Long-Term Oxygen Therapy in COPD: evidences and open questions of current indications

Long term oxygen therapy (LTOT) has been shown to improve the survival rate in Chronic Obstructive Pulmonary Disease (COPD) patients with severe resting hypoxemia by NOTT and MRC studies, published more than 25 years ago. The improved survival was found in patients who received oxygen for more than 15 hours/day. The effectiveness of LTOT has been documented only in stable COPD patients with severe chronic hypoxemia at rest (PaO255%. In fact no evidence supports the use of LTOT in COPD patients with moderate hypoxemia (55<PaO2<65 mmHg), and in those with decreased oxygen saturation (SO2