Effect of ambulatory continuous positive airway pressure on neural respiratory drive and functional capacity in excessive dynamic airway collapse

Excessive dynamic airway collapse (EDAC) and tracheobronchomalacia (TBM) occur due to weakening of the walls of the central airways leading to airway collapse on expiration. The aim of this study was to investigate the effect of ambulatory continuous positive airway pressure (CPAP) on neural respiratory drive and exercise capacity. Patients with CT or bronchoscopic evidence of EDAC or TBM underwent baseline testing and 6-minute walk test (6MWT). Physiological testing was performed with patients self-ventilating and on CPAP at 4, 7 and 10 cmH2O to identify optimal ambulatory CPAP pressure. Patients then underwent repeat 6MWT on sham or active CPAP in a random order. Neural respiratory drive index (NRDI) was assessed by surface electromyography of the parasternal intercostals (EMGpara%max x respiratory rate). We studied 19 (8 male), ambulatory adult patients with EDAC and/or TBM: age 60±13years and BMI 34.5±6.5kg/m2. The NRDI was 346±182AU self-ventilating with unloading of the respiratory muscles with CPAP (delta -125±116AU; p In conclusion, ambulatory CPAP reduces neural respiratory drive and increases exercise capacity in patients with EDAC/TBM.