Phillips DB; Domnik NJ; Elbehairy AF; Preston ME; Milne KM; James MD; Vincent SG; Ibrahim-Masthan M; Neder JA; O’Donnell DE;
Respiratory physiology & neurobiology [Respir Physiol Neurobiol] 2020 Nov 05, pp. 103571. Date of Electronic Publication: 2020 Nov 05.
Background: The purpose of this study was to determine if altered central chemoreceptor characteristics contributed to the elevated ventilation relative to carbon dioxide production (V̇ E /V̇CO 2 ) response during exercise in mild chronic obstructive pulmonary disease (COPD).
Methods: Twenty-nine mild COPD and 19 healthy age-matched control participants undertook lung function testing followed by symptom-limited incremental cardiopulmonary exercise testing (CPET). On a separate day, basal (non-chemoreflex) ventilation (V̇ EB ), the central chemoreflex ventilatory recruitment threshold for CO 2 (VRTCO 2 ), and central chemoreflex sensitivity (V̇ ES ) were assessed using the modified Duffin’s CO 2 rebreathing method. Resting arterialized blood gas data were also obtained.
Results: At standardized exercise intensities, absolute V̇ E and V̇ E /V̇CO 2 were consistently elevated and the end-tidal partial pressure of CO 2 was relatively decreased in mild COPD versus controls (all p < 0.05). There were no between-group differences in resting arterialized blood gas parameters, basal V̇ E , VRTCO 2 , or V̇ ES (all p > 0.05).
Conclusion: These data have established that excessive exercise ventilation in mild COPD is not explained by altered central chemosensitivity.