Atelectasis Overview and Practice Questions

Atelectasis: Overview and Practice Questions (2024)

by | Updated: Jun 4, 2024

Atelectasis, a common pulmonary condition characterized by the collapse of lung tissue, presents a significant clinical concern in both diagnostic and treatment contexts.

This condition arises when alveoli within the lung become deflated, impacting their essential role in gas exchange.

The clinical implications of atelectasis range from asymptomatic presentations to severe respiratory distress, depending on the extent and rapidity of lung tissue collapse.

Understanding the pathophysiology, diagnosis, and treatment options of atelectasis is essential for reducing its incidence and managing its impacts on patient health.


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What is Atelectasis?

Atelectasis is a medical condition where part or all of a lung collapses, resulting from the deflation of alveoli, the tiny air sacs in the lung. This collapse obstructs normal oxygen exchange and can occur due to blockages, pressure on the lung, or respiratory muscle weakness.

Atelectasis Collapsed Alveoli Vector Illustration


Atelectasis can occur due to various causes, generally categorized into obstruction, compression, or loss of surfactant.

Understanding these underlying factors is crucial for effective diagnosis and treatment:

  • Mucus Plug: Accumulation of mucus in the airways, often seen in patients with asthma, cystic fibrosis, or after surgery due to impaired cough reflex and immobility.
  • Foreign Body: Inhaled objects can block an airway, especially in children.
  • Tumor or Mass: A growth can block the airway, either from within the airway or by pressing on it from outside.
  • Blood Clot: This can occur if there’s bleeding into the lung, such as from a traumatic injury or lung biopsy.
  • Airway Narrowing: Chronic conditions, such as chronic inflammation or scarring, can narrow the airways.
  • Compression: External pressure on the lung, such as from a tumor, enlarged heart, or fluid buildup between the ribs and the lung (pleural effusion).
  • Pleural Effusion: Build-up of fluid in the pleural space (between the lung and chest wall).
  • Pneumothorax: Air in the pleural space, which can push on and collapse the lung.
  • Scar Tissue: Scar tissue can constrict and collapse the lung tissue.
  • Surfactant Deficiency: Surfactant is a substance that helps keep the alveoli open. If there’s not enough surfactant, the alveoli can collapse. This is often seen in premature babies with respiratory distress syndrome.
  • Postoperative Atelectasis: Often seen after surgery, especially abdominal or chest surgeries, due to pain (leading to shallow breathing), anesthesia, or reduced diaphragmatic movement.
  • Prolonged Bed Rest: Being in a reclined position for an extended period can reduce the ability of the lung to fully expand, especially the lower lobes.

Note: Recognizing the specific cause of atelectasis is crucial for its proper management. Different causes require different interventions, and in some cases, such as a foreign body or tumor obstruction, immediate action may be necessary to prevent severe respiratory distress.


Symptoms of atelectasis may include the following:

  • Difficulty breathing (dyspnea)
  • Rapid, shallow breathing
  • Wheezing
  • Coughing
  • Chest pain

Note: Symptoms may vary depending on the extent of lung collapse and the underlying cause. In some cases, especially when the collapsed area is small, atelectasis may not cause noticeable symptoms.

Risk Factors

Several risk factors increase the likelihood of developing atelectasis, spanning various health conditions, medical procedures, and lifestyle choices:

  • Surgery-Related Factors: Use of anesthesia, especially in thoracic and upper abdominal surgeries, and postoperative immobility that impairs lung function.
  • Lung and Airway Conditions: Chronic respiratory diseases like COPD or asthma, diseases causing excessive mucous such as cystic fibrosis, and airway obstructions due to tumors, foreign bodies, or inflammation.
  • General Health and Lifestyle Factors: Smoking, which contributes to lung disease; age, with very young children and older adults at higher risk; obesity affecting lung expansion; and neuromuscular disorders like muscular dystrophy or ALS.
  • Prolonged Bed Rest: Leads to reduced mobility, affecting lung function.
  • Weakness of Respiratory Muscles: Caused by various conditions or the use of muscle relaxants.
  • Impaired Cough Reflex: Resulting from neurological disorders, pain, or certain medications.
  • History of Lung Surgery or Chest Trauma: Can create structural weaknesses in the lung.

Note: Understanding these risk factors aids in the prevention and early detection of atelectasis, particularly in high-risk groups like surgical patients or those with underlying pulmonary conditions.


Atelectasis can lead to several complications, particularly if left untreated or in cases of extensive lung collapse.

