Blood fuel metabolites at rest and during exercise in patients with advanced chronic obstructive pulmonary disease with and without chronic respiratory failure.

Eighteen patients with advanced chronic obstructive pulmonary disease (COPD), 8 with chronic respiratory failure (CRF group) and 10 without (NCRF group) were investigated using arterial blood analyses before, during and after progressive exercise. Dynamic spirometry was also performed. The arterial blood was analyzed for free fatty acids (FFA), glycerol, 3-hydroxybutyrate, alanine, glucose and lactate concentrations as well as PO2 and PCO2. In the CRF group the concentrations of FFA, glycerol and 3-hydroxybutyrate were lower and the concentrations of glucose and lactate higher than in the NCRF group. Analysis of the whole material revealed that the arterial FFA, glycerol and 3-hydroxybutyrate concentrations correlated positively to arterial PO2 and negatively to arterial PCO2 at rest, as well as during exercise and recovery. The results indicate that lipolysis is decreased in patients with advanced COPD with chronic respiratory failure. An altered glucose metabolism may also exist in these patients.