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CLIPP 12: 10-month old with a cough

Terms in this set (63)

PA and lateral chest films are a good choice as part of your initial workup, because you know she has asymmetric breath sounds and you want to see whether there are radiographic findings to account for the asymmetry.
Bilateral decubitus or inspiratory/expiratory chest films are used to evaluate whether obstruction of the larger airways, such as that due to a foreign body, is present.
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Decubitus chest films are performed with the child lying on her side. The concept of the lateral decubitus film is that the dependent lung should deflate slightly compared to the non- dependent lung due to the effect of gravity. If each lung deflates slightly when dependent as expected, there is less likelihood of an obstruction in a large airway. If one side does not deflate as expected, this suggests an obstruction in a large airway.
The rationale for inspiratory/expiratory films is similar to that for decubitus films. The airway containing an obstruction does not allow the distal lung to deflate fully and results in asymmetric deflation with expiration. The advantage of decubitus films over inspiratory/expiratory films is that decubitus films do not require the patient to be able to hold a breath in inspiration or expiration. The disadvantage is that the abnormal finding, if present, is more subtle than on inspiratory/expiratory films.

These are the findings you would expect with an aspiration obstructing the right airway:
PA film (with the child in a sitting position): Right hemidiaphragm is flattened, suggesting unilateral hyperexpansion on the right.
Right decubitus: With child on her right side, the mediastinal structures remain in the midline, rather than shifting towards the right lung due to gravity, further demonstrating the fixed hyperinflation of the right lung.
Left decubitus: With child on her left side, the mediastinal structures shift towards the left lung as expected.
Hyperinflation is seen in those foreign body aspirations that result in a "ball valve" effect, in which the aspirated object creates a partial obstruction to airflow during inspiration but fully obstructs the airway during exhalation. The result is air trapping with each breath.
Alternatively, when an aspirated object causes a complete airway obstruction, the result is a total lack of airflow to the bronchus, which can lead to atelectasis and signs of volume loss on x-ray (e.g., mediastinal shift towards the affected side or elevation of the hemidiaphragm on the affected side).