is hyperbilirubinemia. Phototherapy is a cornerstone treatment for neonatal jaundice, helping reduce bilirubin levels and prevent complications such as kernicterus. At 27 weeks, the infant’s liver, gastrointestinal system, and neurological regulation are immature, making bilirubin metabolism inefficient. In addition, preterm infants are more susceptible to the side effects of hyperbilirubinemia, and phototherapy requires careful monitoring of hydration, temperature, and overall health. Understanding the rationale, indications, mechanisms, and management strategies for phototherapy in extremely preterm infants is critical for neonatal clinicians and caregivers.
Physiological Basis of Hyperbilirubinemia in Preterm Infants
Bilirubin is produced from the breakdown of red blood cells. In preterm newborns:
- The liver’s conjugating enzyme UDP-glucuronyl transferase is immature.
- Increased red blood cell turnover results in elevated bilirubin production.
- Delayed feeding can reduce bilirubin excretion.
Consequently, 27-week preterm infants often develop unconjugated hyperbilirubinemia, which can accumulate to toxic levels and deposit in the basal ganglia, causing kernicterus if untreated.
Indications for Phototherapy
Phototherapy is indicated based on gestational age, bilirubin levels, and risk factors:
- Bilirubin thresholds are lower in extremely preterm infants; guidelines suggest initiating phototherapy at lower levels than term infants.
- Risk factors include hemolysis, sepsis, hypoxia, acidosis, and low albumin levels.
- Continuous or intensive phototherapy may be required for rapidly rising bilirubin or very low birth weight infants.
Mechanism of Phototherapy
Phototherapy uses blue-green light (wavelength 460–490 nm) to convert unconjugated bilirubin in the skin into water-soluble photoisomers, which can be excreted without conjugation in the liver. Key mechanisms include:
- Photo-oxidation: Converts bilirubin into non-toxic compounds.
- Structural isomerization: Forms lumirubin, easily excreted via bile and urine.
Clinical Monitoring During Phototherapy
Extremely preterm infants require meticulous monitoring:
- Temperature: Preterm infants are prone to hypothermia or hyperthermia under phototherapy lights.
- Hydration and fluid balance: Phototherapy increases insensible water loss; careful monitoring of intake, urine output, and electrolytes is essential.
- Skin integrity: Fragile preterm skin may develop erythema or burns if phototherapy is excessive.
- Eye protection: The eyelids must be shielded to prevent retinal damage.
Table 1. Phototherapy Monitoring Parameters in 27-Week Preterm Infants
| Parameter | Target/Observation | Frequency |
|---|---|---|
| Serum bilirubin | Monitor levels according to gestational age thresholds | Every 6–12 hours |
| Temperature | Maintain 36.5–37.5°C | Continuous |
| Urine output | 1–2 mL/kg/hr minimum | Every shift |
| Electrolytes | Sodium, potassium | Daily or as needed |
| Eye protection | Proper eye shields in place | Continuous |
Risks and Complications of Phototherapy
While generally safe, phototherapy in preterm infants carries risks:
- Dehydration due to increased water loss.
- Hyperthermia or hypothermia because of immature thermoregulation.
- Bronze baby syndrome: Rare, mild skin discoloration.
- Retinal injury: Preventable with eye shields.
- Interference with bonding: Prolonged phototherapy limits skin-to-skin contact.
- Potential oxidative stress: Extremely preterm infants are more vulnerable to free radical damage.
Feeding and Nutrition Considerations
Adequate nutrition is critical for bilirubin excretion. For a 27-week preterm infant:
- Parenteral nutrition may be required initially.
- Minimal enteral feeding (trophic feeds) supports gut maturation and bilirubin elimination.
- Breast milk provides immunological benefits and helps reduce bilirubin levels.
- Fluid intake must be carefully balanced to prevent dehydration or overload during phototherapy.
Integration with Other NICU Care
Phototherapy is part of a multifaceted care plan in the NICU:
- Ventilatory support if the infant is respiratory-compromised.
- Temperature regulation in an incubator.
- Infection prevention through strict hand hygiene and monitoring.
- Developmental care, including minimizing noise and light exposure outside phototherapy periods.
Socioeconomic and Healthcare Considerations
In the U.S., extremely preterm infants receiving phototherapy require advanced NICU care, which may involve prolonged hospitalization. Insurance coverage and access to specialized neonatal units can influence outcomes. Families may experience stress and require education on phototherapy purpose, expected duration, and signs of complications. Telehealth follow-up and home phototherapy are sometimes considered for stable infants after discharge, depending on resources and parental support.
Long-Term Outcomes
With timely and appropriate phototherapy, most preterm infants experience normalization of bilirubin without neurological sequelae. Continuous monitoring and follow-up are critical to ensure:
- Normal neurodevelopment.
- Growth progression according to gestational age charts.
- Early detection of complications like chronic lung disease or retinopathy of prematurity, which may co-exist in extremely preterm infants.
Conclusion
A 27-week preterm newborn receiving phototherapy represents a complex clinical scenario requiring precise monitoring and comprehensive care. Hyperbilirubinemia in extremely preterm infants can lead to severe neurological damage if untreated, but phototherapy remains a highly effective intervention. Coordinated NICU care, including temperature regulation, hydration management, nutritional support, and eye protection, ensures safe and successful treatment. With modern neonatal care, even extremely preterm infants can achieve favorable outcomes, emphasizing the importance of timely intervention and family-centered education.