RESPIRATORY FUNCTION AND BLOOD FLOW IN THE BRONCHIAL ARTERY AFTER LIGATION OF THE PULMONARY ARTERY

Abstract

In the dog, a lung with a ligated pulmonary artery can maintain a respiratory function. The capacity of such a lung to absorb O2 gradually increases over a period of months. When O2 rather than air is supplied through a bronchospirometric cannula, while the intact lung continues to breathe air, the O2 content of the arterial blood increases. The effective flow in the bronchial arteries of such a lung increases with time after ligation, as measured by bronchospirometry and an application of the Fick principle. The increase in circulation is in step with the expansion of the vasular bed demonstrated in anatomical studies by the vinylite method as reported elsewhere. After the 4th month with the animal under Na pentobarbital anesthesia, the flow usually exceeds 1 l/m2/min. This flow is largely a burden on the left heart whose output becomes roughly 33% greater than that of the right. A similar situation obtains in human disease, such as bronchiectasis or congenital pulmonic stenosis, where there is an extensive collateral circulation to the lungs.