Disturbed Surface Properties in Preterm Infants with Pneumonia

Abstract

Congenital pneumonia in preterm infants is often associated with respiratory insufficiency requiring mechanical ventilation. This study was performed to show whether pneumonia in these infants is associated with an inhibition or deficiency of surfactant. The ratio of lecithin and sphingomyelin (L/S ratio) and minimal surface tension were determined in pharyngeal aspirates from 90 term born infants (healthy) and in tracheal aspirates from preterm infants with wet lung (n = 13), congenital pneumonia (n = 21) and respiratory distress syndrome (RDS) (n = 90). The L/S ratio was lower (p < 0.0001) in the RDS group (8.6) when compared with healthy (48.6), wet lung (42.9) and pneumonia (28.9). Surface tension was higher (p < 0.001) in RDS (37 mN/m) and pneumonia (33.7) when compared with healthy (22.9) or wet lung (21.2). For infants with RDS, L/S ratio <16.5 detects surfactant deficiency with 96% specificity and 70% sensitivity, surface tension >29 mN/m represents surfactant inhibition (specificity 97%, sensitivity 92%). Using these cut-off values in infants with pneumonia, 81% had a sufficient amount of surfactant but only 21% of infants with pneumonia had appropriate surface tension. Our study shows that lung effluent of respiratory insufficient infants with pneumonia, who need mechanical ventilation, has disturbed surface properties despite a sufficient amount of surfactant. In these infants, surfactant substitution could be beneficial.

Influence of Partial Liquid Ventilation on Bacterial Growth and Alveolar Expansion in Newborn Rabbits with Group B-Streptococcal Pneumonia

“…This disease is often associated with surfactant dysfunction and respiratory failure requiring mechanical ventilation (32,33). In those infants PLV could be considered an alternative to treatment with CMV, despite the less promising clinical results obtained with PLV in adult patients with ARDS.…”

Neonatal Pneumonia

“…This may cause epithelial injury to the airways, leakage of proteinaceous fluid into the alveoli and interstitium, leading to surfactant deficiency or dysfunction. Data from a German study (9) suggest that respiratory insufficiency in pneumonia is most likely caused by inhibition of surface-tension-lowering properties of surfactant rather than by surfactant deficiency. Important predisposing factors in the evolution of pneumonia are immaturity, low birth weight, premature rupture of membranes, chorioamnionitis and factors associated with prolonged neonatal intensive care (2,8).…”

Current Understanding of Congenital Pneumonia

“…Rudiger et al reported that the lung effluent of these infants had disturbed surface properties despite a sufficient amount of surfactant [39]. Based on their findings, they proposed that surfactant therapy could be beneficial in these infants.…”