Background: Patients with acute exacerbations of chronic obstructive pulmonary disease may require endotracheal intubation with mechanical ventilation. We designed, and here report on the efficacy of, a noninvasive ventilatory-assistance apparatus to provide inspiratory-pressure support by means of a face mask.
Methods: We assessed the short-term (45-minute) physiologic effects of the apparatus in 11 patients with acute exacerbations of chronic obstructive pulmonary disease and evaluated its therapeutic efficacy in 13 such patients (including 3 of the 11 in the physiologic study) who were treated for several days and compared with 13 matched historical-control patients.
Results: In the physiologic study, after 45 minutes of inspiratory positive airway pressure by face mask, the mean (+/- SD) arterial pH rose from 7.31 +/- 0.08 to 7.38 +/- 0.07 (P less than 0.01), the partial pressure of carbon dioxide fell from 68 +/- 17 mm Hg to 55 +/- 15 mm Hg (P less than 0.01), and the partial pressure of oxygen rose from 52 +/- 12 mm Hg to 69 +/- 16 mm Hg (P less than 0.05). These changes were accompanied by marked reductions in respiratory rate (from 31 +/- 7 to 21 +/- 9 breaths per minute, P less than 0.01). Only 1 of the 13 patients treated with inspiratory positive airway pressure needed tracheal intubation and mechanical ventilation, as compared with 11 of the 13 historical controls (P less than 0.001). Two patients in each group died. As compared with the controls, the treated patients had a more transient need for ventilatory assistance (3 +/- 1 vs. 12 +/- 11 days, P less than 0.01) and a shorter stay in the intensive care unit (7 +/- 3 vs. 19 +/- 13 days, P less than 0.01).
Conclusions: Inspiratory positive airway pressure delivered by a face mask can obviate the need for conventional mechanical ventilation in patients with acute exacerbations of chronic obstructive pulmonary disease.