Phototherapy
Phototherapy is a core treatment for neonatal jaundice. It works by converting unconjugated bilirubin into water-soluble isomers that can be excreted without conjugation by the liver. A wavelength of 460-490 nm (blue light) is the most effective. A higher irradiance (> 30 uw/nm/cm2) increases bilirubin breakdown. Maximum skin exposure enhances treatment – only a diaper should be worn.
Standard vs intensive phototherapy
| Standard phototherapy | Intensive phototherapy | |
|---|---|---|
| Irradiance | 25 – 30 uW/cm2/nm | 30 – 35 uW/cm2/nm |
| Light source | Single overhead unit | Multiple sources (overhead + biliblanket/sidelights) |
| Indications | Mild-moderate jaundice (serum bilirubin below the level of exchange transfusion by > 50 umol/L) | Severe jaundice (serum bilirubin below the level of exchange transfusion by less than 50 umol/L) |
| Effectiveness | Gradual bilirubin reduction | Rapid bilirubin reduction |
- Indications for starting phototherapy, even when bilirubin measures are unavailable
- Jaundice is easily visible on the sole of a well baby
- Preterm baby with ANY visible jaundice
- Baby with easily visible jaundice + inability to feed or other symptoms of neurological impairment
- Also consider immediate exchange transfusion
- Complications of phototherapy
- Dehydration and fluid loss: increased insensible water loss due to skin exposure and vasodilatation
- Diarrhea: Increased bilirubin breakdown products in bile may irritate the intestines
- Bronze baby syndrome: occurs in cholestatic jaundice (conjugated hyperbilirubinemia). Bilirubin oxidation leads to a gray-brown skin discolouration.
- Hypothermia or hyperthermia: excessive exposure may cause temperature instability, especially in preterm infants
- Retinal damage: prolonged light exposure may cause retinal damage if eye protection is not used
- Rash or burns: possible due to heat from some light sources
- Disrupted mother-infant bonding: separation for long durations may affect breastfeeding and bonding
- Oxidative stress and DNA damage: potential risk in extremely preterm infants due to increased free radical production
Exchange Transfusion
Exchange transfusion is the second-line treatment for severe hyperbilirubinemia, especially when bilirubin levels approach neurotoxic levels (> 513 umol/L). It works by removing the infant’s blood and replacing it with donor blood to rapidly reduce bilirubin levels.
Single vs Double Volume Exchange Transfusion
| Single volume exchange | Double volume exchange | |
|---|---|---|
| Definition | Replacement of one blood volume (80 – 90 ml/kg) | Replacement of two blood volumes (160 – 180 mL/kg) |
| Effectiveness | Removes 30 – 40% of bilirubin | Removes 85% of bilirubin |
| Indications | Moderate-severe hyperbilirubinaemia | Severe hyperbilirubinaemia or hemolysis |
| Procedure time | Shorter | Longer |
| Risk of complications | Lower | Higher risk of hypovolemia, thrombocytopaenia and electrolyte imbalance |
- Indications for exchange transfusion
- Severe hyperbilirubinemia (above exchange transfusion threshold based on gestational age and risk factors)
- Poor or failed response to phototherapy
- Signs of acute bilirubin encephalopathy
- Complications of exchange transfusion
- Infection: due to central venous catheter insertion and blood product exposure
- Electrolyte imbalance: hypocalcemia (due to citrate), hyperkalemia, hypoglycemia
- Thrombocytopaenia and coagulation: due to the removal of platelets and clotting factors during transfusion
- Volume overload or hypovolemia: Rapid blood shifts can cause circulatory instability
- Cardiac arrhythmia: due to electrolyte disturbances, especially hypocalcemia
- Air embolism: improper technique during transfusion can introduce air into circulation
- Graft-versus-host disease: rare but possible if blood is not properly irradiated in immunocompromised infants
- Necrotizing enterocolitis: potential gut ischemia due to rapid blood volume changes in preterm infants
Appendix: Conversion Factors
1 mg/dL = 17.1 umol/L
1 umol/L = 0.0585 mg/dL
1 mmol/L = 1000 umol/L