EFFECTS OF THE COMPRESSIBILITY OF ALVEOLAR GAS ON THE DYNAMICS AND WORK OF BREATHING,
Abstract
Alveolar gas is compressed and expanded during every breathing cycle. The volume displacement measured at the mouth Vt (tidal volume) is therefore smaller than the volume displacement of the lung Vt that may be measured with a body plethysmograph. Experimental data found in normal subjects and in patients with obstructive emphysema confirm the theory that the ratio Vt/Vt decreases with increasing airway resistance, frequency, and lung volume. There was little effect in normal subjects breathing at different breathing rates; however, in patients with obstructive emphysema it may be appreciable. With increasing altitude the effect is expected to be more pronounced. The mechanical work performed in compressing and expanding alveolar gas may be determined by recording the volume displacement of the lung simultaneously with tidal volume and intraesophageal pressure. Normally, work related to compressibility is insignificant, but in patients with obstructive emphysema, it becomes appreciable during hyperpnea. The compressibility of alveolar gas was also found to increase the negative work performed by respiratory muscles. (Author)
Document Details
- Document Type
- Technical Report
- Publication Date
- Oct 01, 1963
- Accession Number
- AD0437863
Entities
People
- A. B. Otis
- M. J. Jaeger
Organizations
- University of Florida