Definition

Atelectasis, also known as lung collapse, refers to the collapse of a part or all of the lung or lung area (lobe). This condition occurs when the air sacs in the lung (alveoli) collapse or become filled with alveolar fluid. It can cause difficulty breathing or shortness of breath, especially in individuals who already have pre-existing lung disease.

Atelectasis is one of the most common respiratory system complications that occur after surgery. Additionally, this condition can also be a complication of other respiratory problems such as cystic fibrosis, lung tumors, chest trauma, accumulation of fluid in the lungs, or foreign objects in the airways.

Causes

Atelectasis occurs due to airway obstruction or pressure from outside the lung (non-obstructive). The most common cause of atelectasis is general anesthesia procedures. These procedures alter your normal breathing pattern and affect air exchange in the lungs, which can result in alveolar collapse. Nearly everyone undergoing major surgery experiences atelectasis, especially after heart bypass surgery.

Causes of obstructive atelectasis:

Several conditions that cause atelectasis due to obstruction include:

• Mucus obstruction: accumulation of mucus in the airways. This commonly occurs during and after surgery because you may not be able to cough. Medications given during the surgical process cause shallow breathing, trapping mucus in the airways. Mucus suctioning during surgery does help clear mucus, but it can still accumulate. Mucus obstruction is also often found in children, patients with cystic fibrosis, and during severe asthma attacks.
• Foreign objects: Atelectasis often occurs in children who insert foreign objects into their nose or mouth, which eventually enter the airways. Common objects swallowed by children include nuts, small toys, buttons, and others.
• Tumors in the airways can compress the airways, making them narrow.

Causes of non-obstructive atelectasis:

Meanwhile, the causes of non-obstructive atelectasis include:

• Chest injuries, such as those from traffic accidents or falls from heights, can cause pain that worsens with breathing. Therefore, due to this pain, breathing becomes abnormal or shallow, leading to lung collapse.
• Pleural effusion or accumulation of fluid in the space between the lung and the chest wall.
• Pneumonia or lung infection, caused by bacteria, viruses, fungi, or other organisms.
• Pneumothorax, or lung collapse, is caused by air leaking into the space between the lung and the chest wall.
• Scar tissue or scar on lung tissue. Scarring can be caused by injury, lung disease, or surgery.
• Tumors outside the airways but near the lungs can compress the lungs and make it difficult for them to expand. These lungs, unable to expand, will collapse.

Risk Factor

Several factors increase the risk of atelectasis, including:

• Advanced age
• Conditions causing difficulty swallowing, such as stroke or other nerve disorders
• Extended bed rest without frequent position changes
• Lung diseases such as asthma, chronic obstructive pulmonary disease (COPD), bronchiectasis, and cystic fibrosis
• Recent history of abdominal or chest surgery
• Recent history of general anesthesia procedures
• Respiratory muscle weakness due to muscular dystrophy, spinal cord injury, or other neurological diseases
• Medications that can cause shallow breathing
• Pain or injury causing discomfort during coughing or breathing, leading to shallow breathing. Examples include abdominal pain or rib fractures.
• Smoking

Symptoms

Atelectasis may not always present clear symptoms. However, some symptoms may indicate its presence, including:

• Difficulty breathing or shortness of breath
• Rapid and shallow breathing
• Wheezing sound when exhaling
• Coughing

Diagnosis

To diagnose atelectasis, the doctor will first inquire about your medical history to identify possible causes. After that, a physical examination, primarily of the lungs, will be performed to confirm the presence of atelectasis and to look for other lung diseases.

Confirming atelectasis typically involves radiological examinations, with a chest X-ray often being sufficient. However, additional tests may be needed to assess the type and severity, such as:

• CT scan: Provides detailed imaging to assess causes and types.
• Oximetry is the measuring of blood oxygen levels using a small device that attaches to your finger. These oxygen levels correspond to the severity of atelectasis.
• Chest ultrasonography (USG) can help differentiate between atelectasis, hardness, lung enlargement caused by aveolar fluid, and plerural effusion.
• Bronchoscopy is a procedure that involves inserting a small camera into the mouth and then into the deeper airways to determine the origin of the blockage, which could be mucus plugs, tumors, or foreign objects. In addition to looking, this method can eliminate the obstruction.

Management

Therapy depends on the cause and severity of lung collapse. Small-area atelectasis, especially in adults, often resolves without specific treatment. Mucous-thinning medicines are occasionally prescribed to promote mucus discharge. If caused by an obstruction like a tumor, surgery may be necessary. Therapy options include:

• Chest physiotherapy involves deep breathing exercises, particularly after surgery to re-expand a collapsed lung. This method is best learnt before the surgery. Chest physiotherapy techniques include:
• Deep breathing and coughing exercises to eliminate fluid from the airways and increase lung capacity.
• Position the body with the head lower than the chest (postural drainage). This improves mucus drainage from the lower parts of the lungs.
• Patting the chest above the collapsed lung to remove mucus. This procedure can be performed by hand or with a tool like an air-pulse vibrator vest. This instrument vibrates the chest to help release mucus.
• Surgery: removes airway obstructions via suctioning or bronchoscopy. If due to a tumor, surgery may involve tumor removal or reduction, possibly with additional cancer therapies.
• Respiratory therapy: this involves devices like Continuous Positive Airway Pressure (CPAP) for individuals unable to cough or with low oxygen levels post-surgery.

Complications

Complications that may occur due to atelectasis include:

• Decreased blood oxygen levels because oxygen cannot enter collapsed alveoli.
• Increased risk of pneumonia until atelectasis resolves. Mucus buildup, common in atelectasis, contributes to pneumonia.
• Respiratory failure. Collapse in a lung area, especially in infants or those with lung disease, can be life-threatening, leading to respiratory failure.

Prevention

In children, atelectasis often results from airway obstruction. To reduce risk, supervise children to prevent insertion of small objects into their mouth or nose, which can cause obstruction and atelectasis.

In adults, atelectasis is often post-surgery. Discuss with your physician measures to reduce risk, such as respiratory therapy or specific muscle exercises permitted after surgery.

When to See a Doctor?

Seek medical help immediately if you experience discomfort or difficulty breathing. Many conditions can cause breathing difficulty, requiring a doctor's examination for an accurate diagnosis and appropriate therapy. If shortness of breath worsens, promptly visit the emergency department.