1. Quadriceps femoris muscle needle biopsies were performed in 21 patients with chronic obstructive lung disease (COLD) and acute respiratory failure (ARF) and in 21 age-matched healthy control subjects.
2. Muscle samples were analysed to obtain intracellular bicarbonate and pH values from total acid-labile carbon dioxide content. Muscle potassium, magnesium and sodium content were also determined, as well as water compartments.
3. Skeletal muscle of COLD patients with ARF showed intracellular acidosis and reduced potassium and magnesium content. Total muscle water increase was linked to extracellular water increment.
4. It was concluded that in COLD patients with ARF an overall derangement of skeletal muscle metabolism is present.