COPD Patients Have a Restricted Breathing Pattern That Persists with Increased Metabolic Demands.
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A healthy respiratory system has variability from breath-to-breath and patients with COPD (PwCOPD) have abnormal variability in breath cycles. The aim of this study was to determine if interbreath-interval and tidal-volume variability, and airflow regularity change as metabolic demands increase (seated, standing, and walking) in PwCOPD as compared to controls. Sixteen PwCOPD (64.37.9yr, 61.344.1% FEV1%predicted) and 21 controls (60.26.8yr, 97.516.8% FEV1%predicted) sat, stood, and walked at their preferred-pace for five-minutes each while breathing patterns were recorded. The mean, standard deviation, and coefficient of variation of interbreath-intervals and tidal-volume, and the regularity (sample entropy) of airflow were quantified. Results were subjected to ANOVA analysis. Interbreath-interval means were shorter in PwCOPD compared to controls (p=0.04) and as metabolic demand increased (p<0.0001), standard deviation was decreased in PwCOPD compared to controls during each condition (p's<0.002). Mean tidal-volume did decrease as metabolic demand increased across groups (p<0.0001). Coefficient of variation findings (p=0.002) indicated PwCOPD decline in tidal-volume variability from sitting to standing to walking; whereas, controls do not. There was an interaction for airflow (p=0.02) indicating that although, PwCOPD had a more regular airflow across all conditions, control's airflow became more irregular as metabolic demand increased. PwCOPD's airflow was always more regular compared to controls (p=0.006); although, airflow became more irregular as metabolic demand increased (p<0.0001). Healthy respiratory systems have variability and irregularity from breath-to-breath decreases with adaptation to demand. PwCOPD have more regular and restricted breathing pattern that may affect their ability to adjust in demanding situations.
author list (cited authors)
Yentes, J. M., Fallahtafti, F., Denton, W., & Rennard, S. I.
complete list of authors
Yentes, Jennifer M||Fallahtafti, Farahnaz||Denton, William||Rennard, Stephen I