Excessive Dynamic Airway Collapse of the Lower Airway: A Cause for Persistent Sleep Disordered Breathing after Tracheostomy.

ABSTRACT: Tracheostomy has demonstrated effectiveness in the control of obstructive sleep apnea (OSA) in most patients; however, current evidence suggests significant sleep disordered breathing may persist, particularly in morbidly obese individuals. While several mechanisms have been proposed to explain this phenomenon, we demonstrate evidence of a previously unidentified pathophysiology: excessive dynamic airway collapse (EDAC) of the lower airway. We present the case of a 62-year-old woman status post tracheostomy with persistent dyspnea in the supine position. Both radiographic and bronchoscopic images demonstrate prolapse of the posterior membranous trachea at the level of the trachea and mainstem bronchi with partial or complete obstruction. The prolapse was completely relieved with upright positioning or positive airway pressure. This case illustrates a novel mechanism of post-tracheostomy sleep disordered breathing in obese individuals and emphasizes the need to consider follow-up polysomnography after tracheostomy in this patient population, especially those with persistent symptoms related to sleep or the supine position.