Abstract
COPD patients usually present thoracoabdominal asynchrony (TAA) that is considered as clinically relevant. Although there are several TAA estimation techniques, there is no consensus about which is the most appropriate to measure it. AIM: to compare two TAA quantification techniques in COPD patients at rest and during exercise. METHODS: 22 severe and very severe COPD patients (FEV1 40.2±10.5%pred) were assessed by optoelectronic plethysmography at rest and at mild (unload) and moderate (70% maximum workload) exercise in a cycle ergometer. TAA was estimated by the phase angle (PA) through Lissajous approach and by the percentage of time of paradoxical motion (PM). Also, TAA was calculated among all 3 compartments: upper (URC) and lower ribcage (LRC) and abdomen (AB). PM percentage values were expressed in a scale ranging from 0 to 180° to permit comparison with PA. Positive TAA values represent that the superior compartment is leading relative to the inferior. Two-way repeated measure ANOVA and the Holm-Sidak method were used. RESULTS: PM and PA techniques estimated differently TAA during mild exercise between URC-AB (respectively, -15.5±34.2° vs. -7.57±15.2°; p<0.05) and LRC-AB (-59.8±36.1° vs. -37.7±37.9°; p<0.05) and moderate exercise between URC-AB (-14.6±29.9° vs. -4.56±13.1°; p<0.05). Also, it was observed that using PM technique, TAA increased during mild exercise between LRC-AB (-59.8±36.1°; p<0.05) and moderate exercise between URC-LRC (54.1±43.7°; p<0.05) and LRC-AB (-54.5±37.1°; p<0.05) when compared to rest. CONCLUSION: PA and PM differently quantify thoracoabdominal asynchrony in COPD patients. It is important to consider the technique during respiratory evaluation in this population.
- © 2014 ERS
