Fig. 1From: Impact of corticosteroids on the duration of ventilatory support during severe acute exacerbations of chronic obstructive pulmonary disease in patients in the intensive care unit: a study protocol for a multicentre, randomized, placebo-controlled, double-blind trialStudy design. COPD: chronic obstructive pulmonary disease; ICU: intensive care unit; VFD-28: ventilator-free days and alive at day 28Back to article page