Short-term effects of expiration under positive pressure in patients with acute exacerbation of chronic obstructive pulmonary disease and mild acidosis requiring non-invasive positive pressure ventilation

Objective: To investigate the feasibility and the efficacy of expiration under positive pressure (PEP mask) as a chest physiotherapy in patients with exacerbation of chronic obstructive pulmonary disease (COPD) and acute hypercapnic respiratory failure (AHRF) requiring non-invasive positive pressure ventilation (NIPPV). Design: A prospective, randomised, controlled study. Setting: A respiratory intensive care unit. Patients and interventions: Twenty-seven patients with large amounts of bronchial secretions on clinical examination due to exacerbation of COPD and mild acidosis were randomly divided into two Groups. Group A (13 patients) received PEP mask plus assisted coughing. The controls (group B, 14 patients) received assisted coughing alone. Outcome measures: The primary end point was to compare total sputum wet weight and to assess the feasibility of the PEP mask. Secondary outcomes were: (a) the time required for weaning patients from NIPPV, (b) treatment failure expressed as mortality within 2 months after discharge from the respiratory intensive care unit (RICU) or the need for endotracheal intubation (ETI). Results: The amount of sputum production at the end of physiotherapy was significantly (p<0.01) higher in group A (9.6+/-3.9 g) compared with group B (4.7+/-2.5 g). The total length of weaning time was significantly lower in group A (4.9+/-0.8 days) versus group B (7.0+/-0.7 days), p<0.01. Mortality and ETI were not significantly different in the two groups of patients (0 versus I and 0 versus 1, respectively). Conclusions: Expiration under positive pressure was effective in acutely removing secretions in patients with exacerbation of COPD and mild acidosis requiring NIPPV. In conclusion, we suggest that this chest physiotherapy technique represents a useful therapeutic option for such patients and it should often be performed in addition to NIPPV.