Cerebral function monitoring in neonates with perinatal asphyxia--preliminary results.

INTRODUCTION: This study was based on foreign studies which confirmed the importance of amplitude-integrated electroencefalographic monitoring (aEEG) in the early prediction of the future neurological development of newborn infants with hypoxic syndrome. Our aim was to confirm the correlation between the type of aEEG trace and the level of brain damage in newborn infants in the early hours after the hypoxic event and to introduce this method into routine practice.

MATERIAL AND METHODS: With 56 newborn infants having suffered a perinatal hypoxic event (the average umbilical arterial pH was 6.95, the average BE value -17.3) and in 2 newborn infants after early postnatal hypoxia, aEEG monitoring was performed continually. The aEEG records of brain activity obtained were analyzed using the Hellström-Westas classification. The level of hypoxic-ischemic encephalopathy was evaluated according to the Sarnat-Sarnat classification. Assessment of future neurological development is not included in this work.

RESULTS: 12 (21%) of the 56 newborn infants did not develop any hypoxic-ischemic encephalopathy, 8 (14%) newborn infants had hypoxic-ischemic encephalopathy (HIE) grade I, 19 (35%) had HIE grade II and 17 (30%) had HIE grade III. The newborn infants without hypoxic-ischemic encephalopathy had normal or slightly abnormal aEEG trace. In the case of newborn infants who had HIE grade I, we recorded a normal or slightly abnormal aEEG trace. In the case of newborn infants who had HIE grade II, we recorded all types of aEEG trace--from normal to seriously pathological. Of the newborn infants who had HIE grade III, all had a pathological aEEG trace of "burst suppression patterns", low voltage pattern or flat trace pattern. The results show that if a newborn infant had a pathological type of aEEG trace in the early hours after a hypoxic event he or she later developed at least HIE grade II. 53% of the newborn infants with a flat aEEG trace later had HIE grade III.

CONCLUSION: Cerebral function monitoring is a non-invasive method used for the early assessment of the severity of a hypoxic event. As it could be used in the first few hours after birth, this method could be applied to select patients suitable for therapeutic hypothermia.