Page 133 - 16Neonatal Jaundice_compressed

Neonatal jaundice

For babies of 38 weeks or more gestation, a threshold of 450 micromol/litre from 42 hours of
age onward was agreed by informal consensus. This level was chosen based on the GDG’s
agreement that it was widely accepted that kernicterus would be very unusual in term babies
with serum bilirubin levels lower than this. The GDG noted that this was comparable with the
American Academy of Paediatrics recommendation of 430 micromol/litre and with reported
thresholds currently used in many units in the UK. In the first 42 hours of life, again based on
1
informal consensus, the GDG agreed on a series of bilirubin levels with 6-hourly stepwise
increases at which exchange transfusion is recommended until the 42-hour threshold of
450 micromol/litre is reached. These recommended levels are also presented in table form (see
the threshold table in Section 1.3).
Exchange transfusion thresholds for babies less than 38 weeks of gestation
For preterm babies, the GDG again agreed to use a simple formula (bilirubin in
micromol/litre = gestational age × 10) that has been proposed for use in paediatric textbooks
for many years. Based on informal consensus, the GDG agreed that this formula should also be
used for babies aged 72 hours or older.
For babies less than 72 hours old, based on informal consensus, the GDG agreed that the
threshold should be lower for the reasons outlined above. It was again agreed that for babies
less that 38 weeks of gestation the threshold for phototherapy is best presented using a series of
graphs (see the treatment threshold graphs) of total bilirubin versus age in hours, with a separate
graph for each gestational age (from 23 weeks to 37 weeks of gestation). The graphs were
constructed using the formula for the period from 72 hours of age and older. The threshold
levels during the first 72 hours were determined by drawing a straight line from a level of
80 micromol/litre at birth to the formula-based level at 72 hours.
The GDG considered that these threshold recommendations for phototherapy and exchange
transfusion do not represent a significant departure from mainstream practice in the UK and are
similar to those currently in use in the USA, will discourage extreme practices, and will be of
practical value for clinicians. Furthermore, by standardising national practice, use of the
recommended treatment thresholds will allow meaningful studies of outcome to be performed
nationally in the future.

Finally, the RCTs of phototherapy (reviewed in Section 7.2), which could be considered to be
‘best practice’, predominantly assessed serum bilirubin levels every 6–12 hours to monitor
treatment progress. The GDG decision to use 6-hourly intervals for repeat bilirubin testing was
driven by the need to detect rapidly rising bilirubin (> 8.5 micromol/litre per hour), which may
be an indicator of haemolysis.
The GDG considered 50 micromol/litre below the exchange transfusion threshold to be a
reasonable level at which to step down from multiple phototherapy to single phototherapy. This
would avoid exposing babies to multiple phototherapy, with the restrictions on parental contact
and feeding that this entails, for longer than necessary.
The GDG also agreed that 50 micromol/litre below the phototherapy threshold would be a
resonable level at which to stop conventional phototherapy. This would avoid keeping babies
under phototherapy longer than necessary.
Recommendations
See the end of Section 7.1.

7.1.2 Discharge and monitoring

As there was overlap between these questions, one search was carried out for all questions.
Primary screening of 418 titles and abstracts from the database searches led to the retrieval of
17 full-text papers.

Description of included studies

Two studies, an RCT 125 of different serum bilirubin levels as criteria for stopping phototherapy
and an uncontrolled clinical study 126 of an a priori serum bilirubin level to indicate rebound

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