Regional Lung Mechanics in Pulmonary Disease*

Abstract

The compliance of the upper and lower lobe as well as the differences in intrathoracic pressure have been measured. In the normal lung of man there is no significant difference between the upper and the lower lobe in static compliance. Greater pressure swings occur about the lower lobe than about the upper lobe, which in turn has greater pressure swings than those about an esophageal pressure tap. These pressure differences increase with lung volume. In patients who are older, with and without mild obstructive airway disease, the whole lung compliance, and particularly upper lobe compliance, is greater than in normal subjects. Patients with moderate to severe obstructive airway disease have more compliant lungs than normal subjects, and upper lobe compliance is significantly greater than lower lobe compliance. Homogeneous intrathoracic pressures are found in those patients with obstructive disease at all lung volumes. Patients with pulmonary fibrosis, although older, had a lobar compliance similar to that in younger normal subjects, and intrathoracic pressure differences were similar to those in the normal patients. In the presence of obstructive airway disease the lung or lobe with pulmonary fibrosis may have normal compliance, but it has homogeneous intrathoracic pressures. In pleural disease, differences exist in intrathoracic pressure between aU points measured in the chest.