What is the most common cause of atelectasis in patients?

Airway obstruction is the most common cause of atelectasis in patients. Atelectasis refers to the collapse or incomplete expansion of the lung or a section of the lung, leading to reduced gas exchange and impaired ventilation. When the airway becomes obstructed, air cannot reach the alveoli in that section of the lung, which can cause the alveoli to collapse over time due to a lack of pressure. This can occur in various situations, such as following surgery when patients might not take deep breaths or cough effectively due to pain, neuromuscular weakness, or sedation.

While other conditions like pneumonia, heart failure, and lung cancer can lead to atelectasis, they are not as direct as airway obstruction. Pneumonia can cause inflammation and consolidation in the lung but is often a consequence rather than a primary cause. Heart failure can lead to fluid accumulation in the lungs, making it difficult for gases to exchange, and lung cancer can create physical masses that obstruct airways, but they are less common causes in the general population and are often secondary complications. Therefore, airway obstruction stands out as a primary driver of this condition.