Correct!
4. Bronchus/alveoli and the pulmonary vein or its branches
For air to end up in the aorta, it has to have entered the left heart first. This was a lung biopsy and the needle in approximation to the aorta.
Air entering the pulmonary arteries would end up getting lodged in a branch of this circulation, but probably would not make its way through the lung past the alveoli, into the pulmonary veins and back to the left heart.
Air entering the bronchial arteries would similarly end up getting stuck in smaller branches and again, it is not likely that the air would go the capillaries between bronchial artery and bronchial veins then end up in the right sided systemic circulation. If it did, the only way it could get into the aorta would be a right to left intra-cardiac shunt.
Air entering the pulmonary veins would get back to the left atrium and thence into the systemic circulation.
Air entering the bronchial veins would end up in the azygos vein on the right side or the hemiazygos vein on the left side and thence into the superior vena cava and right atrium, thence back into the right ventricle and pulmonary arteries. Without a right to left shunt, such air should not end up in the left side of the heart.
It is possible that air could have entered from the biopsy needle rather than from a bronchus or alveoli, but is less likely because the appropriate biopsy technique keeps fluid in the syringe at all times and gentle continuous suction to prevent this very event from occurring.
What is the ideal patient positioning for such a complication? (Click on the correct answer to be directed to the fourth of six pages)