Effect of pressure support on end-expiratory lung volume and lung diffusion for carbon monoxide.

Objectives: The level of pressure-support ventilation can affect mean airway pressure and potentially lung volume, but its increase is usually associated with a reduced respiratory rate, and the net effects on the gas exchange process and its components, including end-expiratory lung volume, have not been carefully studied. We measured pulmonary conductance for gas exchange based on lung diffusion for carbon monoxide in patients receiving pressure-support ventilation.

Design: Prospective, randomized, crossover study.

Shortened telomeres in circulating leukocytes of patients with chronic obstructive pulmonary disease.

Rationale: Telomere length is considered a marker for biological aging. Chronic obstructive pulmonary disease (COPD) may be associated with premature aging.

Objectives: To test the hypothesis that patients with COPD experience accelerated telomere shortening and that inflammation is linked to this process.