Abstract
We examined the history-dependent changes in the end expiratory position in 12 healthy subjects. The subjects lay on a bed in a supine position and held a mouthpiece in their mouth. The subject inspired deeply and the mouthpiece shutter was closed at the end of inspiration. The subject inspired with more effort for a further 3 to 4 s using abdominal breathing while the airway was closed. There was a slight but non-significant increase in the end expiratory position of each of the five breaths taken after weak forced inspiration using the diaphragm. However, strong forced inspiration caused a highly significant rise in the mean value of the end expiratory position of the five post maneuver breaths (p<0.01) . These results indicate that the diaphragm contributes to the history-dependent changes in the end expiratory abdominal position.
