Physiologic Sufficiency of Regenerated Lung Lymphatics

The physiologic sufficiency of regenerated lung lymphatics after surgical transection of the lung hilum was studied experimentally. Dogs were prepared by surgical interruption of all left lung hilar tissues and structures except the skeletonized pulmonary artery and the pulmonary veins; continuity of the bronchus was restored by anastomosis. Anatomic reconnection of lung lymphatics to mediastinal lymph vessels was determined by injecting a sky blue dye marker into peribronchial tissues distal to the bronchial anastomosis at different intervals after surgical preparation. From a series of 50 experimental animals it was demonstrated that the surgical procedcure interrupted lymphatic drainage and that anatomic reconnection with mediastinal lymphatics developed 7-28 days after preparation. Physiologic sufficiency of regenerated lymphatics was studied in 60 animals by rapid intravascular volume expansion as a test of lymph flow capacity. By gravimetric determination of lung water and histologic examination of lung specimens this study revealed a significant incapacity to maintain lung water homeostasis 3 days after preparation with return toward normal lymph flow capacity 35 days after preparation. This study indicated that lung lymphatic drainage is re-established 7--28 days after surgical interruption and becomes relatively sufficient after 35 days.