Background: Determining the presence of thoracoabdominal asynchrony in chronic obstructive pulmonary disease patients is clinically relevant, but there is no consensus on the optimal parameters for performing this analysis. Methods: We assessed 22 COPD patients (FEV1 40±10% predicted) and 13 healthy controls during rest and exercise with optoelectronic plethysmography (70% maximum workload) on a cycle ergometer. Thoracoabdominal asynchrony was calculated by using phase angle and phase shift parameters following a three-compartment model involving the upper and lower ribcages and abdomen. Patients were classified as having thoracoabdominal asynchrony (TAA+) or not (TAA-) based on control values (mean±2 standard deviations). The chest wall volume and compartmental contribution were also measured. Results: Thoracoabdominal asynchrony was observed in the lower ribcage. The phase angle detected more TAA+ patients at rest (15 vs. 7 patients) and during exercise (14 vs. 8 patients) compared to the phase shift. TAA+ patients also presented a lower chest wall volume, lower ribcage contribution, and higher abdominal contribution to chest wall volume compared to the control and TAA- patients. Conclusion: Thoracoabdominal asynchrony was more detectable during rest and exercise using the phase angle parameter, and it was observed in the lower ribcage compartment, reducing the chest wall volume during exercise in patients with COPD.
- thoracoabdominal asynchrony
- chronic obstructive pulmonary disease
- air trapping
- chest wall
- Copyright © 2016, Journal of Applied Physiology