Neurological maturation of late preterm infants at 34 wk assessed by amplitude integrated electroencephalogram

BACKGROUND: This study tested if measures of central nervous system (CNS) immaturity reflected by amplitude integrated electroencephalogram (aEEG) and associated clinical morbidities are determinants of length of hospitalization among late preterm infants born at 34 wk. METHODS: This was a prospective cohort study of infants with a gestational age of 34 wk 0-6 d who had a single aEEG recording acquired over 6 h in a neonatal intensive care unit within 72 h of birth (n = 80). Infants were followed for pre-defined morbidities (classified as CNS or non-CNS) and length of hospitalization (determined by the clinical care team). aEEG variables were correlated with length of hospitalization. RESULTS: Eighty infants were enrolled and 75 aEEG recordings were analyzed. The average length of hospitalization was 10.4 +/- 7.2 d (range 3-46 d). The total number of cycles recorded in the first 72 h following birth were inversely correlated with the length of hospitalization (r(2) = 0.44, P < 0.001). Kaplan-Meier curves indicated that morbidities consistent with neurological immaturity were associated with a longer length of hospitalization (P < 0.001). CONCLUSION: Neurological maturation as indicated by aEEG and specific clinical morbidities is an important determinant of length of hospitalization among late-preterm infants.