Feedback-controlled negative pressure ventilation in patients with stable severe hypercapnic chronic obstructive pulmonary disease

Background: In recent studies, the efficacy of intermittent rest of the ins piratory muscles as an option of treating patients with severe chronic obst ructive pulmonary disease (COPD) has become questionable. Objective: The ai m of our study was to analyze the effects of feedback-controlled intermitte nt negative pressure ventilation (INPV) on stable, but severely hypercapnic COPD patients. Methods: 21 clinically stable, hypercapnic patients with se vere CORD underwent INPV with chest shells for 3 weeks, 6 h a day. The INPV sessions were optimized by a visual biofeedback system, which enabled cont rol over the decrease in diaphragmatic activity. Respiratory muscle (RM) fu nction parameters, lung function parameters, blood gases and exercise capac ity were analyzed. Results: In the end, 19 patients concluded INPV treatmen t. They had PaO2 of 56.5 +/- 11.8 mm Hg, PaCO2 of 50.2 +/- 2.7 mm Hg (mean +/- SD) and FEV1 of 27.8 +/- 4.3% predicted before treatment. There was no statistically significant change in lung function parameters, RM function p arameters, physical performance and level of dyspnea after 3 weeks of INPV. Conclusion: We conclude that intermittent RM rest induced by INPV can rela x inspiratory muscles in most patients with stable severe COPD, but fails t o improve RM function and exercise capacity. Copyright (C) 2000 S. Karger A G, Basel.