Efficacy of nasal high flow therapy on the coordination between breathing and swallowing of saliva during daytime nap in chronic obstructive pulmonary disease patients: A single center, randomized crossover controlled study.

Background: There are some clinical reports on dysphagia in patients with chronic obstructive pulmonary disease (COPD); however, its pathophysiology remains largely unknown.Changes in respiratory function occur in patients with COPD causing a decrease in tidal volume and an increase in respiratory rate (tachypnea). In addition, it leads to lack of coordination between respiration and swallowing.A new treatment called nasal high flow (NHF) has been introduced for patients with COPD, replacing the traditional non-invasive ventilation (NIV) procedure. The NHF therapy involves inhalation of high flow of humidified air, which reduces respiratory effort in patients with COPD. Furthermore, NHF therapy facilitates swallowing of saliva even during respiratory management. A recent clinical study reported that high-flow nasal cannula oxygen therapy for 6 weeks improved the health-related quality of life and reduced hypercapnia in patients with stable COPD. Taken together, NHF therapy is gaining attention in the clinical management of patients with COPD.Therefore, in this study, we aim to examine the efficacy of NHF therapy on the coordination between breathing and swallowing of saliva during daytime nap in patients with COPD.

Methods/design: This open-label, investigator-initiated, single center study will evaluate the efficacy of NHF therapy on the coordination between breathing and swallowing of saliva during the daytime nap in COPD patients with forced expiratory volume in 1 second (FEV1%) of <70% during treatment at the Nagasaki University Hospital Respiratory Rehabilitation Center. Evaluations will be performed during the 90 to 180 minute "daytime nap" in the measurement room of the hospital. The primary endpoint will be the rate of appearance of the expiratory phase after swallowing of saliva and the frequency of swallowing during the measurement period.

Discussion: The purpose of this study is to obtain evidence regarding the utility of NHF as a potential therapeutic device for COPD patients to prevent aspiration of saliva during the sleep stage of daytime nap. The utility will be assessed by comparing the decrease in incidence rates of the expiratory phase after swallowing of saliva in the NHF device group and the control group, wherein this device was not used.