Distribution pattern of tidal volume in emphysema

ABSTRACT

The relatively contribution of the rib cage and abdomen-diaphragm to tidal volume in emphysematous patients and a control group of healthy individuals was determined during normal tidal inspiration. In the control group the distribution curve was right skewed, whereas it was bimodal in the emphysematous patients. The bimodal shape was attributed to the increased anteroposterior chest diameter and flattened diaphragm which reduced diaphragmatic contribution, and also tot he activity of the accessory muscles of respiration which resulted in a greater contribution to tidal volume by the upper thorax. (AU)