Noninvasive positive pressure mechanical ventilation (NIPPV) in exacerbated chronic obstructive pulmonary disease (COPD) has been investigated early and after 1 yr of follow-up. To this end, 30 patients were enrolled in a prospective, controlled trial: 15 had early administration of NIPPV (Group A), 15 had medical therapy only (Group B); assignment was made on the basis of equipment availability only. In-hospital mortality, need for endotracheal intubation and mean length of hospitalization were lower in Group A, though the difference was not statistically significant. Arterial oxygen tension in arterial blood (Pa,O-2), carbon dioxide tension in arterial blood (Pa,CO2) and HCO3- improved significantly in both groups from admission to discharge: 45.8+/-8.6 versus 64.9+/-10.0; 59.4+/-11.8 versus 48.6+/-7.3; 34.3+/-4.3 versus 30.1+/-3.4 in group A; 49.2+/-11.4 versus 60.9+/-8.2; 52.6+/-15.9 versus 44.4+/-8.7; 31.7+/-5.9 versus 28.0+/-3.6 in group B, respectively, p<0.05 for all comparisons; pH, percentage forced expiratory volume in one second (FEV1) and tidal volume (VT) improved significantly in patients of group A only: 7.36+/-0.04 versus 7.41+/-0.02; 39.8+/-13.6 versus 49.4+/-11.7; 0.71+/-0.3 versus 0.84+/-0.4, respectively, p<0.05. During follow-up, 3, 6, and 12 months survival rates were significantly higher in Group A than in Group B (p<0.02). Hospital new admissions over 1 yr were more frequent in Group B (n=6, incidence rate: 0.216%) than in Group A (n=4, incidence rate: 0.084%). Therefore, noninvasive positive pressure mechanical ventilation may be added to "conventional" medical therapy in exacerbated chronic obstructive pulmonary disease.