Moderate unconjugated hyperbilirubinemia causes a transient but delayed suppression of amplitude-integrated electroencephalographic activity in preterm infants.
BACKGROUND
Unconjugated hyperbilirubinemia occurs frequently in preterm infants and may result in bilirubin encephalopathy. Amplitude-integrated electroencephalography (aEEG) is used to evaluate brain function in newborns.


OBJECTIVE
To investigate the influence of total serum bilirubin (TSB) on the aEEG amplitude of preterm infants and to evaluate aEEG as a noninvasive method to identify acute bilirubin encephalopathy.


METHODS
We performed a prospective observational study of 34 infants with a gestational age (GA) of 26-31 6/7 weeks. Infants had aEEG recordings on the 1st-5th, 8th and 15th day after birth. Infants with asphyxia, intraventricular hemorrhage >grade I or circulatory insufficiency were excluded. aEEG was evaluated by calculating the mean 5th, 50th and 95th centiles of the aEEG amplitudes.


RESULTS
TSB peaked on the 4th day after birth. There was no synchronous relationship between TSB and aEEG amplitudes. The 5th, 50th, and 95th aEEG amplitude centiles on the 8th day correlated negatively with the TSB peak value (r = -0.37, p = 0.048; r = -0.60, p = 0.001; r = -0.44, p = 0.017, respectively), irrespective of GA. The 5th and 50th aEEG amplitude centiles increased with increasing GA (r = 0.45, p < 0.001, and r = 0.26, p < 0.001, respectively) and postnatal age (r = 0.25, p < 0.001, and r = 0.16, p = 0.023, respectively).


CONCLUSIONS
TSB had no direct effect on aEEG amplitudes in preterm infants. There is, however, a delayed effect on electrocerebral activity in the 2nd week after birth.
Division of Neonatology, Department of Pediatrics, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands. h.j.ter.horst @ bkk.umcg.nl
Hendrik J
HJ
Ter Horst
Arend F
AF
Bos
Jildou
J
Duijvendijk
Christian V
CV
Hulzebos
D000701:Analgesics, Opioid / Q000008:administration & dosage; D001663:Bilirubin / Q000097:blood; D015415:Biomarkers / Q000097:blood; D001921:Brain / Q000187:drug effects / Q000503:physiopathology*; D058256:Brain Waves / Q000187:drug effects; D004569:Electroencephalography; D005865:Gestational Age; D006801:Humans; D051556:Hyperbilirubinemia, Neonatal / Q000097:blood / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy; D007231:Infant, Newborn; D007234:Infant, Premature; D007647:Kernicterus / Q000097:blood / Q000175:diagnosis* / Q000209:etiology / Q000503:physiopathology; D016014:Linear Models; D009020:Morphine / Q000008:administration & dosage; D015999:Multivariate Analysis; D009426:Netherlands; D010789:Phototherapy; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012890:Sleep; D014851:Wakefulness
D000701:Analgesics, Opioid; D015415:Biomarkers; D009020:Morphine; D001663:Bilirubin