Traumatic Tracheobronchial Injury

Introduction

Tracheobronchial injuries, though rare, manifest in approximately two to three percent of individuals experiencing neck or chest trauma. Swift diagnosis and management are imperative due to their life-threatening nature. These injuries typically stem from accidents or forceful impacts to the chest. Identification often relies on X-ray imaging. Initial measures involve stabilizing the airway, pinpointing the injury's location and severity, and closely monitoring progress to gauge the effectiveness of interventions.

What Is A Traumatic Tracheobronchial Injury?

Tracheobronchial injuries encompass the respiratory system components, including the trachea, larynx, primary carina responsible for dividing the left and right bronchi, and the subsequent main bronchi that further branch into smaller airways. Ordinarily shielded by the ribcage, sternum, and spine, trauma to these structures can precipitate life-threatening consequences. Such injuries typically manifest either in the neck region (cervical), involving the larynx, cervical trachea, and vocal cords, or within the chest (thoracic), affecting the carina, thoracic trachea, and mainstem bronchi.

Traumatic injuries to the tracheobronchial system can arise from various sources:

• Iatrogenic Causes: These encompass mishaps occurring during medical procedures, such as inadvertent injuries while inserting breathing tubes, performing esophageal surgeries, conducting bronchoscopies (a procedure used to visualize the inside of the airways and lungs with the help of a thin, flexible tube called a bronchoscope), or executing tracheostomies (a surgical procedure in which a small opening is created in the front of the neck and into the trachea) involving the creation of an external opening in the trachea. Although infrequent, the incidence of injuries attributable to these procedures is exceedingly low, approximately up to one percent.

• Blunt Trauma: These result from accidents or falls involving high-impact collisions or direct blows. These occurrences are rare, affecting approximately 0.5 to 2 percent of cases. Chest injuries stemming from blunt trauma may include crush injuries, heightened airway pressure leading to airway rupture, or deceleration injuries where abrupt cessation of movement places stress on the tracheobronchial tree. Neck injuries may arise from forceful blows to the anterior neck, hyperextension of the neck as seen in high-riding seatbelt injuries, or incidents such as weightlifting accidents.

• Penetrating Trauma: These precipitate injuries through stabbing or gunshot wounds. Approximately three to six percent of tracheobronchial injuries are attributed to penetrating causes. Stab wounds can result in punctures or lacerations, while gunshot wounds typically inflict severe damage. Overall, penetrating injuries pose a higher likelihood of causing tracheobronchial injuries, particularly in the neck region, compared to blunt trauma. Furthermore, injuries to the tracheobronchial system can also occur due to inhaling chemicals or harmful substances.

What Is the Clinical Presentation of Tracheobronchial Injury?

The clinical presentation of tracheobronchial injuries can vary from subtle to life-threatening. Penetrating traumas are typically easier to identify, whereas blunt traumas pose diagnostic challenges.

Common symptoms include:

• High-pitched respiratory sounds characterize Stridor.

• Subcutaneous emphysema, where air becomes trapped under the skin.

• Hemoptysis, or coughing up blood

• Approximately 60 percent of cases exhibit air leakage from the wound.

• Changes in voice, difficulty speaking, and hoarseness may indicate damage to the voice box or surrounding nerves.

• Coughing.

• Mediastinal emphysema, characterized by air in the chest cavity between the lungs, can also occur.

• In such cases, Hamman's sign, an abnormal crunching sound synchronized with the heartbeat, may be evident.

In instances of blunt trauma, symptoms may not manifest immediately. In fact, up to a third of neck tracheal injuries might initially present without symptoms but could become more apparent over the following day or two.

What Imaging Modalities Are Used in Diagnosing Tracheobronchial Injury?

When a patient arrives in the emergency room, the first diagnostic step typically involves a chest X-ray. This initial imaging test is crucial for identifying conditions such as pneumothorax, where air accumulates outside the lungs, occurring in approximately 70 percent of cases.

