Respiratory failure following anti-lung serum: study on mechanisms associated with surfactant system damage

Within 2 minutes intravenous anti-lung serum (ALS) into guinea pig induces a respiratory failure that is fatal within 30 min. The relationship between surfactant, alveolar-capillary permeability and respiratory failure was studied. Within two minutes ALS induced a leak in the alveolar-capillary barrier. Within 30 minutes 28.3% (controls, given normal rabbit serum: 0.7%) of iv 131I-albumin, and 0.5% (controls 0.02%) of iv surfactant phospholipid tracer were recovered in bronchoalveolar lavage. Furthermore, 57% (controls 32%) of the endotracheally administered surfactant phospholipid became associated with lung tissue and only less than 0.5% left the lung. The distribution of proteins and phospholipids between the in vivo small volume bronchoalveolar lavages and the ex vivo bronchoalveolar lavages were dissimilar: 84% (controls 20%) of intravenously injected, lavageable 131I-albumin and 23% (controls 18%) of total lavageable phospholipid were recovered in the in vivo small volume bronchoalveolar lavages. ALS also decreased lavageable surfactant phospholipid by 41%. After ALS the minimum surface tension increased. The supernatant of the lavage increased the minimum surface tension of normal surfactant. In addition, the sediment fraction of the lavage had slow surface adsorption, and a marked reduction in 35,000 and 10,000 MW peptides. Exogenous surfactant ameliorated the ALS-induced respiratory failure. We propose that inhibition, altered intrapulmonary distribution, and dissociation of protein and phospholipid components of surfactant are important in early pathogenesis of acute respiratory failure.