Value and limitations of bilirubin binding capacity in predicting the development of kernicterus

An evidence-based review of important issues concerning neonatal hyperbilirubinemia

This article is adapted from a published evidence report concerning neonatal hyperbilirubinemia with an added section on the risk of blood exchange transfusion (BET). Based on a summary of multiple case reports that spanned more than 30 years, we conclude that kernicterus, although infrequent, has at least 10% mortality and at least 70% long-term morbidity. It is evident that the preponderance of kernicterus cases occurred in infants with a bilirubin level higher than 20 mg/dL. Given the diversity of conclusions on the relationship between peak bilirubin levels and behavioral and neurodevelopmental outcomes, it is apparent that the use of a single total serum bilirubin level to predict long-term outcomes is inadequate and will lead to conflicting results. Evidence for efficacy of treatments for neonatal hyperbilirubinemia was limited. Overall, the 4 qualifying studies showed that phototherapy had an absolute risk-reduction rate of 10% to 17% for prevention of serum bilirubin levels higher than 20 mg/dL in healthy infants with jaundice. There is no evidence to suggest that phototherapy for neonatal hyperbilirubinemia has any long-term adverse neurodevelopmental effects. Transcutaneous measurements of bilirubin have a linear correlation to total serum bilirubin and may be useful as screening devices to detect clinically significant jaundice and decrease the need for serum bilirubin determinations. Based on our review of the risks associated with BETs from 15 studies consisting mainly of infants born before 1970, we conclude that the mortality within 6 hours of BET ranged from 3 per 1000 to 4 per 1000 exchanged infants who were term and without serious hemolytic diseases. Regardless of the definitions and rates of BET-associated morbidity and the various pre-exchange clinical states of the exchanged infants, in many cases the morbidity was minor (eg, postexchange anemia). Based on the results from the most recent study to report BET morbidity, the overall risk of permanent sequelae in 25 sick infants who survived BET was from 5% to 10%.

Brain stem electric response audiometry in neonates with hyperbilirubinemia

Auditory evoked responses using BERA were studied in 30 newborn babies with plasma bilirubin > or = 15 mgm/dl and repeated after treatment of neonatal jaundice with bilirubin levels of < or = 10 mgm/dl. A few jaundiced babies (16.5%) showed absent BERA response at the initial/subsequent examination. After treatment, 3/30 babies showed absent wave form responses and 2 of these were clinically kernicteric. Jaundiced babies had prolonged wave peak latencies and inter peak latencies. Treated babies showed a tendency towards recovery in their BERA responses which were however not complete. Total plasma bilirubin value at the time of BERA examination and mean maximal bilirubin values had no correlation with the incidence and degree of BERA abnormalities.