Experimental neonatal respiratory failure induced by lysophosphatidylcholine: effect of surfactant treatment

The purpose of this study was to characterize the toxic effects of lysophos phatidylcholine (lyso-PC) on neonatal lung function. Various doses of lyse- PC (from 0 to 40 mg/kg) were administered to near-term newborn rabbits. Lun g-thorax compliance during mechanical ventilation was significantly decreas ed by doses greater than or equal to 10 mg/kg, and static lung volumes duri ng deflation were decreased by doses greater than or equal to 20 mg/kg. Usi ng the same experimental model, we investigated the effects of modified por cine surfactant (Curo-surf, 200 mg/kg). Animals exposed to lyse-PC at birth and treated simultaneously with surfactant showed a satisfactory therapeut ic response, whereas those treated after 30 min failed to respond. These an imals also had a much larger leak of albumin into the air spaces and an ele vated minimum surface tension of the lavage fluid in a pulsating bubble sur factometer, suggesting inactivation of the exogenous surfactant. Timing of surfactant administration may thus be essential for the therapeutic effect in this experimental model of acute lung injury.