COMPARISON OF 3 OXYGEN DELIVERY SYSTEMS DURING EXERCISE IN HYPOXEMIC PATIENTS WITH CHRONIC OBSTRUCTIVE PULMONARY-DISEASE

Oxygen therapy improves submaximal exercise tolerance in hypoxemic pat ients with chronic obstructive pulmonary disease (COPD). This study co mpared the standard nasal cannula, reservoir nasal cannula, and a dema nd flow device in 15 male hypoxemic patients with COPD. On six separat e occasions each subject used, in a randomized order, all three system s while completing incremental cycle ergometry and a test circuit comp osed of tasks that simulate activities of daily living. Oxygen flow re quired during exercise was 1.8 +/- 0.9 and 2.8 +/- 0.7 L/min for reser voir nasal cannula and standard nasal cannula use, respectively (p < 0 .0001). The effect of the three oxygen delivery systems on oxygen satu ration (Spo(2)) during the last 30 s of exercise varied with type of a ctivity. Only during demand flow device use while undressing and dress ing was the subjects' Spo(2) (90 +/- 3%) significantly lower (p = 0.01 9). There was a trend toward lower Spo(2) with the demand flow device (p = 0.103) during arm work above shoulder level. Although not statist ically significant, reservoir nasal cannula use resulted in consistent ly lower tidal volume and minute ventilation during test circuit activ ities. Exercise tolerance was not significantly different between the three oxygen delivery systems.