These complications can range from minor to severe, affecting overall health and recovery, especially in patients with pre-existing lung conditions or those undergoing major surgeries:

  • Pneumonia: Atelectasis can create an environment conducive to bacterial growth, leading to this infection.
  • Hypoxemia: Reduced oxygenation in the blood due to impaired gas exchange can occur, affecting other organs.
  • Respiratory Failure: In severe cases, atelectasis can contribute to the inability of the lung to perform its gas exchange functions adequately.
  • Bronchiectasis: Prolonged atelectasis can lead to permanent enlargement and damage to the airways.
  • Lung Scarring: Over time, atelectasis can result in fibrosis or scarring of the lung tissue.

Prompt identification and treatment of atelectasis are crucial to prevent these complications, particularly in patients at higher risk, such as those undergoing surgery or with pre-existing lung conditions.

This typically involves interventions to re-expand the affected lung tissue, improve ventilation, and address any underlying causes or contributing factors.

How to Prevent Atelectasis

Preventing atelectasis, particularly in individuals at higher risk due to surgery, underlying lung conditions, or prolonged immobility, involves several proactive strategies:

  • Deep Breathing Exercises: Regularly practicing deep breathing exercises can help expand the lungs and clear airways of mucus.
  • Incentive Spirometry: Using this device encourages deep breathing and is often recommended after surgery to prevent atelectasis.
  • Adequate Pain Control: Effective pain management post-surgery can help patients breathe deeply and cough more effectively, clearing any potential blockages in the airways.
  • Frequent Repositioning: Regularly changing positions, especially for bedridden patients, can help improve lung expansion and prevent fluid buildup.
  • Early Mobilization: Encouraging patients to get up and move as soon as possible after surgery or during long hospital stays can significantly reduce the risk.
  • Avoidance of Smoking: Quitting smoking before any surgical procedure and during recovery helps in maintaining healthy lung function and avoiding mucus buildup.
  • Proper Hydration: Staying well-hydrated helps in keeping the mucus thin and more manageable.
  • Use of Airway Clearance Techniques: Techniques such as chest physiotherapy, postural drainage, or percussion can help in dislodging and clearing secretions from the lungs.
  • Regular Exercise: Maintaining general fitness improves overall lung capacity and strength, aiding in the prevention of atelectasis.
  • Pulmonary Rehabilitation: For those with chronic lung diseases, participating in a structured pulmonary rehabilitation program can be beneficial.

Note: Implementing these measures, especially in high-risk groups, is crucial for preventing atelectasis. In the case of surgery, preoperative planning should include strategies to reduce the risk of postoperative lung complications, including atelectasis.

Atelectasis Practice Questions

1. What is atelectasis characterized by?
Atelectasis is characterized by the partial or complete collapse of a lung or a section of a lung, resulting in reduced or absent gas exchange in the affected area. It typically manifests as diminished breath sounds and reduced oxygenation of blood, and it may show up as an area of increased density on chest x-rays or CT scans.

2. What are the four types of atelectasis?
Resorption, compression, loss of surfactant, and contraction.

3. What are the main causes of atelectasis?
The main causes include airway obstruction (due to mucous plugs, tumors, foreign bodies), compression from outside the lung (like pleural effusion, pneumothorax), loss of surfactant, and decreased respiratory movement (common after surgery or due to muscular weakness).

4. Does atelectasis require treatment?
Atelectasis often requires treatment, especially if it’s causing significant symptoms or if there’s a risk of complications like pneumonia.

5. How do you treat atelectasis?
Treatment often involves addressing the underlying cause, such as removing airway obstructions, along with chest physiotherapy, deep breathing exercises, incentive spirometry, and sometimes bronchoscopy.

6. Which underlying lung diseases cause atelectasis?
Chronic obstructive pulmonary disease (COPD), asthma, and cystic fibrosis are common underlying lung diseases that can lead to atelectasis.

7. What causes resorption atelectasis?
Complete airway obstruction, which causes air not to get to the lungs and is pulled through the pores of Kohn.

8. What are the clinical findings of resorption atelectasis?
Fever, dyspnea, ipsilateral deviation of the trachea, ipsilateral diaphragmatic elevation, absent breath sounds, and fremitus.

9. What is the pathology of compression atelectasis?
Air or fluid accumulation in the pleural cavity that increases pressure and collapses the underlying lung.

10. What can cause compression atelectasis?
Tension pneumothorax and pleural effusion

11. What are the clinical findings of compression atelectasis?
The trachea and mediastinum shift away from the atelectatic lung.

