Correspondence
Anjaly K.C., Kadiparambath House, Edappally North, Ponekkara, AIMS P.O., Kochi 682041, Kerala, India. Email: [email protected]
Key Words
Endobronchial tuberculosis, endo- bronchial stent, silicone stent, ECMO.
Financial and Competing Interest
No conflicts of interest declared.
Informed Consent
Written informed consent for the paper to be published (including images, case history and data) was obtained from the patient/guardian for publication of this paper, including the accompanying images.
ABSTRACT
Endobronchial tuberculosis (EBTB) is defined as tuberculous infection of the tracheobronchial tree with microbial and histopathological evidence. It is seen in 10-40% of patients with active pulmonary tuberculosis. More than 90% of the patients with EBTB have some degree of airway stenosis. Balloon dilatation and self-expanding stent insertion is an effective treatment for bronchial stenosis. Use of endobronchial stents should only be considered in lesions of proximal location when other dilatational methods have failed. Here, we report the use of emergency bedside extracorporeal membrane oxygenation (ECMO) as a salvage manoeuvre in a case of distal tracheal obstruction of a patient receiving treatment for EBTB, and tracheal stenting using silicone stents in a patient on ECMO support.
INTRODUCTION
Critical Narrowing of the upper airway, including the trachea, is a life- threatening emergency. Initial management will depend on the degree of obstruction, the level of obstruction, and the specific cause. Endotracheal intubation, emergency tracheostomy or cricothyroidotomy can be life-saving when an obstruction is at the level of the vocal cords or above. Total occlusion of the upper airway will rapidly lead to death unless such an obstruction is relieved. Stenotic lesions may require repeated dilatations.1 Jaiswal et al describe a case of tracheal stenosis following treatment for tuberculosis, in which the patient underwent serial dilatations. In order to maintain tracheal patency, stenting was also undertaken.² Historically, extracorporeal membrane oxygenation (ECMO) has been used primarily in cases of cardiac or respiratory failure. Over the last decade, ECMO has found increased utility in the form of short-term support in hypoxic patients undergoing upper airway surgery and complex tracheal operations. In this paper, we elucidate how ECMO helped as a rescue procedure for a patient who was inadequately ventilated. We discuss different types of tracheal stents and their complications.
CASE PRESENTATION
A case of 25 year old female, who is a staff nurse by profession, presented with a 5 month history of cough and hoarseness of voice, and a 1 week history of breathing difficulty and stridor. She had associated loss of appetite and weight loss. On examination of the chest, breath sounds were reduced on the right mammary area, with reduced VR. Blood investigations showed leucocytosis with neutrophilia and thrombocytosis. A chest x-ray showed right side mid zone homogenous opacity. A CT thorax showed right upper lobe collapse consolidation, and mucosal irregularity of the tracheae, with secretions plug- ging the right upper lobe bronchus (figure 1) and mediastinal adenopathy. Bronchoscopy showed tracheal stenosis below the vocal cords, extending up to the carina (figure 2). A scope could be just passed. The right main bronchus was pin-pointed. The mucosa appeared irregular, friable and edematous. The left sided bronchial tree was normal. A biopsy was taken from the sloughed area, which showed multiple necrotising granulomas. ZN stain showed acid fast bacilli. Analysis with GENEXPERT detected Mycobacterium tuberculosis with no rifampicin resistance detected. The patient was started on antitubercular therapy, having been diagnosed as a case of endobronchial tuberculosis. In view of the critical airway stenosis, it was decided to give a short course of steroids. The patient improved clinically with medical treatment, and hence was discharged. She was advised to continue ATT and the steroid was tapered off.
Following 2 months of ATT, the patient again presented with stridor and breathing difficulty. Bronchoscopy revealed mid tracheal stenosis, which was relieved using a tracheal knife and balloon dilatation. However, one month later, she presented with acute onset of stridor. At that time, she was tachypnoeic and had desaturation of up to 85%. She was admit- ted to the ICU. There, she developed respiratory acidosis, and after repeated attempts, she was intubated with a size 5 ET tube under bronchoscope guidance .As she was not adequately ventilated, even with a paediatric ET tube, it was decided to conduct emergency veno-venous ECMO (VV-ECMO) for temporary respiratory support until tracheal stent placement. Under local anaesthesia, after heparinization, 22Fr and 20 Fr Edwards cannula were placed through the right femoral vein and right internal jugular veins respectively. After cannula positions were confirmed by USG, VV-ECMO was established. The following day, on VV-ECMO support, the patient under- went rigid bronchoscopy. The trachea showed long segment stenosis. We dilated the trachea along the full length, coring out the fibrotic parts of the trachea using the rigid tube. Repeated dilatation was performed using a dilator through the rigid tube. Under the guidance of fluoroscopy, we stented the trachea with a size 14 silicon stent (9 cm long), with the help of a rigid bronchoscope with size 16 barrel. Later, a CT Thorax was taken, which showed the silicone stent in situ (figure 3). The patient was reintubated and, after 2 days, once the glottic edema had reduced, she was extubated. The next day she was weaned off from ECMO and underwent frequent surveillance bronchoscopies to assist with secretion clearance and assess for airway patency (figure 3). The patient was advised to continue ATT for 9 months.
