CAN LONG-TERM OXYGEN-THERAPY IMPROVE EXERCISE CAPACITY AND PROGNOSIS

The lack of studies as to whether the correction of desaturations during exercise can play a role in improving survival still leaves many problems usually met in the common practice open. (1) Why prescribe long-term oxygen therapy (LTOT) on exercise? Up to now, supplemental oxygen during exercise seems more an approach to the 'dyspnea symptom' than a pivotal component of a comprehensive strategy for long-term management of severe chronic airway obstruction. (2) Who needs LTOT on exercise? It seems reasonable to correct desaturations if this leads to a substantial improvement in exercise tolerance. As to the method of clinical assessment, pulse oximetry can be used for measuring desaturation between rest and exercise, although absolute values are not reliable. (3) How to prescribe LTOT on exercise? In practice, the O2 flow able to prevent desaturation on exercise. restoring an SaO2>90%, is the usual prescription criterion after an appropriate testing able to demonstrate a significant increase in exercise tolerance and conducted comparing the results breathing air with those on O2, the patient being unaware of the inhaled mixture. (4) How to administrate LTOT on exercise? A portable source is usually employed to allow the greatest possible independency. A reservoir nasal cannula can halve the oxygen wastage and is less expensive than a pulse demand valve. In patients needing 24-hour oxygen therapy the transtracheal catheter is being used more and more at present. We need controlled studies on the long-term effects of oxygen on exercise, whereas retrospective studies on survival in patients with exercise desaturations can give short-term contributions to a better comprehension of this subject.