Am. J. Respir. Crit. Care Med., Vol 155, No. 3, Mar 1997, 893-898.
Comparison of three oxygen delivery systems during exercise in hypoxemic patients with chronic obstructive pulmonary disease
EM Hagarty, MS Skorodin, WE Langbein, CI Hultman, JA Jessen and KC Maki
Edward Hines Jr. Hospital, Department of Veterans Affairs, Hines, Illinois 60141, USA.
Oxygen therapy improves submaximal exercise tolerance in hypoxemic patients
with chronic obstructive pulmonary disease (COPD). This study compared the
standard nasal cannula, reservoir nasal cannula, and a demand flow device
in 15 male hypoxemic patients with COPD. On six separate occasions each
subject used, in a randomized order, all three systems while completing
incremental cycle ergometry and a test circuit composed of tasks that
simulate activities of daily living. Oxygen flow required during exercise
was 1.8 +/- 0.9 and 2.8 +/- 0.7 L/min for reservoir nasal cannula and
standard nasal cannula use, respectively (p < 0.0001). The effect of the
three oxygen delivery systems on oxygen saturation (Spo2) during the last
30 s of exercise varied with type of activity. Only during demand flow
device use while undressing and dressing was the subjects' Spo2 (90 +/- 3%)
significantly lower (p = 0.019). There was a trend toward lower Spo2 with
the demand flow device (p = 0.103) during arm work above shoulder level.
Although not statistically significant, reservoir nasal cannula use
resulted in consistently lower tidal volume and minute ventilation during
test circuit activities. Exercise tolerance was not significantly different
between the three oxygen delivery systems.
