Oxygen treatment at home

In England and Wales (but not in Scotland) prescriptions for oxygen concentrators have until now been written by the general practitioner, usually after assessment of patients and recommendation by respiratory specialists. Concentrators are then installed in patients' homes by companies that have regional NHS contracts. Patients using oxygen cylinders rather than concentrators receive supplies from local pharmacies after prescription by their general practitioners. From next week (1 February 2006) new arrangements will apply in England and Wales.

There will be three important improvements: all forms of home oxygen treatment will now be provided by a single supplier in each region of England and Wales after receipt of a home oxygen order form specifying the details of usage, such as flow rate and expected hours of use; ambulatory oxygen—including that supplied as liquid—will be generally available for the first time; and specialists based in hospitals will be able to order home oxygen directly. Indeed, respiratory medicine and paediatric teams will probably become the main prescribers of long term oxygen therapy and ambulatory oxygen treatment. General practitioners will still be able to prescribe oxygen, although this will probably be largely for use in emergencies and palliative care.

Long term oxygen treatment for patients with hypoxaemic chronic obstructive pulmonary disease was firmly established 25 years ago by two definitive trials that showed a survival benefit.1^–3 Such treatment was greatly facilitated by the development of oxygen concentrators, which since 1985 have been available on the NHS. Around four fifths of patients using concentrators have chronic obstructive pulmonary disease, and although there is no evidence of survival benefit among patients with other conditions, such as pulmonary fibrosis4 and bronchiectasis, long term oxygen treatment by concentrator is often used if their arterial blood gas concentrations meet the criteria for this treatment.

Most home oxygen is, however, still prescribed in cylinders: approximately 63 000 patients in England and Wales use cylinders and around 33 000 use concentrators. Most patients use oxygen cylinders to deliver short bursts for symptom relief either before or after exercise or, in severe breathlessness, at rest. Lightweight portable systems suitable for use during exercise have not previously been generally available on NHS prescription, even though the potential benefit of ambulatory oxygen was shown 50 years ago.5 Refillable portable containers of liquid oxygen have advantages for some more active hypoxaemic patients but have been little used in the United Kingdom despite being widely available elsewhere in Europe.6

The indications and assessment criteria for long term oxygen therapy remain unchanged.7 But the new arrangements for providing oxygen therapy at home will require more detailed assessment of patients who are thought likely to benefit from such treatment. This is particularly important for patients who are active enough to be potentially suitable for ambulatory oxygen treatment: perhaps around half of the patients currently receiving long term oxygen therapy on the NHS. An uncertain number of patients not meeting the criteria for long term oxygen therapy but showing arterial oxygen desaturation on exercise may also benefit from ambulatory treatment. In general, ambulatory oxygen is indicated for well motivated patients who have oxygen desaturation on exercise and demonstrably better performance when breathing oxygen during exercise. Patients using short bursts of oxygen remain the most difficult to evaluate, however, and more studies on their needs are required.8 Whenever possible, both hypoxaemia and symptomatic benefit from oxygen should be demonstrable before oxygen is prescribed.

Assessing and monitoring patients more often will considerably increase the workload for the NHS. This will require a modest increase in staffing in respiratory medicine departments as well as improved liaison between secondary and community care. The British Thoracic Society's guidelines for assessment indicate that one additional respiratory nurse or other professional is needed per 100 patients receiving long term oxygen therapy.9 The Department of Health anticipates that the change should be “cost neutral,” with the expenditure associated with ambulatory oxygen balanced by savings on inappropriate prescribing. It may prove impossible, however, to remove oxygen from patients whose treatment is established, even if this was prescribed inappropriately. Savings are more likely to come from more judicious assessment of those about to start treatment.

These more streamlined arrangements will be more convenient for patients and should allow many more to benefit from ambulatory oxygen. Given that there will be four suppliers nationally and given the variable performance of different oxygen equipment, it is essential that patients are assessed using the same equipment they will use at home.10 This applies not only to the oxygen source (concentrator, cylinder, or liquid) but also to interfaces (cannulas, masks, etc) and conserving devices (which limit wastage during expiration). Patients will need education and support especially during the period of transition. In particular, patients need to understand that shortness of breath does not necessarily imply shortage of oxygen.

Although considerably fewer children than adults receive home oxygen, they have special requirements for equipment such as flow meters and masks. Children need particularly frequent assessment as they grow, and many will probably need ambulatory oxygen because, even if they are not independently mobile, their parents and carers take them out.

Rationalisation of services for home oxygen treatment should allow patients earlier access to technological developments. Battery operated portable concentrators are already being marketed, and other prospects include concentrators which are able to refill cylinders or to liquefy oxygen for ambulatory use.