If this is not possible other manoeuvres can be tried. A right and left lateral decubitus plate should be exposed. In the decubitus position, the dependant lung should normally deflate. Failure of the lung to deflate on the same side on decubitus film is suspicious of a foreign body. Another method is to assist expiration by compressing the epigastrium with a closed fist, to cause full expiration.
Fluoroscopy can show obstructive emphysema, decreased diaphragmatic movements and mediastinal shift.
This pressure gradient is transmitted to the mediastinum, causing an increase in venous return to the heart, demonstrable as widening on fluoroscopy. This finding, however may be present when inspiring after forced expiration, and may be seen if a breath is taken during an episode of crying. Tuberculosis is especially frequently diagnosed in our country and empirically treated before the correct diagnosis is made. It has been recommended that fluoroscopy be used to try and identify abnormal mediastinal movements before presuming the diagnosis of pneumonia in a child with otherwise unconvincing clinical findings. Most foreign bodies in children are fortunately small and enter the bronchus, and may not cause immediate threat to life.