[Effects of nurse home visits on compliance to long-term oxygen therapy. 14 months follow-up]

Long-term oxygen therapy (LTOT) is the only treatment improving survival of patients with respiratory failure due to chronic obstructive pulmonary disease (COPD). Benefits of treatment depend mainly on daily duration of oxygen use. The aim of the study was to assess daily use of oxygen and to evaluate influencing factors.

Consecutive patients qualified to LTOT were included. Eligibility for LTOT was based on the ATS//ERS guidelines. All patients were instructed to use oxygen from oxygen concentrator for 15 hours per day or more. Duration of oxygen therapy was verified every 4 weeks by visiting respiratory nurse using counter clock of oxygen concentrator. The nurses were also encouraging patients to breathe oxygen for at least 15 h/d.

Study group consisted of 30 patients (77% with COPD) aged 67+/-9 yrs, mean FEV, 46+/-18% pred., RV%TLC 64+/-16%, PaO2 50+/-6 mm Hg. Mean duration of oxygen therapy for the group was 12.5+/-4.6 h/d. Eleven (37%) subjects followed prescription during whole follow-up period (mean oxygen use 17.4+/-2.6 h/d). Mean oxygen use in the non-compliant group was 9.6+/-2.7 h/d. In COPD group compliant patients had significantly lower TLC (100+/-19% pred. v. 152+/-36% pred., p=0.001) and lower PaCO2 (38+/-6 mm Hg v. 47+/-8 mm Hg, p<0.05) when compared to the non-compliant group. During the first month of treatment 48% of patients were compliant. From the second month onward percentage of compliant patients fell to 30% and remained stable to the end of the study. Fourteen patients (47% complained of electricity consumption and 7 patients (23%) complained of the noise of working concentrator. Daily oxygen use in the latest group was significantly lower when compared to those who did not complain of the noise (9+/-3.7 h/d v. 13.5+/-4.4 h/d; p=0.02).

The best compliance to home oxygen therapy is observed at the beginning of treatment. Frequent home nurse visits do not improve compliance. We hypothesize that the use of other oxygen sources eg. liquid oxygen, that are silent and do not increase the cost of electricity, could improve compliance.