LONG-TERM OXYGEN-THERAPY - COMPLIANCE WIT H PRESCRIBED OXYGEN FOR AT LEAST 15 HOURS PER DAY

Long-term domiciliary oxygen therapy in patients with chronic respirat ory failure significantly improves both survival and quality of life. These therapeutic objectives are only achieved by daily oxygen therapy of more than 15 hours. For a period of 3 months, we have prospectivel y measured the duration of oxygen therapy in 930 patients with chronic airflow obstruction. This is carried out by reading the meters on the oxygen concentrators, or for liquid oxygen by checking the weight of the cylinders at each delivery, making allowances for the flow rate an d also for natural loss from evaporation. The instructions for oxygen therapy and the true therapy of the patient were then gathered using a questionnaire. The practitioners were questioned on the prescription for oxygen therapy which had been made for each patient, and more gene rally on their usual criteria for prescribing long-term oxygen therapy . The patients (82% male) were aged between 67 +/- 8 years, and were o n domiciliary oxygen therapy 36 +/- 24 months, with hypoxaemia (PaO2 = 56 +/- 9 mmHg), hypercapnoea (PaCO2 = 47 +/- 8 mmHg) and suffering fr om airflow obstruction (FEV1/VC = 42 +/- 14%). The duration of prescri bed oxygen therapy was on average 16 +/- 3 hours. The mean duration of oxygen therapy achieved was 14.5 +/- 5 hours, but only 45% of the pat ients (419/930) managed daily oxygen therapy superior of equal to 15 h ours and were categorised as compliant. Compliant patients were signif icantly more hypoxaemic (PaO2 = 54.5 +/- 9 mmHg, p < 0.01), more hyper capnoeic (PaCO2 = 48 +/- 8 mmHg, p < 0.05), and had more airflow obstr uction (FEV1 over VC = 39.5 +/- 13%, p < 0.01), when compared to the r est of the population. Ceasing smoking, an initial prescription of equ al to or more than 15 hours a day, and supplementary training in oxyge n therapy made either by a nurse or a physiotherapist was equally asso ciated with good compliance. Compliant patients were using their oxyge n in all situations within the house (toilet, meals, and leisure ...), and more willingly than non-compliant patients. We conclude that from the results the prescribing doctor controls the greater part of the f actors leading to the improved therapeutic compliance. The prescriptio n should be made in patients presenting with significant hypoxaemia, t he initial education should be complete and specify each circumstance in the daily life in which oxygen therapy should be used to achieve 15 hours out of the 24. The medical and technical follow-up should reinf orce the initial education to compensate for any aspects which be migh t preventing full compliance.