Risk factors of neurologic sequelae in full-term newborns with perinatal asphyxia

Introduction. Perinatal asphyxia (PA) and its neurologic manifestations are the most important cause of brain injury and neurologic sequelae in full-term infants. The objective of this study is to analyze the perinatal risk factors of neurologic sequelae in asphyctic term newborns. Patients and methods. One hundred and fifty-six consecutive asphyctic term infants were studied prospectively during 40 months. PA was graded in two stages (severe and non-severe), hypoxic-ischemic encephalopathy classification was based on Levene's criteria, and neurologic sequelae was based on Finer and Amiel-Tisson's criteria. The perinatal variables were graded as prenatal (gestational and obstetrics), neonatal (resuscitation, general data of the newborn, and organic manifestations of asphyxia) and postneonatal (neurologic sequelae with at least 24 months of follow-up). The relationships between these variables are studied by univariant and multivariant analysis (Cox's regression). Results. PA was graded as severe in 31 cases and non-severe in 125. Neurologic manifestations (hypoxic-ischemic encephalopathy) during neonatal period were present in 25.6%, and extraneurologic manifestations (hypoxic-ischemic disease) in 41.7% cases. The incidence of neurologic sequelae, in 115 asphyxiated full-term infants follow-up at least 24 months, was 16.5% (19 cases). The perinatal variables associated to risk of neurologic sequelae on univariate analysis are variables of neonatal resuscitation (1 minute Apgar score less than or equal to 4, 5 minute Apgar scope less than or equal to 6, endotracheal intubation, severity of PA) and variables of systemic manifestations (hypoxic-ischemic encephalopathy, cardiovascular and multisystemic dysfunction, and mechanical ventilation). But only two variables are independently associated on multivariate analysis: severe PA (RR= 2.82; IC= 1.07-7.39) and hypoxic-ischemic encephalopathy (RR= 4.17; IC= 1.48-11.75). Conclusions. The best predictive risk factors for the neurological prognosis at follow-up are severe PA at birth and/or evidence of encephalopathy in neonatal period.