Patients with COPD: Indications for long-term oxygen therapy

Test your medicine knowledge with the MKSAP challenge, in partnership with the American College of Physicians.

A 72-year-old woman is evaluated during a routine examination. She has very severe COPD with multiple exacerbations. She has dyspnea at all times with decreased exercise capacity. She does not have cough or any change in baseline sputum production. She is adherent to her medication regimen, and she completed pulmonary rehabilitation 1 year ago. She quit smoking 1 year ago. Her medications are a budesonide/formoterol inhaler, tiotropium, and an albuterol inhaler as needed.

On physical examination, pulse rate is 94/min, and respiration rate is 26/min. Pulmonary examination reveals distant breath sounds and no wheezing. Oxygen saturation is 86% breathing ambient air. Pulmonary function testing reveals an FEV1 of 26% of predicted and an FEV1/FVC ratio of 41%.

Which of the following is the most appropriate next step in management?

A: Oral antibiotics
B: Oxygen therapy
C: Prednisone taper
D: Repeat pulmonary rehabilitation

MKSAP Answer and Critique

The correct answer is B: Oxygen therapy.

The most appropriate next step in management is long-term oxygen therapy (LTOT). This patient’s oxygen saturation is 86% breathing ambient air. Indications for LTOT are an arterial PO2 of less than or equal to 55 mm Hg (7.3 kPa) or an oxygen saturation of less than or equal to 88% when breathing ambient air. In patients who qualify for continuous therapy because of resting hypoxemia, duration of oxygen treatment should be greater than 15 hours per day and preferably longer. The use of long-term oxygen therapy in patients with chronic respiratory failure improves survival and has a beneficial effect on hemodynamics, hematologic characteristics, exercise capacity, mental status, general alertness, motor speed, and hand grip.

Studies have shown that delivering oxygen during exercise can increase the duration of endurance and/or reduce the intensity of breathlessness at the end of exercise. The Nocturnal Oxygen Therapy Trial (NOTT) showed that continuous supplemental oxygen therapy is better than nocturnal oxygen therapy alone in enhancing survival. The role and effectiveness of supplemental oxygen are less clear in patients with pulmonary disease who have normal oxygenation at rest and desaturation with exertion or nocturnally.

There is no indication for antibiotics or prednisone because this patient has no evidence of an acute exacerbation or bronchospasm.

This patient may benefit from undergoing pulmonary rehabilitation again, because data show that repeating pulmonary rehabilitation has benefits. However, given her resting hypoxemia, the most appropriate next step in management is LTOT.

Key Point

In patients with COPD, indications for long-term oxygen therapy are an arterial PO2 of less than or equal to 55 mm Hg (7.3 kPa) or an oxygen saturation of less than or equal to 88%.

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