After 4 months of tracheal stenting, a bronchoscopy revealed granulation tissue beneath the tracheal stent, and a severely compromised right main bronchus lumen. As there was critical narrowing of the right main bronchus, it was decided to undergo Y-stenting of the trachea and main bronchus. The patient was electively put on VV-ECMO. Under rigid bronchoscope guidance, the previous tracheal stent was removed, balloon dilatation of the right main bronchus was completed and a silicone Y-stent was successfully deployed. Post-procedure, ECMO was decannulated and the patient extubated and discharged with a tapering dose of steroids.
DISCUSSION
Tuberculous infection of the tracheobronchial tree is known as endobronchial tuberculosis (EBTB). In patients with active pulmonary tuberculosis, EBTB frequency ranges from 10−50%.3-6 It can occur with or without parenchymal involvement and is more common in young adults and females.5-6 EBTB is a distinct form of tuberculosis which continues to remain a diagnostic challenge, even in high TB prevalence countries. The chest X-ray in EBTB can appear normal, and diagnostic confirmation can only be achieved bronchoscopically. Bronchoscopy is pivotal to the diagnosis of EBTB. Endobronchial lesions have been categorised as actively caseating, oedematous-hyperaemic, fibrostenotic, tumorous, granular, ulcerative and non-specific bronchitic.7 Tracheal stenosis is not a frequent complication of Endobronchial TB. In many cases it will respond to anti- tuberculous drugs together with steroids, to suppress the in- flammation; however, additional measures are sometimes needed.
Dilatation seems an effective and safe treatment. Of 59 patients in one series, 83% reported a substantial improvement in symptoms.8 Complications were few, but recurrence was common. 80% of patients had a primary relapse of airway stenosis and 43% had a secondary relapse. Recurrence is the usual reason for stent insertion. Since retrieval of metallic stents can be difficult, non-metallic stents are preferred for the management of benign disease; they can be left in situ for long periods. There are 4 categories of airway stents9- silicone stents, balloon dilated metal stents, self-expanding metal stents (SEMS) and covered SEMS. The silicone Dumon stent (Novatech, Boston Medical, Massachusetts, USA) is widely popular and is often used to treat benign tracheal stenosis. Complications include stent migration (17%), granuloma formation (6%) and mucostasis (6%).10,11 We used a silicone stent for our patient, but she developed granuloma formation beneath the stent and maintained a recurrent cough, which prompted us to complete serial bronchoscopy and clearance.
To the best of our knowledge this is the first case reported from India on airway stenting completed while a patient was on ECMO. This patient’s long segment tracheal stenosis made oxygenation and ventilation impossible, prohibitively limiting the duration of each tracheobronchial intervention. Given the complexity of the necessary airway intervention and the time constraints imposed by the patient’s poor respiratory status, VV-ECMO was used without complication to support the patient during tracheobronchial intervention. The first case of non-cardiac surgical application of extracorporeal circulation was reported by Woods et al. in 1961.12 They used extracorporeal circulation for resection of the carina and both main stem bronchi for bronchial adenoma.
Kim et al have described application of a veno-venous type extracorporeal membrane oxygenator (ECMO) in high-risk tracheal procedures in six cases, including five patients with tracheal stenosis.13 During ECMO perfusion, the surgeons could concentrate on the procedure without worrying about patients’ oxygenation. However, ECMO also has its own risks, such as thromboembolism and bleeding due to anticoagulation. In our case, ECMO was established safely without complication. While conventional ventilation is sufficient for the vast major- ity of patients undergoing tracheobronchial intervention, a subset of patients cannot maintain respiratory function during intervention and can be safely bridged with ECMO support.
CONCLUSION
In patients with endobronchial tuberculosis, tracheal steno- sis is a dreaded complication which should be always kept in mind while starting treatment. Diagnostic confusion can occur as the symptoms can simulate major pulmonary disorders such as bronchial asthma and lung cancer. Antituberculosis chemotherapy remains the mainstay of treatment. The role of corticosteroids is controversial, and even with timely treat- ment, some patients eventually progress to tracheobronchial stenosis. Bronchoscopic-guided balloon dilatation can be done as a single procedure, or may require repeated staged events, and cryotherapy may help. Stents, preferably silicone stents, may be inserted to maintain airway patency. Should these measures fail, surgical options including bronchoplasty can be explored to help patients with debilitating stenosis. Other treatment options include sleeve resection, carinal resection, reconstruction of the bronchus or trachea and end-to-end anastomosis. This case highlights the use of ECMO as a salvage procedure and as an adjunct to the optimal management of a difficult airway when the patient cannot be adequately ventilated through an ET tube and when there is complete stenosis of the central airway.
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