What is traumatic wet lung?

The lungs are one of the important organs of the human body. The lungs are located in the chest cavity and are closely related to human breathing. The lungs mainly carry out gas exchange, absorb fresh air, and expel foul air from the body to create a healthy environment for the body. Generally speaking, lung diseases are big problems and should be taken extremely seriously, but traumatic wet lung is mainly caused by strong external impact. ? Let’s take a look together!

1. Mechanism of disease

Traumatic wet lung is a common type of lung parenchymal injury, which is mostly caused by rapid blunt trauma, such as car accidents, collisions, crushing and falls. The incidence rate accounts for about 30% to 75% of blunt chest injuries, but it is often ignored or missed due to insufficient understanding, insensitive examination techniques or being masked by other chest injuries.

2. Pathogenesis

The pathogenesis of traumatic wet lung is still not fully understood. Most people believe that it is similar to blast lung injury and is caused by strong high-pressure waves. When strong force acts on the chest wall, the volume of the chest cavity decreases, and the increased intrathoracic pressure forces the lungs, causing bleeding and edema of the lung parenchyma; when the external force is eliminated, the deformed chest cavity rebounds, and the moment of generating intrathoracic negative pressure can cause additional damage to the original injured area. The main pathological changes are alveolar and capillary damage, interstitial and intra-alveolar blood infiltration, and interstitial pulmonary edema, which reduce the air content of the lung parenchyma and increase the extravascular water content, resulting in ventilation and gas exchange dysfunction, and increased pulmonary artery pressure and pulmonary circulation resistance. Pathological changes develop progressively within 12 to 24 hours after injury. Pulmonary contusion is often associated with other injuries, such as chest wall fracture, flail chest, hemothorax, pneumothorax, and heart and pericardial injury.

3. Clinical manifestations

Clinical manifestations vary greatly due to the severity and extent of traumatic wet lung. In mild cases, there are only chest pain, chest tightness, shortness of breath, cough and bloody sputum, and scattered rales are heard on auscultation. There are patchy shadows on the chest X-ray (often reported as traumatic wet lung), which can be completely absorbed in 1 to 2 days. Blood gas may be normal. Some people call it pulmonary concussion. In severe cases, there are obvious breathing difficulties, cyanosis, bloody foamy sputum, tachycardia and hypotension. Auscultation reveals widespread rales, decreased to absent breath sounds, or tubular breath sounds. Arterial blood gas analysis is of reference value before hypoxemia is revealed on chest X-ray. Chest X-ray is an important means of diagnosing traumatic wet lung. In about 70% of cases, the changes appear within 1 hour after injury, and in 30% of cases, they may be delayed to 4 to 6 hours after injury. The range may be from a small localized area to one or both sides, and the degree may range from spotty infiltration, diffuse or local spotty fusion infiltration, to diffuse large infiltration or consolidation shadows in one or both lungs. After treatment, it usually starts to be absorbed 2 to 3 days after the injury, and it takes more than 2 to 3 weeks for complete absorption. In recent years, through serial CT examinations, new pathological viewpoints on pulmonary contusion have been proposed. The contusion shown on X-ray films appears on CT films as a laceration of the lung parenchyma and an alveolar hemorrhage surrounding the laceration without any pulmonary interstitial damage.