Postural relief of dyspnea in severe chronic obstructive pulmonary disease.

Abstract

The effect of body position change was studied in 17 patients with severe disabling chronic obstructive pulmonary disease. Multiple respiratory muscle electromyograms, gastric, esophageal, and transdiaphragmatic pressures, and thoracoabdominal diameters (by magnetometer) were measured in the supine, standing, erect seated, and forward leaning (seated) positions during quiet breathing. Seven patients showed striking relief of dyspnea in the leaning forward position, and 3 of these obtained relief upon lying supine as well. All 7 showed paradoxical (inward) inspiratory motion of the abdomen in standing and erect seated postures, which was corrected by assuming the supine and forward leaning positions. When compared to the remaining 10 patients, these 7 had significantly greater TLC (P < 0.01), FRC (P < 0.05), and RV (P < 0.02), although FVC and FEV1/FVC values were not significantly different. Their accessory inspiratory muscle EMG activity was augmented to a significantly greater degree on assuming the sta...