Association between inspiratory muscle weakness and slowed oxygen uptake kinetics in patients with chronic obstructive pulmonary disease

INTRODUCTION: Patients with chronic obstructive pulmonary disease (COPD) may have poor inspiratory muscle function, which reduces minute and alveolar ventilation, leading to increased hypoxemia and slow pulmonary oxygen uptake ( O2) kinetics. However, little is known about the effect of inspiratory muscle weakness (IMW) on oxygen uptake kinetics in patients with COPD. Thus, we tested the hypothesis that COPD patients with IMW have slowed O2 kinetics. METHODS: An observational study was conducted including COPD patients with moderate to severe airflow limitation and a history of intolerance to exercise. Participants were divided into two groups: (IMW+; n = 22) (IMW-; n = 23) of muscle weakness. RESULTS: Maximal inspiratory (PImax), maximal expiratory (PEmax), maximal sustained inspiratory (PImaxsustained), and maximal endurance inspiratory muscle strength were lower in IMW+ patients (36 ± 9.5 cmH2O; 52 ± 14 cmH2O; 20 ± 6.5 cmH2O; 94 ± 84 s, respectively) than in IMW- patients (88 ± 12 cmH2O; 97 ± 28 cmH2O;...