OVERVIEW

What is lung injury?

Lung injury, as the name suggests, primarily refers to damage to lung tissue.

It includes various injurious factors such as severe chest trauma, inhalation of harmful substances (toxic gases, gastric contents, seawater, etc.), and severe lung infections that cause damage to lung tissue, leading to the destruction of structural integrity or functional impairment of the lungs.

SYMPTOMS

What are the main manifestations of lung injury?

Symptoms vary depending on the severity and extent of the injury. Mild cases may only present with chest pain, chest tightness, shortness of breath, and bloody sputum, while severe cases may exhibit significant dyspnea, cyanosis, frothy bloody sputum, tachycardia, and hypotension.

What abnormalities can occur with lung injury?

Possible complications include pulmonary hematoma, traumatic wet lung, hemothorax, pneumothorax, traumatic asphyxia, cardiac and major vascular injuries, cardiac tamponade, massive blood loss, and hypotension.

What is a pulmonary hematoma?

During lung injury, blood leaks into the alveoli and pulmonary interstitium due to various causes, leading to retraction of surrounding lung tissue, which is referred to as a pulmonary hematoma.

Patients with pulmonary hematoma often experience chest pain, hemoptysis, low-grade fever, and dyspnea, which typically resolve within about a week.

What is traumatic wet lung?

Traumatic wet lung is very common in chest trauma and primarily results from injury to the lung parenchyma, causing pulmonary hemorrhage and edema, which impair normal respiratory function. It often progresses within 12–24 hours after trauma.

Symptoms of traumatic wet lung vary in severity, with severe cases presenting dyspnea, cyanosis, and frothy bloody sputum.

What are hemopneumothorax and tension pneumothorax?

• Hemopneumothorax:

  • Hemopneumothorax refers to the accumulation of blood and air in the pleural cavity following chest trauma. Since this occupies the normal respiratory and circulatory space in the chest, it can lead to dyspnea and even affect blood circulation.
  • Hemopneumothorax occurs in about 70% of chest trauma cases. Small amounts may resolve on their own, but massive hemopneumothorax is one of the leading causes of death in chest trauma.

• Tension pneumothorax:

  • Tension pneumothorax occurs when external air continuously enters the pleural cavity due to lung injury and cannot escape, increasingly compressing normal lung tissue. This leads to worsening dyspnea and impacts cardiac function and circulation. Without emergency intervention, the condition can become life-threatening.

What is traumatic asphyxia?

Traumatic asphyxia is relatively rare in chest trauma and mainly affects children and adolescents, typically caused by crushing injuries such as collapses, severe car accidents, or stampedes.

Traumatic asphyxia results from a sudden increase in intrathoracic pressure due to blunt chest trauma, compressing the heart and major veins, causing blood to reflux and leading to overfilling and rupture of peripheral veins and capillaries.

Patients often exhibit purplish-blue bruising on the face, neck, and upper chest, along with restlessness, dizziness, or even limb convulsions.

What signs indicate worsening conditions in chest trauma patients with lung injury?

• Blood pressure: Persistent or progressive hypotension.
• Respiration: Increasing dyspnea or even respiratory distress.
• If any of these signs occur, the patient may be at immediate risk of life-threatening complications.

CAUSES

What are the main causes of lung injury?

• Trauma: Severe blunt force injuries, such as car accidents, impacts, crushing, stampedes, mudslides, falls, and combat wounds.

• Lung diseases: Diffuse severe lung infections, aspiration pneumonia (e.g., inhalation of gastric contents, toxic gases, high-concentration oxygen, seawater, etc.), pulmonary embolism, lung surgery, etc.

• Systemic diseases: Systemic inflammatory response syndrome, sepsis, excessive fluid (or blood) infusion, metabolic disorders, and other conditions can also cause lung injury.

How does lung injury usually occur?

• External force causes rib fractures, and the sharp broken ends of the ribs directly puncture the lungs. The wound edges are relatively neat, resembling a knife cut. The severity of the injury varies, and so do the symptoms.

• When the chest is subjected to external compression with the glottis closed, the pressure inside the lungs suddenly increases. As the pressure subsides and the chest returns to its original shape, the pressure inside the chest cavity drops sharply. This instantaneous change in pressure creates a pressure difference, leading to lung rupture. Such wounds are often irregular, jagged, and frequently involve multiple tears.

• Severe lung infections, aspiration, and systemic inflammatory responses cause diffuse damage to the alveolar and capillary membranes, leading to lung tissue edema and hemorrhage, which further impair lung gas exchange function.

DIAGNOSIS

What tests are generally required after a lung injury occurs?

• The doctor will take a detailed medical history and perform a physical examination.

• Chest imaging tests: including X-rays, chest CT scans, etc.

• For patients with difficulty breathing, an urgent blood gas analysis is needed to assess the extent of respiratory impairment caused by the lung injury, such as hypoxia.

• Other tests may be conducted to check for injuries outside the lungs.

Why do lung injury patients need both chest X-rays and chest CT scans?

Chest X-rays are simple and convenient and often provide a better overview of the chest and rib fractures compared to chest CT scans.

Chest CT scans have higher resolution and can perform rib reconstruction, allowing for a clear observation of the location, nature, and severity of lung injuries. They improve the detection rate and accuracy of lung injuries and rib fractures and help identify hidden complications in a timely manner.

Combining both tests in the diagnosis and treatment of lung injuries can prevent missed or misdiagnosed cases, saving critical time for patient care.

Why do lung injury patients need extensive additional tests?

In addition to the lungs, the chest contains vital organs such as the heart and major blood vessels. Severe lung injuries are often accompanied by damage to these structures.