Diagnostic tests encompass various modalities, including:

• Chest X-rays: These reveal pneumothorax, subcutaneous emphysema, and pneumomediastinum, indicative of chest airway injuries. The "fallen lung sign of Kumpe” depicts lung displacement due to bronchial disruption.

• CT (Computed Tomography) Scan: For stable patients with intact airways, a CT scan with contrast dye of the neck and chest offers valuable insights, especially for laryngeal injuries. This imaging modality can detect chest bone fractures, pneumopericardium (presence of air or gas within the pericardial sac, which is the fibrous sac surrounding the heart), pneumothorax, and mediastinal hematomas (collections of blood that occur within the central compartment of the thoracic cavity).

• Fiberoptic Bronchoscopy: In critical scenarios, fiberoptic bronchoscopy secures the airway and visualizes injuries using a camera-equipped bronchoscope.

• CT Bronchography or Virtual Bronchography: These provide three-dimensional views of the tracheobronchial tree using CT scans. Esophageal injuries often co-occur with these conditions, warranting additional investigations, such as esophagogastroduodenoscopy or contrast esophagography, for a comprehensive evaluation.

What Is the Management of Tracheobronchial Injury?

Prioritizing the patient's safety, the initial crucial action entails securing their airway to ensure proper breathing and oxygenation. Surgical intervention becomes necessary when faced with substantial blood accumulation within the chest, airway perforations exceeding two centimeters in diameter, or persistent air leakage into the chest cavity despite chest tube placement.

1. Nonoperative Management: In cases where the injury is deemed less severe, typically involving less than 1.6 inches (four centimeters) of the trachea with less than one-third of its circumference affected and devoid of damaged tissue at the edges, conservative management may be appropriate. Conservative management becomes an option when the patient demonstrates stability, lacks serious infections, and sustains no severe neck injuries. The absence of signs indicating air leakage into surrounding tissues supports this approach, avoiding invasive interventions.

Conservative measures encompass maintaining the neck in a neutral position, minimizing verbal exertion, administering antibiotics, utilizing humidified air, and employing medications to mitigate stomach acid production. Follow-up bronchoscopy assessments are essential for monitoring the healing process and ensuring therapeutic efficacy. In select cases, tracheal stenting may be considered, involving the placement of tube-like stents within the airway to prevent collapse and inserting a tracheostomy tube to maintain airway patency.

2. Operative Management: Immediate action is warranted when the patient's condition is unstable. In cases of blunt injury, meticulous insertion of a breathing tube is paramount, with emergency procedures like tracheostomy involving airway access through the throat being considered if intubation proves challenging.

Before the surgical intervention, patient stabilization takes precedence, necessitating careful cleansing and repair of the injured area. The choice of surgical incision is contingent upon the injury's location, typically positioned just above the notch at the base of the neck in a horizontal orientation. Median sternotomy is employed for injuries affecting the lower windpipe segment, facilitating optimal visualization for meticulous tissue removal and suturing of lacerated membranes.

Resection and reconstruction are often preferred for extensive injuries, with some experts advocating for the removal and rebuilding of up to half the trachea's length. However, individual suitability varies due to anatomical differences. Concomitant assessments for esophageal injuries and nearby blood vessels are conducted, with damaged areas meticulously sutured. Severe injuries involving the lower main bronchi may necessitate lobectomy rather than attempted repair, followed by thorough rinsing and the potential placement of a drainage tube. In instances where only the windpipe sustains injury in the neck, a drainage tube may not be required post-surgery. Following the procedure, patients are advised to maintain a slight forward neck tilt to alleviate pressure on the repair site, facilitating optimal healing. After windpipe repair, ensuring proper placement of the breathing tube beyond the repaired area is imperative to prevent undue pressure during respiration.

Conclusion

In summary, traumatic tracheobronchial injury represents a critical condition demanding swift identification and tailored intervention to mitigate potential complications and enhance patient prognosis. Through heightened clinical awareness and access to cutting-edge diagnostic tools and surgical methodologies, medical practitioners are empowered to deliver timely and thorough treatment, fostering improved recovery prospects and sustained patient wellness in the long run.