Keywords
bronchial avulsion - tension pneumothorax - pediatric trauma - blunt thoracic trauma
New Insights and the Importance for the Pediatric Surgeon
The combination of air leak after thoracostomy and subcutaneous emphysema should be
considered bronchial injury until proven otherwise. Our technique of placing a retraction
suture on the upper rim of the defect allows the surgeon to temporarily occlude the
defect with a finger while, at the same time, facilitating ventilation of the contralateral
lung.
Introduction
Thoracic trauma is a rare condition, seen in only 13% of pediatric trauma patients.
More than 80% of the affected patients suffer from severe combined injuries after
road traffic injuries or a fall.[1] Pulmonary contusion or rib fractures are the most common findings in the pediatric
population (50% of cases), followed by pneumothorax in around 37% of patients.[1] In contrast, traumatic tracheobronchial injury is exceptionally rare, present in
only 0.05 to 3% of cases.[1]
[2] Clinical signs vary or may be misleading,[1] making these injuries hard to diagnose. Traumatic airway disruption is a potentially
lethal condition with mortality up to 30%, with one half of these deaths occurring
during the first hour after trauma.[2]
[3]
Injury patterns after blunt thoracic trauma in children differ dramatically from those
of adults. The high elasticity of the thoracic wall in children transmits the impact
of external force on the intrathoracic and mediastinal organs with little external
signs of injury.[1]
[3] Associated rib fractures, for instance, are only seen in 25% of tracheobronchial
injuries.[2] Also, tension pneumothorax is three times more frequent in children compared with
adults, due to increased mobility of the mediastinum.[1]
In most cases of lower airway injuries, a simple bronchial repair is successful.[4] Tension-free anastomosis should be completed with interrupted sutures, tying the
knots outside the lumen.[2] More severe or combined injuries have been repaired successfully on cardiopulmonary
bypass.[5] Short-term complications include persistent bronchopleural fistulas and mediastinitis.[2] In due course, anastomotic stenosis can develop, so that follow-up bronchoscopy
is recommended for symptomatic patients. In such cases, conservative management with
endoscopic dilatations is possible.[4]
Case Report
A 7-year-old girl presented to our emergency department after horse riding accident.
Although the event was unwitnessed, most likely the patient fell off the horse and
was stepped onto the chest by one of the hind hoofs. At arrival in the trauma bay,
she was placed on a stretcher in prone position, chest propped up on the arms, displaying
signs of severe dyspnea with tachypnea, increased work of breathing, and both inspiratory
and expiratory stridor. Her oxygen saturation (SaO2) was stable around 90% after application of supplemental oxygen. The patient was
fully aware and conscious (Glasgow Coma Scale 15), but agitated. On physical examination,
there were bruises on the throat and right upper chest with massive subcutaneous emphysema
of the upper chest, neck, and face. The patient was given sedatives, leading to desaturation.
Still, there was no obvious difference in breath sounds on both sides, so bilateral
needle thoracostomy was performed, and the patient was endotracheally intubated ([Fig. 1A]). After intubation and positive-pressure ventilation, oxygen saturation and blood
pressure dropped. At this time, right tension pneumothorax was diagnosed, and two
17-mm thoracostomy tubes were placed.
Fig. 1 (A) Clinical appearance of the patient in the trauma bay after intubation and bilateral
needle thoracostomy; (B) computed tomography imaging displaying rupture of the right main stem bronchus (arrow),
massive soft tissue and mediastinal emphysema, and significant right pneumothorax
and in spite of drainage (*thoracostomy tube).
Diagnostic Assessment
A massive air leak was appreciated from the chest tubes ([Video 1]). The SaO2 improved to 84%. Computed tomography (CT) scan showed a complete avulsion of the
right main stem bronchus at the level of the carina, a residual pneumothorax with
mediastinal shifting, atelectasis of the right lung, as well as emphysema of the mediastinum
and soft tissue ([Fig. 1B]). The only skeletal thoracic injury was a fracture of the contralateral left first
rib. The blood gas showed acidosis (pH 7.16), and hypercapnia (partial pressure of
carbon dioxide 63 mm Hg).
Video 1
Massive air leak after application of negative pressure on the chest tubes.
Therapeutic Intervention
The patient was taken to the operating room immediately. With positive-pressure ventilation,
oxygen saturation dropped continuously in spite of two working thoracostomy tubes
and manual high frequency, low tidal ventilation. Single lung ventilation of the contralateral
lung was our primary approach for ventilation during thoracotomy. An attempt of bronchoscopy-guided
selective left main stem intubation failed because of impaired visualization due to
blood in the airway. During bronchoscopy, the patient desaturated (SaO2 <10% for 5 minutes, heart rate dropped to 60/min).
