Fig. 1From: Mental health, serum biomarkers and survival in severe COPD: a pilot studyPatients’ recruitment. Notes: Other exclusion reasons: acute pneumonia confirmed by X-ray; lung resection; thoracic deformations; C-reactive protein (CRP) ≥20 mg/dl; blood pH <7.35; antibiotic therapy within the last 2 weeks. Abbreviations: NIPPV, non-invasive intermittent positive pressure ventilation; LTOT, long-term oxygen therapyBack to article page