Clinical Assessment of Peripheral Muscle Function in Patients with Chronic Obstructive Pulmonary Disease
Vilaro, Jordi × Rabinovich, Roberto Manuel Gonzalez-deSuso, Jose Troosters, Thierry Rodriguez, Diego Albert Barbera, Joan Roca, Josep #
Published by Williams & Wilkins for the Association of Academic Physiatrists
American Journal of Physical Medicine & Rehabilitation vol:88 issue:1 pages:39-46
Vilaro J, Rabinovich R, Gonzalez-deSuso JM, Troosters T, Rodríguez D, Barberà JA, and Roca J: Clinical assessment of peripheral muscle function in patients with chronic obstructive pulmonary disease. Am J Phys Med Rehabil 2008;87:***-***. OBJECTIVE:: Correlation of muscle function, muscle mass and endurance, and exercise tolerance in chronic obstructive pulmonary disease (COPD). DESIGN:: Sixteen COPD patients (forced expiratory volume during the first second 38 +/- 15% predicted) and 6 controls underwent magnetic resonance imaging of the thigh, muscle strength and endurance, and exercise tolerance assessments. RESULTS:: Thigh mass distribution was bimodal (cutoff 19.0 kg m). Six COPD patients (16 +/- 2.5 kg m) (P < 0.05) presented reduced thigh mass (COPDLQ), whereas 10 patients with normal quadriceps mass (COPDNQ) and all controls had identical mass distribution (22 +/- 2.4 kg m). COPDLQ patients had lower muscle function and lower exercise tolerance than both COPDNQ and controls (P < 0.05 each), but muscle strength corrected by mass was similar between COPD patients (COPDLQ 0.59 +/- 0.12 and COPDNQ 0.55 +/- 0.10 Nm kg m) and controls (0.62 +/- 0.04 Nm Kg m). In contrast, endurance to muscle mass ratio was lower in COPD (COPDLQ and COPDNQ 0.91 +/- 0.15 and 0.89 +/- 0.15 J kg m) than in controls (1.07 +/- 0.11 J kg m) (P < 0.05). Half-time phosphocreatine recovery (COPDLQ 66 +/- 14 and COPDNQ 55 +/- 9 secs, not significant) was also slower than in controls (43 +/- 10 secs) (P < 0.01). CONCLUSIONS:: Impaired muscle strength was explained by reduced muscle mass, but it did not account for abnormal muscle endurance. The latter seems associated to impaired O2 transport/O2 utilization, resulting in altered muscle bioenergetics.