PT - JOURNAL ARTICLE AU - Masashi Shiraishi AU - Yuji Higashimoto AU - Ryuji Sugiya AU - Hiroki Mizusawa AU - Yu Takeda AU - Shuhei Hujita AU - Osamu Nishiyama AU - Shintarou Kudo AU - Tamotsu Kimura AU - Yasutaka Chiba AU - Kanji Fukuda AU - Yuji Tohda TI - Diaphragmatic excursion correlates with exercise capacity and dynamic hyperinflation in COPD patients AID - 10.1183/23120541.00589-2020 DP - 2020 Jan 01 TA - ERJ Open Research PG - 00589-2020 4099 - http://openres.ersjournals.com/content/early/2020/09/24/23120541.00589-2020.short 4100 - http://openres.ersjournals.com/content/early/2020/09/24/23120541.00589-2020.full AB - Background Although the pathophysiological mechanisms involved in the development of dyspnoea and poor exercise tolerance in patients with chronic obstructive pulmonary disease (COPD) are complex, dynamic lung hyperinflation (DLH) plays a central role. Diaphragmatic excursions can be measured by ultrasonography (US) with high intra- and interobserver reliability. The objective of this study was to evaluate the effect of diaphragmatic excursions as assessed by US on exercise tolerance and DLH in patients with COPD.Methods Patients with COPD (n=20) and age-matched control subjects (n=20) underwent US, which was used to determine the maximum level of diaphragmatic excursion (DEmax). Ventilation parameters, including the change in inspiratory capacity (ΔIC), were measured in the subjects during cardiopulmonary exercise testing (CPET). We examined the correlations between DEmax and the ventilation parameters.Results The DEmax of patients with COPD was significantly lower than that of the controls (45.0±12.8 mm versus 64.6±6.3 mm, respectively; p<0.01). The perception of peak dyspnoea (Borg scale) was significantly negatively correlated with DEmax in patients with COPD. During CPET, oxygen uptake/weight (VO2/W) and minute ventilation (VE) were significantly positively correlated with DEmax, while VE/VO2 and VE/carbon dioxide output (VCO2) were significantly negatively correlated with DEmax in patients with COPD. DEmax was also significantly positively correlated with ΔIC, reflecting DLH, and with VO2/W, reflecting exercise capacity.Conclusion Reduced mobility of the diaphragm was related to decreased exercise capacity and increased dyspnoea due to dynamic lung hyperinflation in COPD patients.FootnotesThis manuscript has recently been accepted for publication in the ERJ Open Research. It is published here in its accepted form prior to copyediting and typesetting by our production team. After these production processes are complete and the authors have approved the resulting proofs, the article will move to the latest issue of the ERJOR online. Please open or download the PDF to view this article.Conflict of interest: Dr. Shiraishi has nothing to disclose.Conflict of interest: Dr. Higashimoto has nothing to disclose.Conflict of interest: Dr. Sugiya has nothing to disclose.Conflict of interest: Dr. Mizusawa has nothing to disclose.Conflict of interest: Dr. Takeda has nothing to disclose.Conflict of interest: Dr. Hujita has nothing to disclose.Conflict of interest: Dr. Nishiyama has nothing to disclose.Conflict of interest: Dr. Kudo has nothing to disclose.Conflict of interest: Dr. Kimura has nothing to disclose.Conflict of interest: Dr. Chiba has nothing to disclose.Conflict of interest: Dr. Fukuda has nothing to disclose.Conflict of interest: Dr. Tohda reports grants from Kyorin pharmaceutical, grants from MeijiSeika pharma, grants from Boellringer Ingelheim, grants from Teijin pharma, grants from DaiichiSankyo, grants from Astellas,Pearl, outside the submitted work;.