Respiratory

Question 1

The lungs have a dual blood supply, bronchial arteries and pulmonary arteries. Where do the bronchial arteries arise and which lung tissues are supplied by the bronchial arteries?

Answer 1

High pressure, low flow bronchial arteries arise from the descending thoracic aorta and supply systemic arterial blood to bronchi and bronchioles, terminating at the respiratory bronchioles. The bronchial arteries also supplied the supporting tissues of the lungs, including nerves, pulmonary vessels, and visceral pleura.

Question 2

The lungs have a dual blood supply bronchial arteries and pulmonary arteries. Where do the pulmonary arteries arise and what lung tissues are supplied by pulmonary arteries?

Answer 2

The low pressure, high flow pulmonary arteries supply venous blood flow to the structures distal to the terminal bronchioles, including distal non respiratory tissues and the alveolar capillary’s where gas exchange occurs. The pulmonary artery arises from the right ventricle and branches into the right and left pulmonary arteries, which further branch to accompany the bronchi.

Question 3

Describe the venous drainage of the lung.

Answer 3

The venous drainage of the bronchi occurs through the bronchial, azygous, hemiazygos, and intercostal veins, which then drain into brachiocephalic veins of the neck and ultimately the superior vena cava. The pulmonary circulation returns to the heart via the pulmonary veins, which empty into the left atrium.

Question 4

What volume of air will fill the tracheal and bronchial cuffs of a double lumen tube?

Answer 4

The tracheal cuff of a double lumen tube normally requires 5-10 mLs air and can accommodate up to 20 mLs of air. Inflation of the double lumen tube bronchial cuff requires 1-2 mLs of air. The bronchial cuff is checked with a 3 mL syringe, but rarely will the bronchial cuff require greater than 2 mLs to create an adequate seal.