Oxygen for chronic obstructive pulmonary disease

• if PaO2 ≤55 mmHg or SaO2 ≤89% (during rest, exercise, or sleep) to prevent cor pulmonale;
• only Rx proven to ↓ mortality (Annals 1980;93:391; Lancet 1981;i:681);
• no benefit in Pts with moderate hypoxemia (SaO2 89–93%) (NEJM 2016;375:1617) or nocturnal O2 alone (NEJM 2020;383:1129);
• unknown benefit of isolated exertional O2 (AJRCCM 2020;202:121).