Long-term oxygen therapy may improve skeletal muscle metabolism in advanced chronic obstructive pulmonary disease...

Skeletal muscle metabolite depletion exists in advanced chronic obstructive pulmonary disease (COPD) patients with chronic hypoxaemia. The purpose of this study was to investigate if long-term oxygen therapy (LTOT) can improve skeletal muscle energy metabolism. Eight patients with advanced COPD, four with chronic hypoxaemia, were investigated using muscle biopsy specimens from the quadriceps femoris muscle applying the needle biopsy technique. The investigation was performed twice, before and after approximately 8 months of LTOT in the hypoxaemic patients. Eight healthy controls of similar age were also investigated. In the COPD patients, muscle glycogen, ATP and creatine phosphate (CrP) concentrations, were 42% (P < 0.01), 18% (P < 0.05) and 21% (P = n.s.) lower than in the healthy controls, respectively, while creatine (Cr) and lactate concentrations were 21% and 90% higher, respectively in the COPD patients compared to the healthy control subjects (P < 0.05). After LTOT, the 'energy index' CrP/(CrP + Cr) ratio increased by 0.12 in the LTOT patients but decreased by 0.12 in the control COPD patients (P < 0.05). The results indicate an improvement in skeletal muscle energy metabolism during LTOT in COPD patients with chronic hypoxaemia.