THE EFFICIENCY OF VENTILATION DURING VOLUNTARY HYPERPNEA: STUDIES IN NORMAL SUBJECTS AND IN DYSPNEIC PATIENTS WITH EITHER CHRONIC PULMONARY EMPHYSEMA OR OBESITY *

Abstract

Concomitant measurements of the energy cost of breathing and the mechanical work performed on the lungs were used to calculate the efficiency of the chest wall and diaphragm. Seven normal subjects had values below 7%. Six patients with emphysema had comparable values at similar work loads, while 5 obese patients had lower efficiencies. The low values observed in the latter group were attributable to a high energy expenditure. The extra energy was presumably used to move the adipose tissues overlying the chest and abdominal walls.