Chapter 57: Endoscopic Therapy for Endobronchial Lesions

INTRODUCTION

Central airway obstruction (CAO) is caused by a variety of benign and malignant diseases. In general, a tracheal luminal diameter less than 8 mm will result in exertional dyspneic symptoms and audible stridor; symptoms occur at rest at less than 5 mm.¹ Sticky secretions or a mucus plug at the stenotic area may result in the patient potentially becoming symptomatic, even with a tracheal diameter larger than 8 mm, which may become life-threatening. Restoration of airway patency is associated with improvement in symptoms, quality of life, and lung function.² The treatment of malignant CAO is often a multimodality approach and is usually performed for palliation of symptoms in advanced lung cancer. In contrast, benign CAO disease pathogenesis per se does not influence the patient’s prognosis. Therefore, a more curative intervention option is required, including resection and reconstruction of the airway with an expert team. This chapter reviews currently available endotracheal and endobronchial techniques for the management of CAO in various settings, including balloon tracheobronchoplasty, mechanical airway dilation and core-out, electrocautery, argon plasma coagulation, laser therapy, photodynamic therapy, cryotherapy, brachytherapy, and airway stents. All CAO cases are challenging for the physician. Treatment options will be determined by expertise and available equipment in each institution.

ETIOLOGY

The exact prevalence of CAO is unknown. Approximately one-third of patients with lung cancer develop airway obstructions,³ and many other cancers lead to airway obstruction through metastases or direct invasion of the airway.⁴ Lung cancer is the leading cause of cancer death in the United States. With the rising number of lung cancer cases, the prevalence of malignant CAO has increased. Benign CAO covers a broad scope of diseases, and there are no precise epidemiological data specifying its prevalence.⁵ The most common CAO, tracheal stenosis, results from previous intubation or tracheostomy tube, idiopathic subglottic stenosis, and tracheobronchomalacia. The prevalence of benign CAO is expected to increase in future as the number of lung transplantations grow.⁶

CLINICAL PRESENTATION

The relationship between the degree of airway obstruction and the patient’s symptoms is not entirely clear because of the multiple variables of underlying diseases and health conditions. There are no unique symptoms that distinguish CAO. Dyspnea, stridor, wheezing, cough, difficulty in clearing secretions, hemoptysis, and fever are almost universal signs. Dyspneic perception; related and multiple variables such as muscle strength, chest wall compliance, lung elasticity, metabolic demands, and pain; and a variety of underlying cardiopulmonary and renal diseases may affect the diagnosis. Patients are sometimes misdiagnosed owing to the exacerbation of chronic obstructive pulmonary disease or asthma symptoms such as wheezing, which improve after treatment of the superimposed infection. Idiopathic subglottic stenosis cases are often treated as long-time asthma. Recently, asymptomatic CAO has also been encountered due to the increased use of computed tomography.⁷

INITIAL STABILIZATION AND MANAGEMENT

Airway ...