Intraoperative Course
The patient was placed in left lateral decubitus position and immediate, salvage posterolateral
thoracotomy was performed. The defect was identified at the level of the carina, leaving
no proximal bronchial stump to place a clamp. Temporary occlusion of the defect with
the surgeons' finger allowed some ventilation of the left lung to gradually improve
the oxygen saturation. Placing the finger on the defect, however, partially occluded
the left main bronchus at the same time, prohibiting selective intubation and sufficient
ventilation of the left lung. We decided to place a 3-0 polypropylene suture for retraction
at the caudal rim of the tracheal defect, which allowed simultaneous occlusion of
the defect and patency of the left main stem bronchus. Hence, intubation under visual
and tactile guidance with a preloaded 5.0 tube, using bronchoscope as “guidewire,”
was possible ([Fig. 2]). After cardiorespiratory stabilization, the reconstruction of the bronchus was
performed. The anastomosis was completed with a posterior running 3-0 polypropylene.
The anterior wall was closed with interrupted sutures knotted outside the lumen. There
was no tension on the anastomosis and no air leak at under-water testing. A single
chest tubes was left in place postoperatively.
Fig. 2 Intraoperative placement of traction suture at the caudal tracheal rim of the defect,
allowing simultaneous occlusion of the defect and patency of the left main stem bronchus.
Postoperative Course
After surgery, pressure-controlled ventilation was continued on the intensive care
unit. Broad-spectrum antibiotics were administered. Body temperature was lowered to
35°C over a period of 48 hours for neuroprotection. On the second postoperative day,
bronchoscopy was performed showing an intact anastomosis, so that the breathing tube
was retracted into the trachea 2 cm above the level of the carina. The patient was
extubated on postoperative day 7 and discharged from the hospital on postoperative
day 24 after weaning of sedatives and antimicrobial treatment of colonization of the
trachea with Enterobacter cloacae according to our microbiologists' protocol. On physical examination, an alar scapula
persisted. Neurologic exam was unremarkable.
Discussion
Severe thoracic injury after trauma is rare in young children, but may lead to significant
morbidity or even death within a short period of time after trauma. After thoracic
trauma, clinical signs like subcutaneous emphysema and massive air leak in the thoracostomy
tube are indicative of tracheobronchial disruption. These symptoms are infrequently
encountered by clinicians, which may lead to delayed recognition and treatment.
Intubation of our patient before placing a chest tube led to life-threatening decompensation.
In a patient with suspected bronchial injury, positive-pressure ventilation should
be avoided whenever possible because it may exacerbate the pneumothorax. When a single
chest tube does not provide adequate decompression of a pneumothorax, a second chest
tube should be placed. A large, ongoing air leak in combination with progressive subcutaneous
emphysema is highly suspicious of relevant airway injury. Clinicians need to be aware
of this cluster of symptoms.
In most cases, plain chest radiograph is recommended for pediatric patients with thoracic
trauma, revealing relevant fractures, pneumothorax, and mediastinal pathologies that
need to be addressed immediately.[1] There is no consensus about the primary use of chest CT in this group. Even though
CT scan might have a higher sensitivity for pathologies like lung contusion or a small
pneumothorax, these additional findings rarely lead to a change in management.[1]
[6] The cancer risk after thoracic CT in childhood is estimated as 25/10,000 for girls
and 7.5/10, 000 for boys.[7] Therefore, some authors argue that CT of the thorax should be considered only in
patients with pathological findings on plain film X-ray.[6] In our particular case, a primary CT was obtained after stabilization of the patient,
which was helpful in locating the injury preoperatively.
Intraoperatively, clamping of the bronchial avulsion was impossible due to the proximal
injury at the carina. Temporary occlusion of the tracheal defect was possible, but
partially occluded the remaining intact left bronchus at the same time. Only after
placement of a traction suture at the rim of the defect, it was possible to manually
direct the tube into the left bronchus and secure ventilation. Inability to clamp
the defect must be anticipated in situations like these, since 80% of tracheobronchial
injuries occur within 2.5 cm of the tracheal bifurcation by entrapment of the airway
between the sternum and the vertebral column.[2] Therefore, our technique employing a traction stitch may be helpful and life-saving
in similar cases.
Thoracotomy and primary anastomosis without further measures are the main surgical
approach for tracheobronchial injury in children[2] and adults.[8] Both running or interrupted sutures are used, according to the literature.[2]
[8]
[9] Risk factors for anastomotic leakage include inadequate suture pitches, discrepancy
of the bronchial diameter, high tension on the anastomosis, and poor visualization
of the operative field.[9] Intercostal muscle flap,[8] suture holders,[9] or bronchial plication of the membranous portion of the bronchus in cases of discrepancy
of the bronchial diameter[10] may be used to reduce the risk of complication in a stable patient.
Conclusion
Even though tracheobronchial injuries in children are extremely rare, they require
urgent intervention. The combination of air leak after thoracostomy and subcutaneous
emphysema should be considered bronchial injury until proven otherwise. In these cases,
intubation may lead to respiratory deterioration and should be postponed in a patient
with sufficient respiratory compensation until a chest tube is in place and the patient
is in a controlled environment, such as the operating room, where thoracotomy can
be performed immediately. Finally, our technique of placing a retraction suture on
the upper rim of the defect allows the surgeon to temporarily occlude the defect with
a finger while at the same time facilitating ventilation of the contralateral lung.
