Effect of aerosolized dipalmitoyl lecithin on oxygen-toxic rat lungs.

Pulmonary surfactant is reduced in oxygen toxicity but whether this represents a decrease in production or inactivation of surface-active material already present is not known. We divided 200 g male Wister-Lewis rats into different experimental groups. The animals were exposed continuously to 0, 48, 56 or 72 h of close to 100% oxygen at atmospheric pressure. Administration of aerosolized dipalmitoyl lecithin (DPL) in phosphate buffer had no effect on lung deflation compliances or lung stability indices of any group. Exposure to DPL by spontaneous respiration and/or controlled ventilation made no difference. Lung dry/wet weight ratios fell in animals exposed to aerosols of DPL + buffer + O2, buffer + O2, or water + O2, to aerosols of DPL + buffer + O2, buffer + O2, or water + O2, as compared to animals with similar lengths of oxygen exposure not exposed to an aerosol. If the initial pulmonary pathophysiological response to 100% oxygen at 1 atm pressure is capillary logical response to 100% oxygen at 1 atm pressure is capillary endothelial damage with leakage of intravascular fluids into the alveoli, then exogenously administered DPL would not be of benefit in pulmonary oxygen toxicity. Our study suggests that aerosolized DPL administered to normal animals and animals exposed to oxygen for 48-72 h had no effect on lung compliance or stability.