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Oxygen therapy

Supplemental oxygen is recommended for those with low oxygen levels in respiratory failure at rest (a partial pressure of oxygen less than 50–55 mmHg or oxygen saturations of less than 88%). When taking into account complications including cor pulmonale and pulmonary hypertension, the levels involved are 56–59 mmHg. Oxygen therapy is to be used for between 15 and 18 hours per day and is said to decrease the risk of heart failure and death. In those with normal or mildly low oxygen levels, oxygen supplementation (ambulatory) may improve shortness of breath when given during exercise, but may not improve breathlessness during normal daily activities or affect the quality of life. During acute exacerbations, many require oxygen therapy; the use of high concentrations of oxygen without taking into account a person's oxygen saturations may lead to increased levels of carbon dioxide and worsened outcomes. In those at high risk of high carbon dioxide levels, oxygen saturations of 88–92% are recommended, while for those without this risk, recommended levels are 94–98%. Once prescribed long-term oxygen therapy, patients should be re-assessed after 60 to 90 days, to determine whether supplemental oxygen is still indicated and if prescribed supplemental oxygen is effective.