SYMPTOMATIC BENEFIT OF SUPPLEMENTAL OXYGEN IN HYPOXEMIC PATIENTS WITH CHRONIC LUNG-DISEASE

We have compared the symptomatic benefit of air and oxygen at rest in hypoxemic patients with chronic obstructive airway disease (COAD) or interstitial lung disease (ILD). A total of 12 severely disabled patients with COAD (mean +/- SEM, Pa(O2), 50.3 +/- 3.7 mm Hg) and 10 with ILD (Pa(O2), 48.0 +/- 3.1 mm Hg) received 28% oxygen and air by Venturi face mask, each gas on two occasions, in a double-blind randomized fashion. Sa(O2) increased (p < 0.01) in both groups during oxygen breathing: COAD, 85.1 +/- 2.3% versus 93.1 +/- 1.4%; ILD, 85.5 +/- 1.7% versus 94.7 +/- 0.9%. The patients with COAD stated that air helped their breathing on 15 of 24 occasions and that oxygen helped on 22 of 24 occasions (p < 0.05). In the patients with ILD the values were 6 of 20 and 13 of 20 occasions, respectively (p < 0.05). In both groups of patients the severity of breathlessness recorded on a 100-mm visual analog scale was significantly (p < 0.05) lower during oxygen breathing: COAD, 29.6 +/- 4.5 versus 45.6 +/- 6.0; ILD, 30.2 +/- 5.1 versus 48.1 +/- 4.4. Ventilation measured by magnetometers was significantly lower during oxygen breathing in the patients with COAD (8.2 +/- 1.0 versus 9.3 +/- 1.1 L/min; p < 0.05), but the difference between oxygen and air in patients with ILD was not statistically significant (9.3 +/- 1.3 versus 11.2 +/- 1.6 L/min; p > 0.05). We conclude that hypoxemic and breathless patients with COAD or ILD benefit symptomatically at rest from supplemental oxygen and to a greater extent than from air delivered in similar fashion via face mask.