North American Indians were appar¬ ently aware that exposure to sunlight reduced the yellow colour of babies. Bright indirect daylight is also effect¬ ive in bringing about this reduction and may account for the alleged lower incidence of hyperbilirubinemia in sunny regions.1 For some time labo¬ ratory technicians have known that bilirubin levels are lower in samples of plasma exposed to light than in samples stored in thedark. Biochemically the change that occurs is a par¬ tial breakdown of bilirubin with a resulting shift in the absorption spec¬ trum ofthe serum.2

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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%.

Discharge at any time < 72 hours significantly increases the risk for readmission to hospital and the risk for readmission with hyperbilirubinemia when compared with discharge after 72 hours. The American Academy of Pediatrics recommends that infants discharged < 48 hours should be seen by a health care professional within 2 to 3 days of discharge. Our observations, as well as those of others, suggest that this recommendation should also be extended to those discharged at < 72 hours after birth. One approach to decreasing the risk of morbidity and readmission, particularly from hyperbilirubinemia, would be to help mothers to nurse their infants more effectively from the moment of birth.

We conclude that TcB measurements using the JM-103 jaundice meter correlate very closely with TSB levels over the range of TSB encountered in this study. Because only 3.3% of our infants had TSB values >15 mg/dL (257 micro mol/L), more data are needed in this range of TSB concentration. The correlation in black infants is not as close as in other groups, but because the tendency in blacks is for the JM-103 to overestimate serum bilirubin levels, dangerous clinical errors are unlikely to occur. The measurement technique is rapid and simple, and it is easy to perform repeated measurements over time, thus reducing the likelihood of error. TcB measurements with the JM-103 jaundice meter should obviate the need for most serum bilirubin levels in newborn infants > or =35 weeks of gestation, although serum bilirubin measurements are still required when treatment with phototherapy or exchange transfusion is being considered.

Kernicterus, thought to be due to severe hyperbilirubinemia, is an uncommon disorder with tragic consequences, especially when it affects healthy term and near-term infants. Early identification, prevention and treatment of severe hyperbilirubinemia should make kernicterus a preventable disease. However, national epidemiologic data are needed to monitor any preventive strategies. Recommendations are provided to obtain prospective data on the prevalence and incidence of severe hyperbilirubinemia and associate mortality and neurologic injury using standardized definitions, explore the clinical characteristics and root causes of kernicterus in children identified in the Kernicterus Pilot Registry, identify and test an indicator for population surveillance, validating systems-based approaches to the management of newborn jaundice, and explore the feasibility of using biologic or genetic markers to identify infants at risk for hyperbilirubinemia. Increased knowledge about the incidence and consequences of severe hyperbilirubinemia is essential to the planning, implementation and assessment of interventions to ensure that infants discharged as healthy from their birth hospitals have a safer transition to home, avoiding morbidity due to hyperbilirubinemia and other disorders. At a recent NIHCD-sponsored conference, key questions were raised about kernicterus and the need for additional strategies for its prevention. These questions and an approach to their answers form the basis of this report.

We provide an approach to the use of phototherapy and exchange transfusion in the management of hyperbilirubinemia in preterm infants of <35 weeks of gestation. Because there are limited data for evidence-based recommendations, these recommendations are, of necessity, consensusbased. The recommended treatment levels are based on operational thresholds for bilirubin levels and represent those levels beyond which it is assumed that treatment will likely do more good than harm. Long-term follow-up of a large population will be needed to evaluate whether or not these recommendations should be modified.

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