An Experimental Method for the Radiographic Demonstration of the Bronchial and Pulmonary Arteries

In a previously described series of experiments 1 it was found that the introduction into the venous circulation of an embolus infected with pyogenic organisms may be followed by widely differing pathological changes in the parenchyma of the lung. To determine the exact conditions present within the pulmonary and bronchial circulations following the introduction of such emboli a method for the radiographic demonstration of the two circulations was developed.

Anatomically the bronchial arterial system usually arises as one or more branches from the first portion of the descending aorta anteriorly. Occasionally branches may arise from the first or second intercostal, the internal mammary, or the right subclavian arteries. They enter the lung at the hilum and course along the bronchi and their branches up to the ductus alveolaris. 2

The bronchial artery is best injected with the lung in situ. Under chloroform or ether anaesthesia the chest is opened avascularly by splitting the sternum exactly in the midline. Just before entering the pleural cavity the animal is killed with the anaesthetic to prevent injury to the inflated lung.

The innominate and left subclavian arteries are ligated as they leave the aortic arch. The first intercostal arteries should be clamped laterally to avoid occlusion of the bronchial artery which may arise from one of them. The thoracic aorta is tightly clamped distal to the fifth intercostal arteries so as to limit the injection to the thorax.

The pericardium is opened longitudinally and a large cannula inserted into the aorta through an incision in the left ventricle, all air is excluded from the system by filling the cannula and the attached tube with warm water before insertion into the ventricle. A heavy ligature passed around the base of both the aorta and pulmonary artery holds the cannula firmly with less danger of rupture of the aorta by cutting through of the ligature.