Drainage routes of bronchial blood flow in anaesthetized sheep

Abstract The systemic circulation to the lung supplies the trachea and airway walls and may be important in the pathophysiology of asthma and pulmonary oedema. An understanding of the venous drainage pathways of this bronchial blood flow may be therapeutically important. The purpose of this study was to understand the normal drainage pathways in sheep. In seven anaesthetized, ventilated sheep we injected echo contrast agents into a systemic vein or into the bronchial artery while performing echocardiography to determine whether the drainage could be observed to the right heart and/or to the left heart. During transoesophageal echo ( n = 5 ) or heart surface echo ( n = 2 ), cephalic vein injection of