Background: Long-term oxygen therapy (LTOT) is the cornerstone mode of treatment in patients with chronic obstructive pulmonary disease (COPD).
Objectives: The present study aims to investigate the effect of two oxygen sources (concentrator and liquid oxygen) on quality of life, exercise tolerance and compliance to LTOT in patients with COPD.
Methods: The survey included 104 patients with COPD (31 on concentrator treatment and 73 on liquid oxygen). Patients were subjected to pulse oximetry, basic spirometry, measurement of health-related quality of life by the St. George's Hospital respiratory questionnaire instrument and assessment of dyspnoea severity by the modified Borg category scale. Exercise tolerance was evaluated by the S(a)O(2) value after 3 min of walking. S(a)O(2) was measured before and after treatment with each device. Compliance with therapy was defined by the daily duration of oxygen use.
Results: The two LTOT groups did not differ significantly concerning pulmonary function tests (p = 0.49 for FEV(1), 0.98 for FVC, 0.15 for FEV(1)/FVC% and 0.38 for FEF(50%)), S(a)O(2) before (p = 0.28) and after (p = 0.80) O(2) treatment and after the 3-min walking trial (p = 0.47), and St. George's Hospital respiratory questionnaire score (p = 0.45). The liquid oxygen group was less dyspnoeic before treatment (p = 0.02), but this difference disappeared after treatment (p = 0.95). A highly significant difference (p < 0.001) was noted concerning the daily oxygen use. Complete compliance to LTOT (> or =15 h/day) was observed in 12.9 and 42.5%, respectively (p < 0.005). Noise disturbance was noted only in the concentrator group (80%).
Conclusions: We conclude that stationary liquid oxygen seems to be a satisfactory alternative mode for LTOT treatment in COPD patients, with higher patient compliance to therapy in comparison with concentrators.