long term oxygen therapy (LTOT)

Last edited 02/2021 and last reviewed 05/2021

Long-Term Oxygen Therapy (LTOT)

LTOT can be defined as oxygen used for at least 15h per day in chronically hypoxaemic patients

• chronic hypoxaemia is defined as a PaO2 <=7.3kPa or, in certain clinical situations, PaO2 <=8.0kPa (1,2)

LTOT is delivered via an oxygen concentrator and should be differentiated from the use of oxygen as a palliative measure for symptomatic relief in breathless patients

LTOT

• oxygen flow rate must be sufficient to raise the waking oxygen tension above 8kPa, (60 mmHg)
• LTOT is usually given for at least 15 hours daily, to include night time, in view of the presence of worsening arterial hypoxaemia during sleep
• LTOT is likely to be life long

Long-term oxygen therapy in patients with chronic obstructive pulmonary disease

• Patients with stable chronic obstructive pulmonary disease (COPD) and a resting PaO2 <=7.3kPa should be assessed for long-term oxygen therapy (LTOT) which offers survival benefit and improves pulmonary haemodynamics

• LTOT should be ordered for patients with stable COPD with a resting PaO2 <=8kPa with evidence of peripheral oedema, polycythaemia (haematocrit >=55%) or pulmonary hypertension

• LTOT should be ordered for patients with resting hypercapnia if they fulfil all other criteria for LTOT

LTOT in other respiratory or cardiac disease

• LTOT should be ordered for patients with interstitial lung disease (ILD) with a resting PaO2 <=7.3kPa

• LTOT should be ordered for patients with ILD with a resting PaO2 <=8kPa in the presence of peripheral oedema, polycythaemia (haematocrit >=55%) or evidence of pulmonary hypertension

LTOT in patients with cystic fibrosis

• LTOT should be ordered for patients with cystic fibrosis (CF) with a resting PaO2 <=7.3kPa

• LTOT should be ordered for patients with CF with a resting PaO2 <=8kPa in the presence of peripheral oedema, polycythaemia (haematocrit >=55%) or evidence of pulmonary hypertension

LTOT in patients with pulmonary hypertension

• LTOT should be ordered for patients with pulmonary hypertension, including idiopathic pulmonary hypertension, when the PaO2 is <=8kPa

LTOT in patients with neuromuscular or chest wall disorders

• Non-invasive ventilation (NIV) should be the treatment of choice for patients with chest wall or neuromuscular disease causing type 2 respiratory failure. Additional LTOT may be required in case of hypoxaemia not corrected with NIV

LTOT in patients with advanced cardiac failure

• LTOT should be ordered for patients with advanced cardiac failure with a resting PaO2 <=7.3kPa

• LTOT should be ordered for patients with advanced cardiac failure with a resting PaO2 <=8kPa in the presence of peripheral oedema, polycythaemia (haematocrit >=55%) or evidence of pulmonary hypertension on ECG or echocardiograph

Notes:

• smoking and home oxygen (1)
  • smoking cessation techniques should be continued prior to any home oxygen assessment and prescription. Patients should be made aware of the dangers of continuing to smoke in the presence of home oxygen therapy

Reference:

1. British Thoracic Society (January 2006). Report on Clinical Component for the Home Oxygen Service in England and Wales.
2. Hardinge M, Annandale J, Bourne S, et al.British Thoracic Society guidelines for home oxygen use in adults.Thorax2015;70:i1-i43.