Design of body plethysmograph for use in field studies.

Abstract

A mobile laboratory was developed for field studies of airways resistance in man. A body plethysmograph was mounted in a caravan, 22 x 8 ft, which also contained a smoking compartment used in studies on the acute response to cigarettes. The caravan was an excellent laboratory despite a little trouble with vibration, temperature control in summer, and instability of air pressure in windy weather, accentuated by the small internal volume. The plethysmograph was designed for simplicity in operation and servicing in the field. Measurements could be made with only two controls and a comprehensive list of easily replaceable spares was carried. All data were transcribed for computer analysis. A quick approximate method of estimating airway resistance and resistance changes was developed for immediate assessment of the results.