Fig. 2From: High-intensity versus low-intensity noninvasive positive pressure ventilation in patients with acute exacerbation of chronic obstructive pulmonary disease (HAPPEN): study protocol for a multicenter randomized controlled trialSPIRIT schedule of enrollment, intervention, and assessments. APACHE Acute Physiology And Chronic Health Evaluation, NPPV noninvasive positive pressure ventilation, GCS Glasgow coma scale ICU intensive care unitBack to article page