Lung Albumin Recovery in Surfactant-treated Preterm Ventilated Lambs

Preterm ventilated animals and infants with respiratory distress syndrome (RDS) develop proteinaceous alveolar edema. To study the effect of postnatal age on intravascular radiolabeled albumin accumulation into lungs, preterm lambs at 132 days gestatlonal age were ventilated after treatment with sheep surfactant or cow surfactant extract for periods as long as 24 h. Lambs not treated with surfactant were studied for only 5 h because of severe respiratory failure. All lambs were given radiolabeled albumin by intravascular injection 1 h before they were killed, and the net recovery of the labeled albumin was measured in the lung tissue and air space as quantified by alveolar lavage. Net 1-h radiolabeled albumin recoveries in the lungs decreased from 5 to 6% soon after birth to 0.9% at 24 h in the surfactant-treated groups (p < 0.01). At 3 h there was less labeled albumin recovery by alveolar lavages in lambs treated with sheep surfactant than in control lambs and lambs treated with cow surfactant extract (p...