12. What is the cause of contraction atelectasis?
Fibrotic changes in the lung or pleura that prevent full expansion.

13. What is the pathology of contraction atelectasis?
An acute lung injury that can cause pulmonary edema or diffuse alveolar damage.

14. What is lobar atelectasis?
Lobar atelectasis refers to the collapse of an entire lobe of the lung. Since a typical human lung consists of five lobes (three in the right lung and two in the left), this condition implies that one of these distinct sections has completely collapsed, significantly affecting lung function and gas exchange in that particular lobe.

15. What is the best treatment for atelectasis?
The best treatment varies but generally includes addressing the root cause, airway clearance techniques, and ensuring adequate lung expansion and oxygenation.

16. Can atelectasis go away on its own?
Some mild cases, particularly in children, can resolve independently, but medical intervention is often required, especially in adults or severe cases.

17. Is atelectasis considered a serious condition?
It can be serious, particularly if it leads to significant oxygen deprivation, affects a large portion of the lung, or results in complications.

18. What complications can atelectasis lead to?
Potential complications include pneumonia, respiratory failure, bronchiectasis, and lung scarring.

19. When should atelectasis be a concern?
Atelectasis should be a concern if it’s causing symptoms like difficulty breathing, rapid heart rate, significant oxygenation issues, or if it persists without improvement.

20. How long does it typically take for atelectasis to resolve?
The resolution time can vary from days to weeks, depending on the cause, extent of the collapse, and the treatment’s effectiveness.

21. Can atelectasis become a permanent condition?
If not properly treated, or in the case of repeated or chronic atelectasis, it can lead to permanent lung damage or scarring.

22. In the case of atelectasis, which side should be positioned upwards?
The “good lung up” position, where the unaffected lung is positioned above the collapsed one, is often recommended to improve ventilation and oxygenation.

23. Does atelectasis cause respiratory acidosis?
Atelectasis itself doesn’t directly cause respiratory acidosis, but if it leads to significant hypoventilation and retention of CO2, then respiratory acidosis can occur.

24. Is it possible to have atelectasis for years?
Chronic atelectasis can persist for extended periods, including years, especially if underlying causes are not effectively addressed.

25. Do all pneumothoraces result in atelectasis?
Not all pneumothoraces result in atelectasis, but a pneumothorax can lead to or coexist with atelectasis.

26. How painful is atelectasis?
Atelectasis is usually not painful, but the condition causing it, such as surgery or infection, can be.

27. How is atelectasis defined?
Atelectasis is defined as the collapse or closure of a lung resulting in reduced or absent gas exchange.

28. How does atelectasis lead to pleural effusion?
Atelectasis itself doesn’t typically lead to pleural effusion; however, conditions like infections or inflammation that cause atelectasis can also lead to pleural effusion.

29. Does atelectasis cause crackling sounds?
Atelectasis can cause crackling (rales) or diminished breath sounds upon auscultation, especially near the affected area.

30. Is atelectasis an obstructive or restrictive condition?
Atelectasis is generally considered a restrictive lung condition, as it limits the expansion of the lung.

31. What does the term atelectasis mean?
The term “atelectasis” originates from Greek, meaning incomplete expansion, typically referring to partially or wholly collapsed lung tissue.

32. How is atelectasis diagnosed?
Atelectasis is typically diagnosed using imaging studies like chest x-rays or CT scans, often supplemented with physical examination and oxygen saturation measurements.

33. How long does atelectasis typically last?
The duration of atelectasis varies depending on the cause and severity but typically resolves with treatment within days to a few weeks.

34. Which conditions can improve atelectasis using CPAP or BiPAP?
Continuous positive airway pressure (COPD) or bilevel positive airway pressure (BiPAP) can be effective in treating atelectasis by maintaining positive airway pressure and improving lung expansion, especially in cases related to sleep apnea, muscular weakness, or obesity hypoventilation syndrome.

35. Can the severity of atelectasis worsen over time?
If left untreated, or if the underlying cause persists, the severity of atelectasis can worsen, leading to complications.

36. What are the common causes of atelectasis?
Common causes include airway obstruction, chest or abdominal surgery, sedentary lifestyle, muscle weakness, lung diseases, and mechanical ventilation.

37. Why does atelectasis occur after surgery?
Postoperative atelectasis often occurs due to reduced deep breathing and coughing, pain, prolonged lying in bed, and the effects of anesthesia.

