Source: DGNews  |  Posted 1 year ago

NEW YORK -- September 2, 2010 -- Palliative oxygen therapy offers no additional benefit over regular air when delivered by nasal cannula in relieving persistent dyspnoea in patients with terminal illness.

Thus less burdensome strategies should be considered for these patients, and if oxygen therapy is chosen to treat breathlessness then this should be within the context of a brief trial of treatment and careful assessment of benefit on an individual patient basis.

These are the conclusions of an article published in this week's European Respiratory Society meeting special issue of The Lancet, written by Amy P. Abernethy, MD, Duke University Medical Center, Durham, North Carolina, and colleagues.

Dyspnoea, a common symptom in very advanced stages of many diseases and disorders, is reported in 65%, 70% and 90% of patients nearing the end of life suffering from heart failure, lung cancer, and chronic obstructive pulmonary disease (COPD), respectively. Breathlessness is distressing for patients and their families, making normal activities like walking, talking, and socialising difficult.

Clinical guidelines recommend oxygen when blood oxygen levels fall so low that a patient becomes hypoxic, but there are large numbers of patients whose oxygen levels haven't fallen into the danger zone but who experience difficulty breathing and feel they need help. In situations like these, doctors tend to use palliative oxygen treatment out of compassion. To date, the decision has not been based on clear evidence on whether this was a meaningful intervention.

In this double-blind randomised controlled trial, adults from outpatient clinics at 9 sites in Australia, the US, and the UK were eligible for enrolment if they had life-limiting illness, untreatable breathlessness, and partial pressure of oxygen in arterial blood (PaO2) >7.3 kPa.

Patients were randomised to receive oxygen or room air via a concentrator through a nasal cannula at 2 L per min for 7 days. Participants were instructed to use the concentrator for at least 15 hours per day.

The primary outcome measure was breathlessness (0-10 numerical rating scale), measured twice a day (morning and evening).

A total of 239 participants were randomly assigned to treatment (oxygen120; room air, 119) of which 112 (93%) patients assigned to receive oxygen and 99 (83%) assigned to receive room air completed all 7 days of assessments. From baseline to day 6, mean morning breathlessness changed by -0.9 points in patients assigned to receive oxygen and by -0.7 points in patients assigned to receive room air, a difference that was not statistically significant.

Mean evening breathlessness changed by -0.3 points (-0.7 to 0.1) in the oxygen group and by -0.5 (-0.9 to -0.1) in the room air group (again not statistically significant). The frequency of side-effects did not differ between groups.

"Since oxygen delivered by a nasal cannula provides no additional symptomatic benefit for relief of refractory dyspnoea in patients with life-limiting illness compared with room air, less burdensome strategies should be considered after brief assessment of the effect of oxygen therapy on the individual patient," the authors wrote.

In an accompanying commentary, Irene J. Higginson, MD, Cicely Saunders Institute, King's College London, London, United Kingdom, said: "Abernethy and colleagues take us a step further in unpicking the evidence in the clinical management of breathlessness. Their results show that palliative oxygen does not provide incremental benefit over room air delivered by nasal cannula in improving morning/evening breathlessness for patients with advanced disease who are not hypoxic. They did not assess breathlessness during or after movement, so this point might need further exploration."

"The patients were attending outpatient clinics and thus were more functionally able. However, today's results suggest that, because oxygen provision can often provide a further barrier for patients as well as incurring health-care costs, its use in non-hypoxic patients should be avoided, unless there is a very good reason otherwise," she concluded.

SOURCE: The Lancet