[Early use of noninvasive positive pressure ventilation for patients with acute exacerbations of chronic obstructive pulmonary disease: a multicentre randomized controlled trial].

OBJECTIVE: To assess the efficacy and safety of noninvasive positive pressure ventilation (NPPV) for acute exacerbations of chronic obstructive pulmonary disease (AECOPD) patients on general wards.

METHODS: A prospective multicentre randomized controlled trial was conducted in 19 hospitals in China over 16 months. 342 AECOPD patients with pH > or = 7.25 and arterial partial pressure of carbon dioxide (PaCO(2)) > 45 mm Hg (1 mm Hg = 0.133 kPa) were recruited on general wards and randomly assigned to standard medical treatment (group A, n = 171) or early administration of NPPV plus standard medical treatment (group B, n = 171).

RESULTS: The characteristics of the two groups on admission were similar. The number of AECOPD patients requiring intubations in group B was significantly less than that of the group A (8/171, 26/71, P = 0.002). Subgroup analysis showed the need for intubation in both the mild (pH > or = 7.35) and the severe (pH < 7.30) acidotic patients in group B were decreased (9/80, 2/71, P = 0.047 and 8/30, 3/43, P = 0.048 respectively). The mortality in hospital was reduced slightly by NPPV but with no significant difference (7/171, 12/171, P = 0.345). Respiratory rate (RR), scale for accessory muscle use and arterial pH improved rapidly at the first 2 hours only in patients of group B. After 24 hours, the differences of pH, arterial partial pressure of oxygen (PaO(2)), scale for accessory muscle use and RR in group B [7.36 +/- 0.06, (72 +/- 22) mm Hg, 2.5 +/- 0.9, (22 +/- 4)/min] were statistically significant compared with group A [7.37 +/- 0.05, (85 +/- 34) mm Hg, 2.3 +/- 1.1, (21 +/- 4)/min, P < 0.01 for all comparisons].

CONCLUSIONS: The early use of NPPV on general wards improves arterial blood gas and respiratory pattern, decreases the rate of need for intubation in AECOPD patients. NPPV is indicative for alleviating respiratory muscle fatigue and preventing respiratory failure from exacerbation.