The European respiratory journal : official journal of the European Society for Clinical Respiratory Physiology
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Randomized Controlled Trial Clinical Trial
Effects of noninvasive ventilation on lung hyperinflation in stable hypercapnic COPD.
Two previous uncontrolled studies have suggested that noninvasive mechanical ventilation (NIMV) in patients with hypercapnic chronic obstructive pulmonary disease (COPD) improves arterial blood gas tensions by decreasing lung hyperinflation with the consequent reduction in inspiratory loads and changes in ventilatory pattern. The aim of this randomised placebo-controlled study was to determine whether these mechanisms play a pivotal role in the effects of NIMV on arterial blood gases. Thirty-six stable hypercapnic COPD patients were randomly allocated to NIMV or sham NIMV. ⋯ All of the above changes were significant compared with sham NIMV. Changes in Pa,CO2 were significantly related to changes in dynamic intrinsic positive end-expiratory pressure, inspiratory lung impedance, VT and FRC. It was concluded that the beneficial effects of noninvasive mechanical ventilation could be explained by a reduction in lung hyperinflation and inspiratory loads.