Postural-ventilatory coordination is altered in COPD individuals during ventilatory maneuvers

Background: Chronic obstructive pulmonary disease (COPD) is an endemic disease affecting the respiratory system and is also accompanied by postural control impairment, increased risk of falls, and reduced quality of life. The mechanisms related to balance control in this population remain unclear. Research question: The present study aims to investigate the postural-ventilatory coupling in individuals with COPD and to establish its relationship with the clinical and functional status of this population. Methods: Eighteen individuals with moderate (N=8) and severe (N=10) COPD groups and healthy age-matched participants (N=10) were enrolled. All participants performed the following tasks in upright position: (1) maintain the usual ventilatory pattern (eupnea); (2) adopt the metronome-guided hyperventilation pattern (tachypnea). A single 40-s trial was performed for each task. Postural sway was assessed by the anterior-posterior coordinates of center-of-pressure (CP) as acquired using a force platform. Ventilation movements were synchronously registered through a thoracic belt. A two-way ANOVA was used to compare groups vs. tasks, assuming an alpha level of 5%. Results: There was no difference in the control and COPD groups regarding physical and functional status (P-value >0.208). However, a significant group effect was found for the temporal shift of postural-ventilatory coupling (F=11.357, P<0.001, 2=0.476); specifically, the moderate COPD group exhibited a larger delay between ventilatory movements and postural sway (post-test P<0.001). There was no relationship between postural-ventilatory coupling measures and the clinical and functional status of COPD individuals. Significance: COPD is related to changes in postural-ventilatory coupling depending on the severity of the disease. This phenomenon could possibly explain the postural impairment usually observed in this population.