Effects of positive pressure on tracheobronchomalacia and collapse reversal

INTRODUCTION: Symptoms in patients with Mounier-Kuhn Syndrome (MKS) may arise from associated tracheobronchomalacia (TBM). Although continuous positive airway pressure (CPAP) is a recognized therapeutic option, there are few evidences regarding its clinical effectiveness. This study aims to identify TBM in patients with MKS via bronchoscopy, evaluate whether CPAP can reverse airways collapse, and determine the optimal pressure. Furthermore, this research analyzes the impact of CPAP on pulmonary ventilation and investigates the prevalence of obstructive sleep apnea-hypopnea syndrome (OSAHS) within this population. METHODS: This is an open exploratory intervention study with involving patients diagnosed with MKS. Data collection included sociodemographic and clinical variables, alongside a review of previous diagnosis test. Patients underwent full-night polysomnography. Subsequently, bronchoscopy and electrical impedance tomography (EIT) were performed concurrently with CPAP titration to address airways collapse. For each affected region, the positive end-expiratory pressure (PEEP) level was determined using three methods: observational analysis during bronchoscopy "expert assessment"), post-hoc analysis of recorded bronchoscopy images ("objective assessment"), and EIT-based analysis "EIT-derived PEEP"). RESULTS: Twelve patients consented to participate. OSAHS was observed in 90%, and malacia in 91.66%. Twelve procedures were performed for CPAP titration (five in the tracheal and seven in the bronchi). Expiratory luminal area with PEEP 0 was smaller than the one with the PEEP selected based on the "objective assessment" (p-value < 0.001) and based on the "objective assessment" (p-value 0.002). EIT demonstrated changes in the distribution of pulmonary ventilation with CPAP. CONCLUSION: TBM is highly prevalent in patients with MKS. Positive pressure resulted in a significant increase in the airway expiratory luminal area and reversal of malacia. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov NCT03101059. Registration Date: 03/23/2017.