38. What is the most common cause of atelectasis?
Blockage of the airways (obstruction), either from internal factors like mucus plugs or external compression, is the most common cause.

39. Are there types of atelectasis that are not reversible?
Most types of atelectasis are reversible with treatment; however, repeated or long-standing atelectasis can lead to lung scarring or damage that may not be fully reversible.

40. Which healthcare professionals treat atelectasis?
Atelectasis is treated by various healthcare professionals, including pulmonologists, respiratory therapists, primary care physicians, and surgeons.

41. What triggers the occurrence of atelectasis?
Atelectasis is triggered by airway obstruction (due to mucus, tumor, or foreign bodies), compression of the lung (by fluid, tumor, or abdominal distention), anesthesia, sedentary lifestyle, or thoracic surgery.

42. Are air bronchograms a feature of atelectasis?
Air bronchograms are not typically a feature of atelectasis; they are more commonly associated with lung consolidation, like in pneumonia.

43. What are the mechanisms behind the occurrence of atelectasis?
The mechanisms include obstruction of airways, compression of lung tissue, decreased surfactant (helps keep airways open), and lack of respiratory movement or muscle weakness.

44. What are the symptoms of atelectasis?
Symptoms can include difficulty breathing, rapid shallow breathing, coughing, and a reduced ability to exercise.

45. Which groups are most affected by atelectasis?
Individuals undergoing major surgery, especially abdominal or chest surgery, those on prolonged bed rest, and people with underlying lung diseases are most affected.

46. Why does atelectasis occur after a splenectomy?
After a splenectomy, especially if the procedure is open and not laparoscopic, pain and restricted diaphragmatic movement can reduce lung expansion, leading to atelectasis.

47. Can atelectasis lead to pneumonia?
Yes, atelectasis can lead to pneumonia, especially when lung collapse leads to mucus accumulation, creating an environment for bacterial growth.

48. Can atelectasis lead to tracheal deviation?
Large-scale atelectasis can lead to tracheal deviation, especially if the collapse is significant enough to alter the pressure and volume within the chest cavity.

49. Are bronchiectasis and atelectasis the same condition?
No, they are not the same. Bronchiectasis is a chronic condition involving the permanent enlargement of parts of the airways, while atelectasis is the collapse of a part or all of a lung.

50. Who is at risk for developing atelectasis?
Those at risk include surgical patients (particularly after chest or abdominal surgeries), bedridden individuals, people with muscle weakness or lung diseases, and smokers.

51. When can atelectasis become dangerous?
Atelectasis can become dangerous if it leads to severe oxygenation problems, large portions of the lung are affected, or if it results in complications like pneumonia or respiratory failure.

52. When should atelectasis be coded in medical records?
Atelectasis should be coded in medical records when diagnosed by a healthcare professional, typically after clinical assessment and confirmation by imaging studies.

53. Are pneumothorax and atelectasis the same condition?
No, pneumothorax (air in the pleural space causing lung collapse) and atelectasis (collapse of lung tissue) are different conditions, though they can sometimes coexist.

54. Does atelectasis indicate lung cancer?
Atelectasis itself does not indicate lung cancer, but it can be a secondary sign if a tumor is blocking an airway.

55. Why does atelectasis appear white on an x-ray?
Atelectasis appears white on an x-ray because the collapsed area lacks air; x-rays show denser tissue, like collapsed lung areas, as whiter than air-filled areas.

56. Can atelectasis be cured?
Many cases of atelectasis can be cured or resolved, particularly if treatment targets the underlying cause effectively.

57. Which type of atelectasis is most commonly seen?
Obstructive atelectasis, where an airway blockage prevents air from reaching the lungs, is the most common type.

58. What airway obstruction signs are associated with atelectasis?
Signs include diminished breath sounds on the affected side, wheezing, and difficulty breathing.

59. When does absorption atelectasis occur?
Absorption atelectasis occurs when air in the alveoli is absorbed into the bloodstream faster than it can be replenished, often happening with high oxygen concentration therapy.

60. Can atelectasis occur from not taking deep breaths?
Yes, not taking deep breaths can lead to atelectasis, as shallow breathing fails to fully inflate the alveoli, potentially causing them to collapse.

61. What does atelectasis look like on a chest X-ray?
On a chest x-ray, atelectasis may appear as areas of increased density or whiteness and can sometimes lead to displacement of structures like the trachea.

62. Are lung consolidation and atelectasis identical?
No, they’re not identical. Lung consolidation refers to the filling of the alveoli with fluid or other material, while atelectasis is the collapse of lung tissue.

