What is Long-term oxygen therapy - Meaning and definition

Published by Roberto Wenk. Reviewed by Alison Ramsey. Last updated date: January 8, 2019.

Long-term oxygen therapy (LTOT) improves survival, exercise, sleep, and cognition in patients with chronic obstructive pulmonary disease (COPD).

Oxygen sources include gas, liquid, and concentrator.
Oxygen delivery methods include nasal continuous flow, pulse demand, reservoir cannulas, and transtracheal catheter.

Physiological indications for oxygen include an arterial oxygen tension (PaO2) < 55 mm Hg. The therapeutic goal is to maintain arterial oxygen saturation (SpO2) > 90% during rest, sleep, and exertion.

Home oxygen therapy
Patients with COPD, whose disease is stable on a full medical regimen, with PaO2 < 55 mm Hg (corresponding to an SaO2 < 88 %), should receive LTOT.
A patient whose PaO2 is 55 to 59 mm Hg (SaO2 89%) and who exhibits signs of tissue hypoxia, such as pulmonary hypertension, cor pulmonale, erythrocytosis, edema from right heart failure, or impaired mental status, should also receive LTOT.
Desaturation only during exercise or sleep suggests consideration of oxygen therapy specifically under those conditions.

Some grey areas remain, such as patients with adequate PaO2 who have severe dyspnea relieved by low-flow oxygen or patients who are limited in their exertion capacity but improve their exercise performance with supplemental oxygen.

American Thoracic Society (ATS) and European Respiratory Society (ERS) 2004. Standards for the diagnosis and management of patients with COPD. Internet. Accessed on January 16, 2011.

Published by Roberto Wenk. Last updated date: July 7, 2016.

Patients with severe COPD commence oxygen therapy at home many years before the disease reaches the terminal phase.
Long term oxygen therapy extends life expectancy in hypoxemic COPD patients if given for 12-15 hours a day – five-year survival in 41% of patients.

Indications:
• Non smoking patient with stable, severe COPD – FEV1 < 1.5L and arterial hypoxemia - <7.3 Kpa (55 mmHg)
• COPD patients with clinically stable PaO2 between 7.3 and 8 KPa ( 55-60 mmHg), associated with polycythemia, nocturnal hypoxia, peripheral edema, or evidence of pulmonary hypertension

LTOT is not recommended for patients with PaO2 > 8 KPa
Oxygen concentrator is cheap and more convenient than cylinders
Ambulatory oxygen therapy uses lightweight oxygen cylinders and is used in patients who are ambulant and have the need to move about and leave home. Those who smoke cigarettes should not be prescribed ambulatory oxygen as there is a considerable risk from burns.
Mode of administration: nasal cannula
Rate of flow: 1-3 L/min usually achieves a saturation of > 90%; the rate is increased by 1L at night and during exercise to prevent desaturation.

Leach RM. Palliative Care in Non-Malignant, End-Stage Respiratory Disease. Hanks G, Cherny NI, Christakis NA, Fallon M, Kaasa S, Portenoy RK (Ed).Oxford Textbook of Palliative Medicine. Oxford University Press, Fourth Edition, 2010, pp. 1231-1256.

Long-term oxygen therapy

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