245 Prediction of Cerebral Outcome at 24 Months in Preterm Infants by NIRS in The First 24 Hours After Birth

Abstract

Background: The prognostic value of cerebral NIRS in preterm infants remains controversial. Impaired autoregulation of brain perfusion quantified as high coherence between oscillations of cerebral intravascular oxygenation and arterial blood pressure in sick preterm infants has been related to intracerebral haemorrhage and hypoxic ischemic encephalopathy (Tsuji 2000).Aim: To compare cerebral NIRS parameters during the first 24 hours of life in sick preterm infants with cerebral ultrasound findings and neurological outcome at 9 and 18 months. Patients: 31 preterm infants admitted to our NICU for respiratory distress. Gestational age ranged from 26 1/7 to 32 2/7 weeks (median: 27 2/7) and birth weight from 690 to 2440 g (median: 1030 g).Methods: Total haemoglobin (tHb) and oxygenaton index (OI) was measured with NIRS using a sensor placed frontoparietally at three time points: 1) within first 6 h, 2) 12 - 16 h and 3) 24–28 h. Heart rate, arterial blood pressure (MAP), arterial oxygen saturation and transcutaneous pO2 and pCO2 were recorded simultaneously. Cerebral ultrasound examination (Acuson 128XP, 7 MHz transducer) was performed at 12 to 24 hours of life, at days 3, 7, 14 and every two weeks until discharge. Psycho-motor-developmental index (Bayley, PDI), mental-developmental index (MDI) and the neurological status were assessed in all surviving infants at nine and 18 months corrected for prematurity. A late follow-up examination was done between 3 and 10 years.Results: Nine infants died within the first 10 days. Nine months after expected date of birth 10 out of 20 survivors were classified abnormal with MDI or PDI <85. (Parents of two infants refused the examination). At 18 months corrected for prematurity 3 out of 18 infants had abnormal neurological status. Coherence between OI or tHb and MAP or heart rate did not change significantly between the three session. Intact survivors had significantly higher coherence with 0.6 (IQR 0.38– 0.84) than survivors with abnormal neurological status 0.38 (IQR 0.24–0.52) and deaths 0.28 (IQR 0.24–0.52).Conclusion: In contrast to previous studies low coherencies in the first 24 hours were associated with intraventricular haemorrhage, death or abnormal neurological outcome at 18 months or later. Consistent predictive results are obtained with coherencies between MAP or HR and OI or tHb analysed at 6, 12 and 24 hours after birth.