Effects of F(I)O2 on leg VO2 during cycle ergometry in sedentary subjects.

In a recent study of completely sedentary normal young subjects, leg VO2max was reduced by hypoxia in proportion to mean capillary PO2 as F(I)O2 was reduced from 0.15 to 0.12.

Ventilation-perfusion mismatch in patients with pleural effusion: effects of thoracentesis.

Pleural effusion (PE) often causes abnormal pulmonary gas exchange. Thoracentesis is commonly used to relieve dyspnea in patients with PE, but its effect upon arterial oxygenation is varied and poorly understood. This investigation sought to: (1) characterize the distribution of ventilation-perfusion (VA/Q) ratios in patients with PE and (2) assess the effects of PE drainage by thoracentesis upon pulmonary gas exchange.

Increase in pulmonary ventilation-perfusion inequality with age in healthy individuals.

Arterial oxygen tension (PaO2) is known to decrease with age, and this is accompanied by a number of changes in mechanical properties of the lungs, including loss of elastic recoil and increase in closing volume. The changes in respiratory mechanics with age could induce greater ventilation/perfusion (VA/Q) mismatch and thus explain the decrease in PaO2. In 64 normal subjects aged 18 to 71 yr (lifetime nonsmokers with normal spirometry), we measured VA/Q inequality and arterial respiratory blood gases (PaO2 and PaCO2) at rest in the seated position.