[140] Dense and metallic objects will usually be readily seen in the roentgenograms and fluoroscope, but many foreign bodies are of a nature which will produce no shadow; the roentgenologist should, therefore, be prepared to interpret the pulmonary pathology, and should not dismiss the case as negative for foreign body because one is not seen. Even metallic objects are in rare cases exceedingly difficult to demonstrate.
[FIG. 75.—Radiograph showing pathology resulting from complete obstruction of a bronchus with atelectasis and drowned lung resulting. Foot of an alarm clock in left bronchus of 4 year old child. Present 25 days. Plate made by Johnston and Grier.]
Positive Films of the Tracheo-bronchial Tree as an Aid to Localization.—In order to localize the bronchus invaded by a small foreign body the positive film is laid over the negative of the patient showing the foreign body. The shadow of the foreign body will then show through the overlying positive film. These positive films are made in twelve sizes, and the size selected should be that corresponding to the size of the patient as shown by the roentgenograph. The dome of the diaphragm and the dome of the pleura are taken as visceral landmarks for placing the positive films which have lines indicating these levels. If the shadow of the foreign body be faint it may be strengthened by an ink mark on the uncoated side of the plate.
[FIG. 76.—Partial bronchial obstruction for long period of time Pathology, bronchiectasis and pulmonary abscess, produced by the presence for 4 years of a nail in the left lung of a boy of 10 years]
Bronchial mapping is readily accomplished by the author's method of endobronchial insufflation of a roentgenopaque inert powder such as bismuth subnitrate or subcarbonate (Fig. 77). The roentgenopaque substance may be injected in a fluid mixture if preferred, but the walls are better outlined with the powder (Fig. 77).
[FIG. 77.—Roentgenogram showing the author's method of bronchial mapping or lung-mapping by the bronchoscopic introduction of opaque substances (in this instance powdered bismuth subnitrate) into the lung of the patient. Plate made by David R. Bowen. (Illustration, strengthened for reproduction, is from author's article in American Journal of Roentgenology, Oct., 1918.)]
ERRORS TO AVOID IN SUSPECTED FOREIGN BODY CASES
1. Do not reach for the foreign body with the fingers, lest the foreign body be thereby pushed into the larynx, or the larynx be thus traumatized. 2. Do not hold up the patient by the heels, lest a tracheally lodged foreign body be dislodged and asphyxiate the patient by becoming jammed in the glottis. [143] 3. Do not fail to have a roentgenogram made, if possible, whether the foreign body in question is of a kind dense to the ray or not. 4. Do not fail to search endoscopically for a foreign body in all cases of doubt. 5. Do not pass blindly an esophageal bougie, probang, or other instrument. 6. Do not tell the patient he has no foreign body until after roentgenray examination, physical examination, indirect examination, and endoscopy have all proven negative.