Abstract 1737 Neonatal Pulmonology II: Oxidant and Inflammatory Lung Injury Poster Symposium, Tuesday, 5/4

INTRODUCTION: Pulmonary hemorrhage is a serious complication in infants with hyaline membrane disease. To our knowledge, measurement of inflammatory mediators in this condition have not been performed. METHODS: Sequential tracheal aspirates (TA) were obtained from 44 ventilated infants with birth weight less than 1250 grams during the first 21 days of life. Interleukin-8 (IL-8), monocyte chemoattractant protein-1 (MCP-1) and secretory component were measured by ELISA. TA cytokine concentrations were normalized to secretory component. Statistical comparisons between cytokine concentrations obtained from infants with (n=12) and without (n=32) PH were made by ANOVA. Comparisons between clinical characteristics were made using Chi Square, Student t-test or Wilcoxon Rank Sum tests where appropriate. RESULTS: Infants with and without PH were of similar gestation (25.1±0.4 vs. 25.8±0.2 wks; p=0.052) but slightly lesser birth weight (694±32 vs 808 ±27 g; p=0.022). BPD developed in 12/12 infants with PH and 20/32 infants without PH (p=0.013) PH was associated with increased duration of mechanical ventilation (25±3 days vs. 72±27 days, p=0 0007.) and supplemental oxygen therapy (46±5 vs. 110±36, p=0.0096). TA concentrations of IL-8 and MCP-1 were significantly higher in infants with PH (p<0.001 by ANOVA) during the first 21 days of life. Maximum IL-8 concentrations in both infants with and without PH were observed on day 3, whereas maximal concentrations of MCP-1 occurred on day 7. (TA cytokine concentrations are expressed as pg/ug secretory component) (Table) CONCLUSIONS: Infants who have PH have increased concentrations of IL-8 and MCP-1 in tracheal aspirates. These pro-inflammatory cytokines may contribute to the increased lung injury and poor prognosis of infants with PH.

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