Therefore, for lung injury patients suspected of having other complications, comprehensive additional tests are necessary for accurate diagnosis.

TREATMENT

How to Treat Lung Injury?

The general principles of treatment are: eliminating the underlying cause of lung injury, supporting respiration, improving blood circulation and oxygen supply, preventing complications, and protecting the function of vital organs.

• Eliminating the underlying cause of lung injury: For example, lung injury caused by severe pulmonary infection requires active anti-infection treatment, including adequate drainage of the infection site, effective debridement, and rational use of antibiotics.

• Respiratory support: Oxygen therapy is the most common method. In severe cases, mechanical ventilation may be required.

• Suppressing excessive inflammatory response: Immunomodulatory drugs or corticosteroids may be used to prevent excessive inflammatory reactions that could further damage the body.

• Maintaining fluid balance: In cases of significant blood loss, blood transfusion or fluid infusion is needed to maintain sufficient cardiac output. However, fluid intake should be strictly limited when blood pressure is normal to avoid worsening pulmonary edema.

• Nutritional support: Ensuring adequate nutrition to facilitate the body's gradual recovery.

• Preventing complications and protecting vital organ function.

Why Are Monitoring Devices Used After Hospitalization for Lung Injury?

Monitoring devices are primarily used to track the patient's heart rate, respiration, blood pressure, and oxygen saturation—all critical vital signs that reflect the stability of the condition and potential life-threatening risks.

Within 12–24 hours after lung injury, the condition is often unstable, manifesting as decreased oxygen saturation, increased heart rate, rapid breathing, and lowered blood pressure, all of which are directly displayed on the monitor.

Therefore, patients with severe lung injury generally require cardiac monitoring upon hospitalization to help doctors assess the condition promptly and provide emergency treatment. The monitor can be removed once the condition stabilizes.

What Critical Conditions May Occur After Lung Injury? How Will Doctors Handle Them?

• Persistent drop in blood pressure: If blood pressure continues to fall, chest tube drainage exceeds 300 mL per hour after hemopneumothorax drainage, or cardiac tamponade is suspected, it indicates ongoing severe bleeding. Doctors will perform emergency thoracotomy for hemostasis while administering rapid fluid infusion, blood transfusion, hemostatic drugs, and vasopressors.

• Tension pneumothorax: This can cause severe dyspnea or even suffocation. In emergencies, doctors may use a large needle to puncture the chest wall and release gas to reduce intrathoracic pressure. If medical equipment is available, a "closed thoracic drainage" procedure will be performed to remove gas and accumulated blood from the pleural cavity.

• Severe flail chest: Often seen in cases of multiple rib fractures, leading to paradoxical chest wall movement and severely impaired breathing. Doctors will perform endotracheal intubation and connect the patient to a ventilator.

• Acute airway obstruction: Caused by blockage of the respiratory tract, resulting in difficulty inhaling, wheezing, or suffocation. In emergencies, doctors may perform a cricothyrotomy to open the airway and allow oxygen to reach the lungs.

• Open pneumothorax: The chest wall wound is closed, and "closed thoracic drainage" is performed to remove gas and accumulated blood from the pleural cavity.

What Is "Closed Thoracic Drainage" Used for Lung Injury?

"Closed thoracic drainage" is generally used to treat various pleural effusions, hemothorax, and pneumothorax, commonly seen in cases of hemothorax, pneumothorax, or hemopneumothorax.

After local anesthesia, a catheter is placed between the ribs as a drainage tube and connected to a water-sealed drainage bottle containing saline to expel gas or collect pleural fluid. This allows the lung tissue to re-expand and restore ventilation and gas exchange.

After the procedure, a chest X-ray is usually taken to confirm proper placement of the drainage tube. Doctors can assess the patient's condition based on the daily volume of drained fluid, blood, or gas.

Once the condition improves and lung re-expansion is confirmed, the drainage tube can be clamped for observation for over 24 hours. If the patient breathes normally, the tube can be removed, and the chest wall incision is sealed with sterile Vaseline gauze.

Why Are Painkillers Not Immediately Used for Lung Injury Caused by Trauma?

Painkillers are generally avoided before fully assessing the patient's condition to prevent masking symptoms. However, if severe pain affects normal respiratory function or sleep, analgesics may be used as appropriate.

Which Types of Lung Injury Require Emergency Thoracotomy?

Simple localized lung lacerations or contusions are common after chest trauma and usually do not require surgery.

Emergency surgery is needed for progressive hemothorax or uncontrollable hemoptysis caused by severe lung contusion or laceration.

Can Lung Injury Be Cured?

Since the causes of lung injury vary and the severity differs, the prognosis cannot be generalized. Generally, patients with underlying lung diseases or acute respiratory distress syndrome (ARDS) have a poorer treatment outlook.

DIET & LIFESTYLE

What should caregivers pay attention to when caring for patients with lung injury?

• Do not adjust the patient's infusion rate on your own: In some cases, rapid infusion is required, while in others, the infusion rate needs to be controlled. Doctors and nurses will adjust the infusion rate based on the patient's specific condition. Patients and caregivers should not make adjustments without authorization.

• Encourage the patient to cough and expectorate as advised by the doctor: Patients with lung injury often avoid coughing and expectorating due to pain or other reasons. However, coughing and expectoration help clear respiratory secretions, promote infection recovery, and prevent airway blockage by phlegm. Therefore, when the doctor recommends coughing and expectoration, caregivers should actively encourage the patient to comply.

PREVENTION

How to prevent lung injury?

Lung injury is mostly caused by primary diseases or external forces, so the most important way to prevent lung injury is to actively treat the primary disease and avoid external force damage.