This lack of surfactant reduces the surface area available for effective gas exchange causing it to collapse if severe. Pressure on the lung from fluid or air can cause atelectasis as well as obstruction of lung air passages by thick mucus resulting from various infections and lung diseases. Tumors and inhaled objects can also cause obstruction of the airway, leading to atelectasis. Anyone undergoing chest or abdominal surgery using general anesthesia is at risk to develop atelectasis, since breathing is often shallow after surgery to avoid pain from the surgical incision. Any significant decrease in airflow to the alveoli contributes to pooling of secretions, which in turn can cause infection.
Chest injuries causing shallow breathing, including fractured ribs, can cause atelectasis.
Common symptoms of atelectasis include shortness of breath and decreased chest wall expansion. If atelectasis only afects a small area of the lung, symptoms are ususally minimal. Fever and increased heart rate may be present if infection accompanies atelectasis. Diagnosis To diagnose atelectasis, a doctor starts by recording the patient's symptoms and performing a thorough physical examination . A chest x ray that shows an airless area in the lung confirms the diagnosis of atelectasis.