Atelectasis

OVERVIEW

Atelectasis is a common lung condition that involves a total or partial collapse of the lungs due to the deflation of the alveoli. The presence of fluid in the alveoli could also lead to Atelectasis. Atelectasis usually occurs on one side (unilaterally), affecting the entire lobe of the lung or part of it.

The alveoli are tiny sacs within the lungs where gaseous exchange takes place. They are elastic structures that expand when filled with air. In Atelectasis, these tiny sacs become deflated, causing the lungs to collapse. The collapsed lung will not be able to oxygenate the whole body, causing the body not to function well.

There is a form of Atelectasis called: Atelectasis bibasilar. Atelectasis bibasilar involves the collapse of the two lungs’ lower parts (bases). It is a life-threatening condition and should be treated immediately.

Atelectasis and consolidation of the lungs are conditions that affect the alveoli. In Atelectasis, the alveoli are deflated, whereas, in the consolidation of the lungs, the alveoli are filled with air or fluid.

Atelectasis is less severe in adults. It is more potent in infants and little children and could be life-threatening. Adults who have other lung diseases, in addition to Atelectasis, are treated as emergency cases.

Types of Atelectasis

Atelectasis is of two broad types namely; obstructive and non-obstructive Atelectasis.

Obstructive Atelectasis

It is also called resorptive Atelectasis. In this type of Atelectasis, the airway is blocked by a substance or object. Mucus plugs or foreign bodies are things that can physically block the airways. 

The mediastinum (trachea) shifts to the side of the affected lung rather than the central position observed in the individuals. 

Non-obstructive Atelectasis

There is no physical blockage of the airway in non-obstructive Atelectasis. It is due to other reasons like fluid accumulation and fibrotic changes.

Types of non-obstructive Atelectasis include:

• Relaxation or compressive 
• Cicatricial
• Adhesive
• Rounded

KEY FACTS

• In Atelectasis, the lungs collapse because the alveoli are deflated. 
• Infants’ lack of surfactant (the substance that helps the lungs stay inflated) can also cause the lungs to collapse, leading to infant respiratory distress syndrome.
• Several factors cause Atelectasis. Atelectasis occurring after the surgery is a common respiratory complication. Lung tumours, fibrosis, foreign objects in the airways and injuries to the chest can all lead to Atelectasis.
• Complications of Atelectasis include pneumonia, low oxygen supply to the blood (hypoxemia) and respiratory failure.

Atelectasis Pathophysiology

Having a good grasp of Atelectasis pathophysiology will help in understanding the disease condition.

When there is airway obstruction, either due to blockage or pressure from outside the airway, there is reduced ventilation, and as a result, air cannot enter or leave the affected alveoli. This air becomes trapped.

The trapped air enters the bloodstream leaving the affected alveoli without air. The airless alveoli collapse. In Atelectasis pathophysiology, the lung’s affected part folds inwards toward the pleura.

SYMPTOMS 

Difficulty in breathing (dyspnea) is a significant symptom of Atelectasis. Atelectasis symptoms are not usually specific to the disease. The symptoms are typically present in other respiratory conditions. Hence one needs to see the doctor immediately after the onset of symptoms. Atelectasis symptoms may sometimes not be apparent, particularly when a small part of the lung is affected.

Observable symptoms include

• Dyspnea (difficulty in breathing)
• Chest pain, usually on the affected side
• Cough
• Bluish discolouration of the skin and lips
• Increased breathing

DIAGNOSIS

The doctor conducts diagnostic tests to help establish or rule out his suspicion of Atelectasis. Some of these tests include:

• Chest X-ray 
• Computed Tomography (C.T.) scan
• Bronchoscopy 
• Ultrasound scan (occasionally) 

CAUSES

Surgery is the primary cause of Atelectasis. The use of general anaesthesia before surgery can cause the lungs to collapse. About 90% of people that undergo general anaesthesia before surgery develop Atelectasis. Causes of Atelectasis include

Surgery: General anaesthesia is a leading cause of Atelectasis post-surgery. The use of general anaesthesia, even in the absence of surgical complications, causes about 15-20% of the lung base to collapse.

Using muscle relaxants during surgery can also lead to lung collapse. Obese people and pregnant women are at higher risk of developing Atelectasis during surgery. Inadequate pain control during surgery can inhibit coughing, putting the person at risk of Atelectasis.

Surgeries involving the cardiothoracic region puts one at risk of getting Atelectasis.

Airways obstruction: Anything that blocks the airways will make breathing difficult, possibly leading to Atelectasis. It could be mucus, an inhaled object, or even a tumour inside the respiratory tract. These lead to a type of Atelectasis called obstructive Atelectasis.

Pressure on the airways: Structures outside the airways can compress the airway leading to lung collapse. Examples of things that put pressure on the airway from outside include:

• Tumours outside the airways can cause a deflated lung.
• Pneumothorax (air in the thoracic cavity)
• Pleural effusion (presence of fluid in the thoracic cavity)
• Pneumonia
• Abnormal bone in the chest
• Scarred lung tissue

RISK FACTORS

Things that put people at risk of getting Atelectasis are:

• Smoking
• Old age
• Obesity
• Long-standing lung disease
• Any condition that causes dysphagia (difficulty swallowing)
• Long periods of bed rest

PREVENTION

To prevent Atelectasis, we can take the following measures:

• Infants and children shouldn’t be allowed to play with sharp objects to prevent them from blocking the airways, causing obstructive Atelectasis.
• The use of general anaesthesia should be limited, if possible, especially in patients with a high risk of Atelectasis.
• Proper pain control during surgery
• Doctors should take patients through breathing exercises after surgery. 
• Abstain from smoking

TYPICAL TREATMENTS

Most cases of Atelectasis resolve independently, while other instances require intervention. Some of these interventions include:

• Removal of anything compressing the airway, like tumours.
• Bronchoscopy, to remove mucus or whatever is blocking the airway.
• Physiotherapists use chest and breathing exercises to improve patients breathing after surgery.
• A breathing tube for Aida patient’s breathing after surgery.

CONCLUSION

Atelectasis causes the body not to receive enough oxygen because the alveoli become deflated, and the lungs collapse. It is usually more severe in infants and children than in adults. 

Adequate treatment will efficiently resolve Atelectasis. In persistent cases, the doctor will take more intense methods to get rid of the lung collapse.