Amplitude-integrated electroencephalographic activity is suppressed in preterm infants with high scores on illness severity

BackgroundThe neonatal acute physiology score, SNAP-II, reflects the severity of illness in newborns. In term newborns, amplitude integrated EEG (aEEG), is depressed following asphyxia. In preterm infants aEEG is discontinuous, and therefore more difficult to assess compared to term infants.AimsOur first aim was to investigate whether assessing aEEG amplitudes by calculating amplitude centiles was consistent with assessment by pattern recognition. Our second aim was to investigate whether the aEEGs of preterm infants were influenced by SNAP-II.Study Design and SubjectsWe recorded aEEGs in 38 infants with a mean gestational age of 29.7 weeks (26.0–31.8 weeks) during the first five days of life. The mean recording time was 130 min. The aEEGs were assessed by pattern recognition, by calculating Burdjalov score, and by calculating the mean values of the 5th, 50th, and 95th centiles of the aEEG amplitudes. Illness severity was determined within the first 24 h.ResultsWe assessed 151 recordings and found strong correlations between the 5th and 50th amplitude centiles and the Burdjalov scores (r = 0.71, p < 0.001 and r = 0.47, p < 0.001, respectively). The 5th and 50th amplitude centiles correlated with SNAP-II (r = − 0.34, p < 0.0001 and r = − 0.27, p = 0.001). These correlations were the strongest on the first day of life (r = − 0.55, p = 0.005 and r = − 0.47, p = 0.018, respectively). The 5th and the 50th amplitude centiles were best predicted by gestational age, SNAP-II, and low blood pressure.ConclusionsSevere illness as measured by the SNAP-II, and low blood pressure had a negative influence on the aEEGs of preterm infants.