Key learning points

  • The Irish Thoracic Society recommends long-term oxygen therapy in adults with chronic hypoxaemia
  • Patients with resting oxygen saturations above 92% are unlikely to require long-term oxygen therapy
  • A home oxygen order form (HOOF) should be used when ordering temporary home oxygen


The Irish Thoracic Society (ITS) guidelines for long-term oxygen therapy (LTOT) in adults recommend that oxygen therapy is used by patients with proven hypoxaemia for at least 15 hours per day.1 Long-term oxygen therapy (LTOT) is prescribed to improve survival in patients with hypoxia. LTOT is a treatment for hypoxia but not for breathlessness,2 yet many people with breathlessness are unnecessarily prescribed oxygen and will not benefit. Patients with resting saturations above 92% are unlikely to require LTOT.1

Risks of LTOT

Oxygen as a therapy has some risks. There is the danger of the ‘carbon dioxide retainer’ in chronic obstructive pulmonary disease (COPD). For such patients, too little carbon dioxide is removed from the blood by the lungs, leading to increased levels of CO2 in the blood (hypercapnia).3 There is an increased risk of hypercapnia in patients with COPD taking oxygen.3

Other situations in which oxygen therapy has risks include myocardial infarction, in which oxygen administration can lead to dangerous undesirable circulatory changes and increased myocardial ischaemia.4,5 In addition, there is a reported increase in mortality among ventilated stroke patients with higher blood oxygen levels, leading to suggestions that unnecessary oxygen administration should be avoided in stroke patients.6

It is also worth thinking about patients who travel regularly because air travel reduces resting saturations due to pressurised cabins.7 The ITS recommend a pre-flight assessment involving a clinical history and examination to identify risk of flying and need for in-flight oxygen.1 A hypoxic challenge test should be conducted within this assessment, with an arterial oxygen tension of <6.6kPa (<50mmHg) or an oxygen saturation of less than 85% indicating the need for in-flight oxygen.7

Of course, if assessment indicates that the person requires oxygen for travel, it may increase their insurance payments and they will need to arrange oxygen for overseas.

Oxygen forms 

Temporary oxygen is ordered on a home oxygen order form (HOOF) form.1 This form is for non-specialist healthcare professionals or for temporary supply pending specialist review. The HOOF is used to order a static concentrator or cylinder for use in the home, and flow rate and either a mask or a nasal cannula should be specified. This is then sent to the oxygen provider.

Consent needs to be obtained from the patient on a home oxygen consent form, which allows data sharing. This is stored with the patient’s records, together with a risk assessment on an initial home oxygen risk mitigation form.

The initial home oxygen risk mitigation form ensures that the patient and/or carer understands the safety advice regarding the use of home oxygen, including the dangers of smoking cigarettes and e-cigarettes, naked flames, the use of paraffin-based ointments and pressure-relieving mattresses. They are then referred to the oxygen assessment team.

For information on the evidence for LTOT see the article by Jane Scullion on The evidence for long-term oxygen therapy

Jane Scullion, respiratory nurse consultant, University Hospitals of Leicester, and a respiratory clinical lead within the East Midlands working with the Clinical Senate

This project was initiated and funded by Teva Respiratory. Teva have had no influence over content. Topics and content have been selected and written by independent experts.