63. Can atelectasis cause fever following surgery?
Yes, atelectasis can sometimes cause a mild fever following surgery, likely due to inflammatory responses in the collapsed lung tissue.

64. Is atelectasis a type of pneumonia?
No, atelectasis is not a type of pneumonia. However, it can lead to pneumonia, particularly if lung collapse allows for bacterial growth.

65. How does atelectasis lead to fever?
The fever in atelectasis is possibly due to inflammatory cytokines released in response to the collapsed lung tissue, though the exact mechanism is unclear.

66. Is atelectasis categorized as a restrictive lung disease?
Atelectasis is often considered a restrictive lung condition since it limits the lung’s ability to expand fully.

67. What should be known when a patient has atelectasis?
When a patient has atelectasis, it’s important to understand the underlying cause, monitor for any breathing difficulties, and engage in appropriate treatments like chest physiotherapy or addressing airway blockages.

68. Can atelectasis result in chest pain?
While not as common, atelectasis can sometimes cause chest pain, especially if it leads to significant lung collapse or is accompanied by other complications like pleural effusion.

69. Where is atelectasis most commonly located in the lungs?
Atelectasis is most commonly located in the lower lobes of the lungs due to gravity and the effects of anesthesia or abdominal pressure.

70. What does atelectasis feel like?
Atelectasis may feel like shortness of breath, rapid shallow breathing, and sometimes chest pain or discomfort. However, small areas of atelectasis might not produce noticeable symptoms.

71. Where is bibasilar atelectasis located?
Bibasilar atelectasis is located at the bases of both the left and right lung lobes.

72. Is it possible to live with atelectasis?
Yes, it is possible to live with atelectasis, especially if it’s minor and properly managed. However, the impact on life depends on the extent of the atelectasis and underlying health conditions.

73. Where does subsegmental atelectasis occur?
Subsegmental atelectasis occurs in smaller peripheral divisions of the lung lobes, specifically within the subsegments of the bronchial tree.

74. Is atelectasis equivalent to a collapsed lung?
Atelectasis is a form of lung collapse limited to certain areas within the lung rather than a complete lung collapse, which is typically referred to as pneumothorax.

75. Does atelectasis typically cause coughing?
Atelectasis doesn’t typically cause coughing unless it’s accompanied by other respiratory conditions like infections or significant mucus blockage.

76. Who was the first to discover atelectasis?
Atelectasis was first described by Laennec in the early 19th century through his work with the stethoscope and pioneering studies in chest diseases.

77. Which factors cause atelectasis?
Factors causing atelectasis include airway obstruction, lung compression (e.g., from a tumor or pleural effusion), anesthesia, sedentary lifestyle, chest surgeries, and muscle weakness.

78. Where in the lung is atelectasis typically located?
Atelectasis is typically located in the lower lobes of the lung, often due to the effects of gravity, anesthesia, or abdominal pressure.

79. Can atelectasis lead to a pneumothorax?
While atelectasis itself doesn’t typically lead to pneumothorax, certain interventions to treat atelectasis, like high-pressure mechanical ventilation, can potentially cause a pneumothorax.

80. Why does atelectasis cause dullness when percussed?
Atelectasis causes dullness when percussed because the normally air-filled lung spaces become solid from the collapse, and solid areas transmit sound differently, resulting in a dull sound.

Final Thoughts

Atelectasis is a condition that demands attention due to its propensity to disrupt pulmonary function and its role as a precursor to more severe respiratory complications.

Its management is multi-pronged, often addressing the underlying cause, promoting lung expansion, and enhancing overall respiratory health.

The prevention and effective treatment of atelectasis, particularly in high-risk groups such as surgical patients and those with chronic lung diseases, are crucial for minimizing its impacts and improving patient outcomes.

As our understanding of pulmonary health evolves, so too will our strategies for managing and preventing conditions like atelectasis, underscoring the importance of ongoing research and clinical vigilance in this field.

John Landry, BS, RRT

Written by:

John Landry, BS, RRT

John Landry is a registered respiratory therapist from Memphis, TN, and has a bachelor's degree in kinesiology. He enjoys using evidence-based research to help others breathe easier and live a healthier life.


  • Faarc, Kacmarek Robert PhD Rrt, et al. Egan’s Fundamentals of Respiratory Care. 12th ed., Mosby, 2020.
  • Grott K, Chauhan S, Dunlap JD. Atelectasis. [Updated 2023 Jun 19]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2023.

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