Histologic results of the placenta are usually not available within the first days of life. We identified inflammatory variables in tracheal aspirates and blood that were associated with histologic chorioamnionitis (HC). A derivation cohort consisted of 62 neonates and a validation cohort of 57 neonates with a gestational age Ͻ 31 wk and ventilated on d 1. Tracheal aspirates were taken on d 1 and on d 3, if the patient was still ventilated. HC was diagnosed by light microscopy. Logistic regression was used to identify independent factors in the derivation cohort associated with HC at d 1, 2, and 3. Model performance was studied using receiver operating characteristic curve analysis. Independent factors associated with HC were, at d 1, tracheal aspirate IL-8 Ն 917 pg/mL (odds ratio, 60.7; 95% confidence interval, 11-328); at d 2, blood C-reactive protein Ն 14 mg/L (odds ratio, 9.2; 95% confidence interval, 2-38), blood white blood cell count Ն 10,400/mm 3 (odds ratio, 7.4; 95% confidence interval, 2-28); and at d 3, blood neutrophil count Ն 4968/mm Chorioamnionitis is considered to be one of the main causes of preterm labor and has been associated with an adverse perinatal outcome (e.g. cerebral palsy and chronic lung disease) in preterm infants (1, 2). Histologic results of the examination of the placenta are usually not available within the first days of life, and prenatal diagnosis of chorioamnionitis remains difficult. An early diagnosis is difficult and can only be made in 6% to 24% of these patients by amniotic fluid culture (3). As a result of the "chronic inflammation" of fetal or maternal membranes, elevated proinflammatory cytokine levels are found in the amniotic fluid and ultimately in the fetus. These cytokines are associated with preterm labor and delivery, a fetal inflammatory response, and the associated negative outcomes (4, 5).The objective of the present study was to identify variables in the TA and blood of preterm infants, measured within the first 3 d of life, that are associated with HC in the placenta. These factors would allow us to identify infants with the highest risk of suffering from the adverse consequences of chorioamnionitis.
METHODS
Study population.