Effect of terbutaline on lung mechanics and morphology in the preterm rabbit neonate.

Lung morphology, surface properties of fetal pulmonary fluid, and lung mechanics during spontaneous breathing were studied in preterm newborn rabbits after antenatal administration of terbutaline (0.1 mg). The histological evaluation of lung sections revealed increased amounts of granular eosinophilic and sudanophilic material in the terminal airspaces. The amount of fetal pulmonary fluid was decreased in terbutaline-treated animals; the fetal pulmonary fluid also showed improved surface properties, evaluated by the pulsating bubble technique. Increased dynamic lung compliance without altered air-way resistance was found in terbutaline-treated animals during the first 30 min after onset of breathing. This report demonstrates that terbutaline has an initial beneficial influence on the preterm neonatal lung, probably due to release of preformed surfactant into the alveolar spaces and to dehydration of the lung.