Plasma concentration of elastase-alpha 1-proteinase inhibitor complex in surfactant-treated preterm neonates with respiratory distress syndrome.

Although exogenous surfactant replacement improves respiratory distress syndrome (RDS) of immature neonates, it may not prevent subsequent lung damage and development of bronchopulmonary dysplasia associated with polymorphonuclear neutrophil (PMN)-activation. We therefore wanted to assess whether surfactant administration would be associated with activation of circulating PMNs. Since elastase-alpha 1-proteinase inhibitor (E-alpha 1-PI) has proved to be a sensitive indicator of intravascular PMN activation, we studied E-alpha 1-PI plasma concentration in preterm neonates during the treatment of RDS with a bovine surfactant preparation (group I: n = 23). Results were compared with those from a retrospective control group treated by ventilation alone (group II: n = 13), and with a reference group of 92 newborns (group III). Following surfactant administration, median E-alpha 1-PI concentration increased significantly (day 1 80.5 vs Day 2,234 micrograms.l-1), and exceeded the upper limit of the reference range of 274 micrograms.l-1 in seven patients, with a maximal value of 1,881 micrograms.l-1 after multiple surfactant administrations. In contrast, 12 infants from Group II showed no increase in median E-alpha 1-PI levels (Day 1,107 vs Day 2,107 micrograms.l-1), and remained within the reference range (Day 1,125 micrograms.l-1; Day 2,107 micrograms.l-1) of the 92 newborns without respiratory impairment, infection, birth-trauma or asphyxia. From these results, it is concluded that surfactant may trigger a transient, mainly local, inflammatory response, reflected by increased levels of E-alpha 1-PI, and may exert a dose-related pathogenic influence on the course and prognosis of RDS.(ABSTRACT TRUNCATED AT 250 WORDS)