Atelectasis
Definition
Atelectasis is an abnormal condition characterized by the collapse of lung tissue, preventing the respiratory exchange of carbon dioxide and oxygen.
Description
Atelectasis - a collapsed or airless state of the lung - may be acute or chronic, and may involve all or part of the lung. The primary cause of atelectasis is obstruction of the bronchus serving the affected area.
Causes
This condition may be caused by obstruction of the major airways and bronchioles, by pressure on the lung from fluid or air in the pleural space, or by pressure from a tumor outside of the lung. In fetal atelectasis the lungs fail to expand normally at birth. This condition may be due to a variety of causes, including prematurity, diminished nervous stimulus to breathing and crying, fetal hypoxia from any cause, including oversedation of the mother during labor and delivery, and obstruction of the bronchus by a mucous plug. In older individuals, atelectasis my be the result of airway obstruction (e.g., by secretions or a tumor) or of failure to deep breathe (postoperatively or because of neuromuscular disease). It occurs most commonly as a complication in the postoperative period, when deep breathing and incentive spirometry are often used to prevent or treat it.
Symptoms
In acute atelectasis in which there is sudden obstruction of the bronchus, there may be dyspnea and cyanosis, elevation of temperature, a drop in blood pressure, or shock. In the chronic form, the patient may experience no symptoms other than gradually developing dyspnea and weakness. X-ray examination may show a shadow in the area of collapse. If an entire lobe is collapsed, the x-ray will show the trachea, heart, and mediastinum deviated toward the collapsed area, with the diaphragm elevated on that side. Bronchoscopy may be included in diagnostic procedures to rule out an obstructing neoplasm or a foreign body if the cause is unknown. Other characteristics include diminished breath sounds, fever, and increasing dyspnea (shortness of breath).
Diagnosis
Atelectasis is diagnosed by clinical exam, close monitoring of a post-operative clinical course, and x-ray.
Treatment
Atelectasis in the newborn is treated by suctioning the trachea to establish an open airway, positive-pressure breathing, and administration of oxygen. High concentrations of oxygen given over a prolonged period tend to promote atelectasis and may lead to the development of retrolental fibroplasia in premature infants. Acute atelectasis is treated by removing the cause whenever possible. To accomplish this, coughing, suctioning, and bronchoscopy may be employed. In atelectasis due to airway obstruction with secretions, chest physiotherapy is often useful. Chronic atelectasis usually requires surgical removal of the affected segment or lobe of the lung. Antibiotics are given to combat the infection that almost always accompanies secondary atelectasis.
Prevention
Deep breathing, aided by the use of inspiration breathing apparatus following surgery, is helpful in preventing complications of atelectasis.
Questions
Is there a collapse of lung tissue? Have you found airway obstruction? What is the probable cause? Is there any problem outside of the lungs that may be a contributing factor? What are the treatment options?
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