Effects of intermittent positive pressure breathing on emphysematous patients

Abstract

Eight subjects free of pulmonary disease and eighteen with moderate to severe pulmonary emphysema were subjected to 15 minutes of continuous intermittent positive pressure breathing (IPPB) and followed for 2 hours after cessation of therapy. Continuous measurements of ventilation, expiratory gas composition and frequent determinations of arterial blood gases were made. As indicated by improvement of PaCO 2 which persisted throughout the 2 hour recovery period, IPPB was shown to be therapeutically beneficial when properly utilized in patients with moderate to severe pulmonary emphysema. Data are presented which demonstrate that IPPB produces passive hyperventilation and a resultant ventilatory CO 2 loss in patients with moderate disease. In patients with severe disease, slight if any ventilatory loss of CO 2 occurred but improvement in PaCO 2 was shown to be augmented by decreased metabolic CO 2 production related to decreased work of breathing produced by IPPB. Patients in this latter group were found to breathe at an improved level of efficiency following IPPB. The clinical rationale for IPPB therapy in emphysematous patients is presented.