Clinical findings of airway rupture are sometimes unclear and may be hidden by other traumatic injuries. Alternatively, some obvious airway rupture features may be wrongly assigned to lesions of other structures, especially oesophagus.

Pain associated with swallowing and skin contusion, neck emphysema, pneumo-mediastinum and hoarseness are clinical findings that can allow suspecting the diagnosis.

Other symptoms are dyspnoea, cough, bloody saliva, haemoptysis and dysphagia. These symptoms are frequently associated with physical features as cyanosis, pneumothorax, vocal cord paralysis, aphonia and subcutaneous emphysema diffused also into shoulders and chest fat planes (Fig. 7.8).

The pneumothorax is frequently large and under tension (Fig. 7.9). The air leak may be persistent after introduction of pleural drainage. In these circumstances, the lung fails to expand. One unusual but characteristic feature that may be evidenced in cases of bronchial tear and a large pneumothorax is that bronchial rupture may allow the lung to bulge downwards from the hilum giving rise the “fallen lung” sign (Fig. 7.10). Normally, in the presence of a pneumothorax, the lung recoils towards the hilum, the vascular pedicle persists in its normal site and the lung remains perfused although under-ventilated.

If the “fallen lung sign” is present, the consequent ventilation-perfusion discrepancy may result in hypoxia and cyanosis.

It is also necessary to evaluate if tracheal injury is partial or complete.

Clinical signs of partial tracheal rupture include gradually increasing dyspnoea, haemoptysis, hoarseness and subcutaneous emphysema. In complete tracheal rupture, the skin of the anterior neck moves in and out with breathing movement and a gap in the tracheal rings can be felt beneath the moving skin.

Tracheo-bronchial injuries could also be suspected in the presence of subcutaneous cervical emphysema expanding with mechanical ventilation, pneumo-mediastinum and recurrent pneumothorax due to the persisting air leak (Fig. 7.11) [17].

Sometimes, patients have other blunt lesions as laryngeal trauma, cervical spine or mandibular fractures, oesophageal injury, clavicular, scapular or ribs fractures. Oesophageal perforation is present in up to 20% of cases (Fig. 7.12).

Clinical features of tracheal stenosis (Fig. 7.13), as a consequence of a tracheal injury, include dyspnoea on effort, stridor or wheezing and episodes of obstruction even with small amounts of mucus. Other complications could be the development of a tracheo-oesophageal fistula (Fig. 7.14) or a tracheo-innominate fistula.

The most common clinical manifestation of a post-traumatic tracheo-oesophageal fistula is represented by considerable secretion associated with cough and recurrent broncho-pneumonia. Gastric lumen enlargement may also occur.

Tracheo-innominate fistula may be associated with severe haemoptysis.

CT is considered the more relevant diagnostic tool in patients with blunt chest trauma following the basic and indispensable chest X-ray film [18].

When a closed injury to the airways is suspected, it is important to perform immediate neck and chest CT scan, including three-dimensional image reconstruction of the trachea and the main bronchus.

Traditionally, the gold standard for the diagnosis is bronchoscopy because it enables visualization both the side and extent of the tracheo-bronchial injury. But in patients with severe respiratory insufficiency or in haemodinamically unstable patients, it may be impossible to perform. Bronchoscopy is not only time consuming, but also not always immediately available. Differently from bronchoscopy, CT is non-invasive, quicker and more ready available [5].

CT can clearly demonstrate fascial fat planes, arterial and venous vessels, larynx, trachea, bronchus and oesophagus traumatic lesions (Figs. 7.12 and 7.14), and it is the most important preoperative diagnostic imaging modality for determining the location, extent and type of airway lesions [6, 19].

The MDCT protocol that is illustrated is designed for 64-row CT scanner; images are acquired at 0.625 collimation, with reconstruction axial slice of 2.5 mm, pitch of 0.984 and gantry rotation time of 0.5 s.

Preliminary unenhanced neck and chest CT is obtained to detect free air bubbles into the superficial and deep fascial fat planes or in fluid collections to depict blood clots inside haemothorax, haemopericardium and haemomediastinum.

Intravenous administration of contrast medium is mandatory for clearly evidencing neck and chest injuries.

Intravenous injection of a volume of 70–90 of iodine c.m. is generally sufficient for evaluating the enhancement of vessel lumen and surrounding other structures.

The contrast medium (c.m.) is injected with an 18–20 gauge needle through the ante-cubital vein by the use of a dual syringe power injector.

The c.m. transit time is determined by using a test-bolus in the ascending aorta lumen.

The optimal delay time corresponds to the peak arrival time of a test-bolus in the aortic lumen. The image acquisition is triggered at an attenuation threshold of 150 UH.

For better viewing, the enhancement alterations of the neck and chest tissues and vessels, contrast agents with higher concentration of iodine (400 mg/mL) and high injection rates (at least 3–4 mL/s) are preferred and are followed by a 30–50 mL saline chaser, also injected at a rate of 3–4 mL/s.

The c.m. arterial phase is mandatory to detect neck and chest arterial injuries.

The portal phase acquisition, obtained with a scan delay of 70 s, gives maximum airway wall, neck and mediastinum tissues and venous lumen enhancement.

In selected cases, orally administration of iodine contrast material could be helpful for demonstrating tracheo-oesophageal fistulization.

Sagittal and coronal MIP reformatted images are useful for localizing the ruptured segment of tracheo-bronchial tree and evaluating the map of the distribution of air bubbles, pneumothorax and blood collections. The post-processing procedure mainly requires a minimum-intensity projection technique for airway imaging. If tracheo-bronchial injury is suspected, three-dimensional (3D) extraction of the airway may be useful by focusing the 3D volume-rendering technique on the tracheo-bronchial tree. This technique is classically utilized for depicting stenosis or distortion of the tracheo-bronchial lumen, but may also allow the diagnosis of tracheo-bronchial injury by demonstrating a wall defect and/or an abnormal position of lobar and segmental bronchi [20].

As the clinical symptoms of acute airway injuries may not be specific and initially hidden by the presence of traumatic lesions of other organs and structures; the chest radiograph and CT scan are both important methods for diagnostic evaluation.

There are two main radiographic manifestations of tracheal and bronchial injuries: evidence of air leakage at the site of rupture and dysfunctional ventilation of the lung distal to the rupture. Evidence of air leakage is the more critical finding, and the absence of air leakage makes the diagnosis of a tear of the tracheo-bronchial tree very difficult (Fig. 7.15) [9].