Water vapor pressure of end-tidal air of normals and chronic bronchitics.

Abstract

The water vapor pressure of the end-tidal gas of normals and patients with chronic obstructive airways disease was measured under situations likely to occur in respiratory physiological measurements. A mean value of 37.8 mm Hg was found at the lips in normals and 37.5 mm Hg when the subjects breathe through a valve box. The mean pressure deep inside the oral cavities was 41.9 mm Hg. The results in the patients were 2-3 mm Hg lower.