Implications of an aortic arch endoprosthesis on tracheal anatomy are underrecognized, especially given their close anatomic relationship. We present a unique case of an elderly woman who suffered an iatrogenic tracheal injury due to both an aberrant aortic arch anatomy and a thoracic endoprosthesis.
Departments of †Anesthesia, Critical Care and Pain Medicine
‡Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA
Disclosure: There is no conflict of interest or other disclosures.
Reprints: Omair Shakil, MD, Department of Anesthesia, Critical Care and Pain Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, One Deaconess Road, CC-470, Boston, MA 02215. (e-mail: email@example.com).
Received March 19, 2013
Accepted November 12, 2013
The implications of an aortic arch endoprosthesis on tracheal anatomy are underrecognized, especially given the close anatomic relationship between the 2 structures. This might put patients with aortic arch endoprostheses at increased risk for tracheal injury during the procedures involving instrumentation of the endobronchial tree, such as endotracheal intubation.1 We present a unique case of an elderly woman who suffered an iatrogenic tracheal injury during intubation with double-lumen endotracheal tube because of both, aberrant aortic arch anatomy and the presence of a thoracic endoprosthesis.
An 84-year-old woman was scheduled for a video-assisted thoracic surgery for a left hemothorax washout. Before this admission, she had undergone an emergent repair of a type B aortic dissection. Computed tomographic angiography (CTA) confirmed a ruptured pseudoaneurysm at the beginning of the descending thoracic aorta. Of note, the patient had an acute-angled right-sided aortic arch (RAA) with mirror image branching (Fig. 1). A 31×15, 31×10, and a 37×10 Gore TAG Thoracic endoprostheses (W.L. Gore & Associates Inc., AZ) were placed. The patient had tolerated that procedure well and was discharged home on the sixth postoperative day.
One week later the patient was readmitted with complaints of generalized weakness, worsening nonproductive cough, dyspnea, abdominal pain, and low-grade fever. A CTA revealed an endoleak into the left hemithorax. When an 18 Fr chest tube failed to satisfactorily drain the collection, she was scheduled for video-assisted thoracic surgery and a washout.
After induction, the patient was intubated with a 37 Fr double-lumen endotracheal tube: the bronchial lumen was passed through the cords, turned left 90 degrees, and advanced until resistance was felt. Conventional mechanical ventilation was initiated, and anesthesia was maintained with sevoflurane in 100% oxygen. The position of the endotracheal tube for single lung ventilation was confirmed bronchoscopically. A small laceration was also observed in the proximal left main-stem (LMS) bronchus. The interventional pulmonology service confirmed a full-thickness perforation in the medial LMS bronchus along the posterior membranous wall 5 mm from the carina and extending 1.2 cm distally. The options of conservative management (antibiotics and observation) or surgical repair were discussed with the patient’s daughter who opted for the latter. The surgical team proceeded with a primary repair of the LMS bronchus tear and drainage of the left hemothorax by a left thoracotomy. The patient remained intubated following the procedure and was transferred to the intensive care unit, where she was extubated on postoperative day 1. After the patient’s clinical condition improved, she was transferred to the floor on postoperative day 5, and discharged from the hospital for home on postoperative day 9 in a stable condition.
Tracheal injury is a rare but potentially fatal complication of endotracheal intubation.1 Risk factors may be related to the patient, procedure, or the technique.1,2 Patient-related risk factors include sex (women have a narrower airway),3 anatomic abnormalities (RAA),4 and pathologies (aneurysms).5 Procedure-related risk factors include attachment of the tube to the oxygen source, cuff placement (increased pressure in the airway), patient movement, stimulation of the cough reflex,2 as well as technical errors such as overinflation of the cuff.6 The most common injury is a longitudinal tear through the membranous portion of the trachea.6 A high degree of suspicion must be maintained, as patients can remain asymptomatic before developing frank respiratory insufficiency. Patient management can be conservative (antibiotics and serial imaging) or surgical, in suitable operative candidates.1,7 In addition to being female, our patient had 2 very uncommon factors that might have predisposed her to iatrogenic tracheal injury: an RAA and an endovascular stent.
Endovascular stenting has not previously been described as a risk factor for tracheal injury. On the basis of the appearance of the reconstructed CTA (Fig. 2), we believe that the stent created an immobile obstacle that occluded the trachea and prevented our endotracheal tube from navigating the angle, thus injuring the carinal wall. The position of this stent was complicated by the anatomy of the aorta. An RAA is a rare congenital malformation, with an incidence of 0.1%.8 An RAA with mirror image branching develops between the fourth and fifth week of embryological development: the double aortic arch encircling the esophagus and the trachea loses its right-sided branches, leaving behind only left-sided branches.9 A disruption in the left arch, between the left subclavian artery and the descending aorta, leads to the development of an RAA that lies to the right of the trachea and the esophagus with 3 branches: (proximal to distal) brachiocephalic artery, right common carotid artery, and the right subclavian artery.10 The RAA can lie in either a pretracheal or retroesophageal position; the ensuing vascular ring formations can have important implications for adjacent thoracic viscera.10
We believe our initial error was during preoperative assessment and underestimation of the extent of tracheal deviation, as marginally visualized on chest x-ray and better seen on reconstructed computed tomography cans, which were not available at the time. Had we incorporated this knowledge into our planning, we believe we might have been able to prevent this injury. One option would be to place the bronchial lumen through the vocal cords, place a bronchoscope in either the bronchial or tracheal lumen, and guide the double-lumen tube into position under direct vision. At a minimum, we believe this would have potentially allowed us to identify distorted anatomy and abort the placement of the double-lumen tube. From our experience, we suggest a detailed preoperative radiologic assessment of the airways before airway instrumentation in patients with thoracic endoprosthesis.
Our case highlights the implications of placing an aortic arch endoprosthesis from an anesthetist’s perspective. To the best of our knowledge, this is the first case where an aortic arch endoprosthesis appeared to contribute to iatrogenic tracheal injury. In the best interests of our patients, it would serve us well if we stay cognizant of this association.
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