Lung consolidation is a condition where the air in the small airways of the lungs is replaced with a fluid, solid, or other material such as pus, blood, water, stomach contents, or cells. This condition can be caused by various factors, including pneumonia, pulmonary edema, and lung cancer. Consolidation almost always makes it difficult for a person to breathe, as air cant get through the consolidation, and the lung cant do its job of bringing in fresh air and removing the air the body has used. Some of the symptoms of lung consolidation include coughing up thick green or bloody sputum, coughing up blood, a dry cough, breathing that sounds funny or is noisy, chest pain or heaviness, rapid breathing, fever, and fatigue.

Consolidation occurs through the accumulation of inflammatory cellular exudate in the alveoli and adjoining ducts. The liquid can be pulmonary edema, inflammatory exudate, pus, inhaled water, or blood (from bronchial tree or hemorrhage from a pulmonary artery). Consolidation must be present to diagnose pneumonia, and the signs of lobar pneumonia are characteristic and clinically referred to as consolidation.

Ultrasound can distinguish consolidated lung from effusion and can be essential prior to performing a thoracentesis to determine if there is sufficient fluid to be tapped. In consolidated lung, as fluid fills the lung and displaces air, the lung is easier to visualize with ultrasound. In some cases, complex effusions can be more difficult to distinguish, but air bronchograms (small bright reflectors from air trapped in the lung) or doppler can be used to visualize small pulmonary vessels.