Pulmonary aeration after unilateral fetal ligation of pulmonary artery in neonatal rabbits.

When the pulmonary artery was ligated at the gestational age of 30 days, 9 out of the 17 rabbit fetuses had vital lungs and in 7 of these the lungs were aerated after breathing for 15 min to 1 h. Ligation before this gestational age caused necrotic lungs in all 13 rabbit fetuses. On the basis of this we can conclude that the bronchial circulation is not sufficient to ensure vitality of the fetal lung and the pulmonary circulation does not play a major role in the primary aeration of the lungs at birth.