Skeletal muscle metabolites and fibre types in patients with advanced chronic obstructive pulmonary disease (COPD), with and without chronic respiratory failure.

Eighteen patients with advanced COPD, 8 with chronic respiratory failure (RF) and 10 without (nonRF, NRF) were investigated using spirometry, arterial blood gas analysis and biopsies taken from the quadriceps femorls muscle. The biopsies were analysed for ATP, creatine phosphate (CrP), creatine (Cr), lactate and glycogen content. Muscle fibre composition was also studied. Low concentrations of ATP, glycogen and CrP were found in the RF patients. Significant correlations were found between muscle metabolites and arterial blood gas values with the strongest correlation between muscle glycogen and arterial PO2 (r = 0.70; p less than 0.001). A very low percentage of "oxidative" type I muscle fibres was found in both groups. Possible mechanisms causing depletion of muscle metabolites are discussed.