Discussion
In the pediatric population, intubation-related tracheal tear due to a large endotracheal size is the most common mechanism of airway injury, so selection of appropriate tube size is essential (3,4). Furthermore, frequent manipulation of the tube without overinflation or deflation and intubation performed by inexperienced clinicians are common causes of tracheal tears (5).
Tracheostomy-related posterior tracheal tears occur infrequently and are less commonly than intubation-related tracheal tear. They usually occur during tracheostomy placement, use of cuffed tubes, and overinflation of the cuff or tear following tracheal trauma during introducer insertion (6,7,8). Tracheostomy-related tears are is mainly located proximal to the carina and distal to the insertion point of the tracheostomy.(3,9) Pediatric patients are at higher risk of iatrogenic tracheal tears than adults due to anatomical differences: weaker intercartilaginous membrane, higher cartilage elasticity, and smaller airway lumen. In addition, the mortality rate in pediatric patients after iatrogenic tracheal tears is as high as 75%, so the selection of the appropriate tube size is essential (3). Short thick neck, kyphoscoliosis, and emergency cases with difficult intubation increase the risk of tracheal tears in pediatric patients (1,7,9).
Iatrogenic trachel lacerations may present immediately as impaired ventilation or later in the postoperative period with the complications of compressive pneumothorax, pneumomediastinum, or extensive subcutaneous emphysema, especially during retching or coughing or in mechanically ventilated patients (1,10). Furthermore, tracheobronchial tears can lead to many other complications such as respiratory distress, mediastinitis, tracheal stenosis, recurrent nerve injury, fistula, and abscess. The gold standard for diagnosis is flexible or rigid tracheobronchoscopy, which helps determine the site, extension, and location of the tear with respect to the carina. Imaging studies such as computed tomography (CT) can help identify complications such as pneumothorax, pneumonia, pneumomediastinum, and mediastinitis. Chest and lateral neck radiographs are helpful too, but they have a false negative rate reaching 10% (1,2,5,9,10). In addition, esophagoscopy is essential to rule out esophageal injuries (3,10). In 88% of cases, tears are diagnosed intraoperatively because of emphysema in the mediastinum or impaired ventilation (11).
Treatment can be conservative or surgical. Conservative treatment is indicated for mechanically ventilated patients and hemodynamically stable patients with uncomplicated and small (<3 cm) tears, no protrusion of mediastinal structures into the tracheal lumen, and only mild emphysema. Conservative treatment includes the insertion of longer/adjustable-length tracheostomy tubes or endotracheal tube, preferably under endoscopic guidance with an appropriate tube size, which is placed distal to the tear site with continuous cuff pressure measurement. If the tear is close to the carina, positioning the cuff distal to the tracheal tear is challenging, so tube placement should be performed under endoscopic guidance to ensure proper tube placement, along with continuous cuff pressure measurement to avoid tear enlargement (1,5,10,12-14). Furthermore, the approach to mechanical ventilation is important as positive pressure ventilation can exacerbate the injury. On the other hand, ventilation helps the tear to spontaneously collapse, thus supporting tear healing. All this should be done under the cover of a broad-spectrum antibiotic to reduce the risk of infection (1,3,10). Surgical treatment is preferred for patients with large or complicated tears, tracheal avulsion, and extensive emphysema and those who are unstable during ventilation. Surgical repair should be performed as soon as possible to decrease the risk of complications. The choice of surgical approach should be guided by the anatomical site of the tear. Using the tracheostomy opening is highly recommended because the incision already exists and the laceration is almost always proximal to the carina and rarely extends beyond it (1). Deganello et al. described surgical repair of a large proximal tracheal tear that ended above the carina in an adult patient through an extended tracheotomy opening technique with interrupted sutures using a thoracoscopic needle holder (1). Welter et al. described a repair of similar tear with no surgical access using an optical needle holder with interrupted sutures through rigid bronchoscopy (13). Chaaban et al. treated a large tear in a surgically unfit tracheostomized adult patient using a customized silicone stent, which was inserted under bronchoscopy guidance to bridge the tear end. Then, at the level of the tracheostomy site, an anterior window was made in the stent to insert the tracheostomy tube through the stent (14). If the tear extends up to the bronchial tree, thoracotomy is required. Tears involving the carina, right bronchial tree, and proximal region of the left main bronchus necessitate right thoracotomy. Left thoracotomy is required if the injuries lie in the left main bronchus near the lung hilum and left bronchial tree (5). If significant tracheal mucosa injury and concern of stenosis are present, tracheal segment resection with end-to-end anastomosis may be performed. In addition, sealing the tear at the anterior esophageal wall can help secure the tear. After the repair of the tear, a soft noncuffed tube should be used. If a cuffed tube is used, the cuff pressure need to be monitored. To decrease peristaltic movement, nasogastric tube should be inserted for at least 1 week. For both surgical and nonsurgical treatment, multiple follow-up chest and lateral neck radiography is needed, as well as regular serial endoscopic examinations, such as daily bedside fiberoptic endoscopy and bronchoscopy for a few days. During assessment, the endotracheal or tracheostomy tube should be carefully retracted to check for healing, proper tube placement at a suitable level, and evidence of stenosis or tracheoesophageal fistula (1,9,11).