Patients with COPD have chronic inflammation of the lungs that obstructs the airways. The bronchioles are closed, which reduces the passage of air. As a result, the majority of patients have difficulty in breathing and often have chronic hypoxaemia, which means, low oxygen in the blood. Several studies in the 1980’s demonstrated a higher survival rate in patients with chronic obstructive pulmonary disease (COPD) treated with LTOT.
Treatment with oxygen therapy is recommended in the case of patients with COPD that have an arterial blood oxygen (PaO2) less than 55 mmHg or between 55 and 60 mmHg, which leads to an increase in red blood cells due to blood volume (polycythaemia), heart disease, and heart failure. The studies, therefore, do not support the use of LTOT for patients with a normal level of oxygen in the blood. LTOT must be prescribed by specialised health staff, according to the needs of the patient.
For patients with chronic hypoxaemia (PaO2 ≤ 55 mm Hg), the use of LTOT is recommended for a minimum of 15 to 16 hours a day and the more hours the better, even 24 hours a day, since it is associated with greater survival. In the short-term, the administering of oxygen can improve the hypoxaemia in blood and can also lead to an increase in the physical activity of the patient.
Despite the widely demonstrated benefits of this therapy, some studies show that there is a high level of non-compliance in patients that smoke. The study specifically mentions the hours of oxygen therapy that shows a relationship between both factors: patients with COPD that continue smoking carry out less hours of LTOT.
For all these reasons, it concluded that is essential to ensure an adequate compliance of LTOT and to quit smoking in order that the prescribed treatments are effective, as well as to achieve good control of the chronic obstructive pulmonary disease.