What is the minimum daily duration of supplemental oxygen therapy you recommend to patients with chronic hypoxic respiratory failure?

I think the REDOX trial has changed the landscape of long-term oxygen therapy, and I would now advise most patients to use oxygen a minimum of 15 hours/day. In patients with particularly severe hypoxemia, e.g., patients whose PO2 on room air is in the 30's, I would advise them to use oxygen for as c...