Where it is
In the thoracic cavity on either side of the mediastinum, from about 2–3 cm above the clavicles down to the diaphragm. Each lobe is divided into bronchopulmonary segments.
What it does
Bring air and blood close together across about 70 m² of alveolar surface so oxygen and carbon dioxide can be exchanged.
Clinical relevance
- Atelectasis (collapsed alveoli) is common after surgery and is prevented by deep breathing and early mobility.
- Crackles suggest fluid in the alveoli (pneumonia, heart failure); wheezes suggest narrowed airways.
- The lung bases are posterior and lowest, which is where fluid collects first.
Nursing focus
- Auscultate the posterior bases, where early crackles are heard first.
- Use an incentive spirometer 10 times per hour while awake after surgery.