Induction of lipid peroxidation of pulmonary surfactant by plasma of preterm babies

Respiratory distress syndrome of the preterm baby is believed to be caused by a deficiency of pulmonary surfactant and leakage of plasma into the alveolar spaces. Since the two pathogenetic factors seem to be inter-related, we postulated that peroxidation of surfactant by plasma iron could be the linking mechanism. We obtained cord blood samples from 22 preterm babies (mean gestational age 32·2 [SD 2·7] weeks) and 24 term babies (40·1 [1·6] weeks), and venous blood samples from 18 healthy adults. No adult had detectable non-protein-bound iron in the plasma, but 10/21 (48%) preterm babies and 6/24 (25%) term babies had detectable concentrations (rate difference 23% [95% Cl -5 to 51%], p=0·20). Transferrin and haptoglobin concentrations were higher and free haemoglobin concentrations lower in adults than in babies (p